Move FieldGroup and Vaadin 7 Grid to compatibility package

Change-Id: I9aaef478e0b67462641239802b924b8461cb9225

1 files changed, 7352 insertions, 0 deletions

diff --git a/compatibility-server/src/main/java/com/vaadin/ui/LegacyGrid.java b/compatibility-server/src/main/java/com/vaadin/ui/LegacyGrid.java
new file mode 100644
index 0000000000..9a98593b83
--- /dev/null
+++ b/compatibility-server/src/main/java/com/vaadin/ui/LegacyGrid.java
@@ -0,0 +1,7352 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.ui;
+
+import java.io.Serializable;
+import java.lang.reflect.Method;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.jsoup.nodes.Attributes;
+import org.jsoup.nodes.Element;
+import org.jsoup.select.Elements;
+
+import com.vaadin.data.Container;
+import com.vaadin.data.Container.Indexed;
+import com.vaadin.data.Container.ItemSetChangeEvent;
+import com.vaadin.data.Container.ItemSetChangeListener;
+import com.vaadin.data.Container.ItemSetChangeNotifier;
+import com.vaadin.data.Container.PropertySetChangeEvent;
+import com.vaadin.data.Container.PropertySetChangeListener;
+import com.vaadin.data.Container.PropertySetChangeNotifier;
+import com.vaadin.data.Container.Sortable;
+import com.vaadin.data.Item;
+import com.vaadin.data.Property;
+import com.vaadin.data.fieldgroup.DefaultFieldGroupFieldFactory;
+import com.vaadin.data.fieldgroup.FieldGroup;
+import com.vaadin.data.fieldgroup.FieldGroup.CommitException;
+import com.vaadin.data.fieldgroup.FieldGroupFieldFactory;
+import com.vaadin.data.sort.Sort;
+import com.vaadin.data.sort.SortOrder;
+import com.vaadin.data.util.IndexedContainer;
+import com.vaadin.event.ContextClickEvent;
+import com.vaadin.event.ItemClickEvent;
+import com.vaadin.event.ItemClickEvent.ItemClickListener;
+import com.vaadin.event.ItemClickEvent.ItemClickNotifier;
+import com.vaadin.event.SelectionEvent;
+import com.vaadin.event.SelectionEvent.SelectionListener;
+import com.vaadin.event.SelectionEvent.SelectionNotifier;
+import com.vaadin.event.SortEvent;
+import com.vaadin.event.SortEvent.SortListener;
+import com.vaadin.event.SortEvent.SortNotifier;
+import com.vaadin.server.AbstractClientConnector;
+import com.vaadin.server.AbstractExtension;
+import com.vaadin.server.EncodeResult;
+import com.vaadin.server.ErrorMessage;
+import com.vaadin.server.Extension;
+import com.vaadin.server.JsonCodec;
+import com.vaadin.server.KeyMapper;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.server.communication.data.DataGenerator;
+import com.vaadin.server.communication.data.RpcDataProviderExtension;
+import com.vaadin.shared.MouseEventDetails;
+import com.vaadin.shared.data.sort.SortDirection;
+import com.vaadin.shared.ui.grid.EditorClientRpc;
+import com.vaadin.shared.ui.grid.EditorServerRpc;
+import com.vaadin.shared.ui.grid.GridClientRpc;
+import com.vaadin.shared.ui.grid.GridColumnState;
+import com.vaadin.shared.ui.grid.GridConstants;
+import com.vaadin.shared.ui.grid.GridConstants.Section;
+import com.vaadin.shared.ui.grid.GridServerRpc;
+import com.vaadin.shared.ui.grid.GridState;
+import com.vaadin.shared.ui.grid.GridStaticCellType;
+import com.vaadin.shared.ui.grid.GridStaticSectionState;
+import com.vaadin.shared.ui.grid.GridStaticSectionState.CellState;
+import com.vaadin.shared.ui.grid.GridStaticSectionState.RowState;
+import com.vaadin.shared.ui.grid.HeightMode;
+import com.vaadin.shared.ui.grid.ScrollDestination;
+import com.vaadin.shared.ui.grid.selection.MultiSelectionModelServerRpc;
+import com.vaadin.shared.ui.grid.selection.MultiSelectionModelState;
+import com.vaadin.shared.ui.grid.selection.SingleSelectionModelServerRpc;
+import com.vaadin.shared.ui.grid.selection.SingleSelectionModelState;
+import com.vaadin.shared.util.SharedUtil;
+import com.vaadin.ui.declarative.DesignAttributeHandler;
+import com.vaadin.ui.declarative.DesignContext;
+import com.vaadin.ui.declarative.DesignException;
+import com.vaadin.ui.declarative.DesignFormatter;
+import com.vaadin.ui.renderers.HtmlRenderer;
+import com.vaadin.ui.renderers.Renderer;
+import com.vaadin.ui.renderers.TextRenderer;
+import com.vaadin.util.ReflectTools;
+import com.vaadin.v7.data.Validator.InvalidValueException;
+import com.vaadin.v7.data.util.converter.LegacyConverter;
+import com.vaadin.v7.data.util.converter.LegacyConverterUtil;
+import com.vaadin.v7.ui.LegacyCheckBox;
+import com.vaadin.v7.ui.LegacyField;
+
+import elemental.json.Json;
+import elemental.json.JsonObject;
+import elemental.json.JsonValue;
+
+/**
+ * A grid component for displaying tabular data.
+ * <p>
+ * Grid is always bound to a {@link Container.Indexed}, but is not a
+ * {@code Container} of any kind in of itself. The contents of the given
+ * Container is displayed with the help of {@link Renderer Renderers}.
+ *
+ * <h3 id="grid-headers-and-footers">Headers and Footers</h3>
+ * <p>
+ *
+ *
+ * <h3 id="grid-converters-and-renderers">Converters and Renderers</h3>
+ * <p>
+ * Each column has its own {@link Renderer} that displays data into something
+ * that can be displayed in the browser. That data is first converted with a
+ * {@link com.vaadin.v7.data.util.converter.LegacyConverter Converter} into
+ * something that the Renderer can process. This can also be an implicit step -
+ * if a column has a simple data type, like a String, no explicit assignment is
+ * needed.
+ * <p>
+ * Usually a renderer takes some kind of object, and converts it into a
+ * HTML-formatted string.
+ * <p>
+ * <code><pre>
+ * Grid grid = new Grid(myContainer);
+ * Column column = grid.getColumn(STRING_DATE_PROPERTY);
+ * column.setConverter(new StringToDateConverter());
+ * column.setRenderer(new MyColorfulDateRenderer());
+ * </pre></code>
+ *
+ * <h3 id="grid-lazyloading">Lazy Loading</h3>
+ * <p>
+ * The data is accessed as it is needed by Grid and not any sooner. In other
+ * words, if the given Container is huge, but only the first few rows are
+ * displayed to the user, only those (and a few more, for caching purposes) are
+ * accessed.
+ *
+ * <h3 id="grid-selection-modes-and-models">Selection Modes and Models</h3>
+ * <p>
+ * Grid supports three selection <em>{@link SelectionMode modes}</em> (single,
+ * multi, none), and comes bundled with one <em>{@link SelectionModel
+ * model}</em> for each of the modes. The distinction between a selection mode
+ * and selection model is as follows: a <em>mode</em> essentially says whether
+ * you can have one, many or no rows selected. The model, however, has the
+ * behavioral details of each. A single selection model may require that the
+ * user deselects one row before selecting another one. A variant of a
+ * multiselect might have a configurable maximum of rows that may be selected.
+ * And so on.
+ * <p>
+ * <code><pre>
+ * Grid grid = new Grid(myContainer);
+ *
+ * // uses the bundled SingleSelectionModel class
+ * grid.setSelectionMode(SelectionMode.SINGLE);
+ *
+ * // changes the behavior to a custom selection model
+ * grid.setSelectionModel(new MyTwoSelectionModel());
+ * </pre></code>
+ *
+ * @since 7.4
+ * @author Vaadin Ltd
+ */
+public class LegacyGrid extends AbstractFocusable implements SelectionNotifier,
+        SortNotifier, SelectiveRenderer, ItemClickNotifier {
+
+    /**
+     * An event listener for column visibility change events in the Grid.
+     *
+     * @since 7.5.0
+     */
+    public interface ColumnVisibilityChangeListener extends Serializable {
+        /**
+         * Called when a column has become hidden or unhidden.
+         *
+         * @param event
+         */
+        void columnVisibilityChanged(ColumnVisibilityChangeEvent event);
+    }
+
+    /**
+     * An event that is fired when a column's visibility changes.
+     *
+     * @since 7.5.0
+     */
+    public static class ColumnVisibilityChangeEvent extends Component.Event {
+
+        private final Column column;
+        private final boolean userOriginated;
+        private final boolean hidden;
+
+        /**
+         * Constructor for a column visibility change event.
+         *
+         * @param source
+         *            the grid from which this event originates
+         * @param column
+         *            the column that changed its visibility
+         * @param hidden
+         *            <code>true</code> if the column was hidden,
+         *            <code>false</code> if it became visible
+         * @param isUserOriginated
+         *            <code>true</code> iff the event was triggered by an UI
+         *            interaction
+         */
+        public ColumnVisibilityChangeEvent(LegacyGrid source, Column column,
+                boolean hidden, boolean isUserOriginated) {
+            super(source);
+            this.column = column;
+            this.hidden = hidden;
+            userOriginated = isUserOriginated;
+        }
+
+        /**
+         * Gets the column that became hidden or visible.
+         *
+         * @return the column that became hidden or visible.
+         * @see Column#isHidden()
+         */
+        public Column getColumn() {
+            return column;
+        }
+
+        /**
+         * Was the column set hidden or visible.
+         *
+         * @return <code>true</code> if the column was hidden <code>false</code>
+         *         if it was set visible
+         */
+        public boolean isHidden() {
+            return hidden;
+        }
+
+        /**
+         * Returns <code>true</code> if the column reorder was done by the user,
+         * <code>false</code> if not and it was triggered by server side code.
+         *
+         * @return <code>true</code> if event is a result of user interaction
+         */
+        public boolean isUserOriginated() {
+            return userOriginated;
+        }
+    }
+
+    /**
+     * A callback interface for generating details for a particular row in Grid.
+     *
+     * @since 7.5.0
+     * @author Vaadin Ltd
+     * @see DetailsGenerator#NULL
+     */
+    public interface DetailsGenerator extends Serializable {
+
+        /** A details generator that provides no details */
+        public DetailsGenerator NULL = new DetailsGenerator() {
+            @Override
+            public Component getDetails(RowReference rowReference) {
+                return null;
+            }
+        };
+
+        /**
+         * This method is called for whenever a details row needs to be shown on
+         * the client. Grid removes all of its references to details components
+         * when they are no longer displayed on the client-side and will
+         * re-request once needed again.
+         * <p>
+         * <em>Note:</em> If a component gets generated, it may not be manually
+         * attached anywhere. The same details component can not be displayed
+         * for multiple different rows.
+         *
+         * @param rowReference
+         *            the reference for the row for which to generate details
+         * @return the details for the given row, or <code>null</code> to leave
+         *         the details empty.
+         */
+        Component getDetails(RowReference rowReference);
+    }
+
+    /**
+     * A class that manages details components by calling
+     * {@link DetailsGenerator} as needed. Details components are attached by
+     * this class when the {@link RpcDataProviderExtension} is sending data to
+     * the client. Details components are detached and forgotten when client
+     * informs that it has dropped the corresponding item.
+     *
+     * @since 7.6.1
+     */
+    public final static class DetailComponentManager
+            extends AbstractGridExtension implements DataGenerator {
+
+        /**
+         * The user-defined details generator.
+         *
+         * @see #setDetailsGenerator(DetailsGenerator)
+         */
+        private DetailsGenerator detailsGenerator;
+
+        /**
+         * This map represents all details that are currently visible on the
+         * client. Details components get destroyed once they scroll out of
+         * view.
+         */
+        private final Map<Object, Component> itemIdToDetailsComponent = new HashMap<>();
+
+        /**
+         * Set of item ids that got <code>null</code> from DetailsGenerator when
+         * {@link DetailsGenerator#getDetails(RowReference)} was called.
+         */
+        private final Set<Object> emptyDetails = new HashSet<>();
+
+        /**
+         * Set of item IDs for all open details rows. Contains even the ones
+         * that are not currently visible on the client.
+         */
+        private final Set<Object> openDetails = new HashSet<>();
+
+        public DetailComponentManager(LegacyGrid grid) {
+            this(grid, DetailsGenerator.NULL);
+        }
+
+        public DetailComponentManager(LegacyGrid grid,
+                DetailsGenerator detailsGenerator) {
+            super(grid);
+            setDetailsGenerator(detailsGenerator);
+        }
+
+        /**
+         * Creates a details component with the help of the user-defined
+         * {@link DetailsGenerator}.
+         * <p>
+         * This method attaches created components to the parent {@link LegacyGrid}.
+         *
+         * @param itemId
+         *            the item id for which to create the details component.
+         * @throws IllegalStateException
+         *             if the current details generator provides a component
+         *             that was manually attached.
+         */
+        private void createDetails(Object itemId) throws IllegalStateException {
+            assert itemId != null : "itemId was null";
+
+            if (itemIdToDetailsComponent.containsKey(itemId)
+                    || emptyDetails.contains(itemId)) {
+                // Don't overwrite existing components
+                return;
+            }
+
+            RowReference rowReference = new RowReference(getParentGrid());
+            rowReference.set(itemId);
+
+            DetailsGenerator detailsGenerator = getParentGrid()
+                    .getDetailsGenerator();
+            Component details = detailsGenerator.getDetails(rowReference);
+            if (details != null) {
+                if (details.getParent() != null) {
+                    String name = detailsGenerator.getClass().getName();
+                    throw new IllegalStateException(
+                            name + " generated a details component that already "
+                                    + "was attached. (itemId: " + itemId
+                                    + ", component: " + details + ")");
+                }
+
+                itemIdToDetailsComponent.put(itemId, details);
+
+                addComponentToGrid(details);
+
+                assert !emptyDetails.contains(itemId) : "Bookeeping thinks "
+                        + "itemId is empty even though we just created a "
+                        + "component for it (" + itemId + ")";
+            } else {
+                emptyDetails.add(itemId);
+            }
+
+        }
+
+        /**
+         * Destroys a details component correctly.
+         * <p>
+         * This method will detach the component from parent {@link LegacyGrid}.
+         *
+         * @param itemId
+         *            the item id for which to destroy the details component
+         */
+        private void destroyDetails(Object itemId) {
+            emptyDetails.remove(itemId);
+
+            Component removedComponent = itemIdToDetailsComponent
+                    .remove(itemId);
+            if (removedComponent == null) {
+                return;
+            }
+
+            removeComponentFromGrid(removedComponent);
+        }
+
+        /**
+         * Recreates all visible details components.
+         */
+        public void refreshDetails() {
+            Set<Object> visibleItemIds = new HashSet<>(
+                    itemIdToDetailsComponent.keySet());
+            for (Object itemId : visibleItemIds) {
+                destroyDetails(itemId);
+                createDetails(itemId);
+                refreshRow(itemId);
+            }
+        }
+
+        /**
+         * Sets details visiblity status of given item id.
+         *
+         * @param itemId
+         *            item id to set
+         * @param visible
+         *            <code>true</code> if visible; <code>false</code> if not
+         */
+        public void setDetailsVisible(Object itemId, boolean visible) {
+            if ((visible && openDetails.contains(itemId))
+                    || (!visible && !openDetails.contains(itemId))) {
+                return;
+            }
+
+            if (visible) {
+                openDetails.add(itemId);
+                refreshRow(itemId);
+            } else {
+                openDetails.remove(itemId);
+                destroyDetails(itemId);
+                refreshRow(itemId);
+            }
+        }
+
+        @Override
+        public void generateData(Object itemId, Item item, JsonObject rowData) {
+            // DetailComponentManager should not send anything if details
+            // generator is the default null version.
+            if (openDetails.contains(itemId)
+                    && !detailsGenerator.equals(DetailsGenerator.NULL)) {
+                // Double check to be sure details component exists.
+                createDetails(itemId);
+
+                Component detailsComponent = itemIdToDetailsComponent
+                        .get(itemId);
+                rowData.put(GridState.JSONKEY_DETAILS_VISIBLE,
+                        (detailsComponent != null
+                                ? detailsComponent.getConnectorId() : ""));
+            }
+        }
+
+        @Override
+        public void destroyData(Object itemId) {
+            if (openDetails.contains(itemId)) {
+                destroyDetails(itemId);
+            }
+        }
+
+        /**
+         * Sets a new details generator for row details.
+         * <p>
+         * The currently opened row details will be re-rendered.
+         *
+         * @param detailsGenerator
+         *            the details generator to set
+         * @throws IllegalArgumentException
+         *             if detailsGenerator is <code>null</code>;
+         */
+        public void setDetailsGenerator(DetailsGenerator detailsGenerator)
+                throws IllegalArgumentException {
+            if (detailsGenerator == null) {
+                throw new IllegalArgumentException(
+                        "Details generator may not be null");
+            } else if (detailsGenerator == this.detailsGenerator) {
+                return;
+            }
+
+            this.detailsGenerator = detailsGenerator;
+
+            refreshDetails();
+        }
+
+        /**
+         * Gets the current details generator for row details.
+         *
+         * @return the detailsGenerator the current details generator
+         */
+        public DetailsGenerator getDetailsGenerator() {
+            return detailsGenerator;
+        }
+
+        /**
+         * Checks whether details are visible for the given item.
+         *
+         * @param itemId
+         *            the id of the item for which to check details visibility
+         * @return <code>true</code> iff the details are visible
+         */
+        public boolean isDetailsVisible(Object itemId) {
+            return openDetails.contains(itemId);
+        }
+    }
+
+    /**
+     * Custom field group that allows finding property types before an item has
+     * been bound.
+     */
+    private final class CustomFieldGroup extends FieldGroup {
+
+        public CustomFieldGroup() {
+            setFieldFactory(EditorFieldFactory.get());
+        }
+
+        @Override
+        protected Class<?> getPropertyType(Object propertyId)
+                throws BindException {
+            if (getItemDataSource() == null) {
+                return datasource.getType(propertyId);
+            } else {
+                return super.getPropertyType(propertyId);
+            }
+        }
+
+        @Override
+        protected <T extends LegacyField> T build(String caption,
+                Class<?> dataType, Class<T> fieldType) throws BindException {
+            T field = super.build(caption, dataType, fieldType);
+            if (field instanceof LegacyCheckBox) {
+                field.setCaption(null);
+            }
+            return field;
+        }
+    }
+
+    /**
+     * Field factory used by default in the editor.
+     *
+     * Aims to fields of suitable type and with suitable size for use in the
+     * editor row.
+     */
+    public static class EditorFieldFactory
+            extends DefaultFieldGroupFieldFactory {
+        private static final EditorFieldFactory INSTANCE = new EditorFieldFactory();
+
+        protected EditorFieldFactory() {
+        }
+
+        /**
+         * Returns the singleton instance
+         *
+         * @return the singleton instance
+         */
+        public static EditorFieldFactory get() {
+            return INSTANCE;
+        }
+
+        @Override
+        public <T extends LegacyField> T createField(Class<?> type,
+                Class<T> fieldType) {
+            T f = super.createField(type, fieldType);
+            if (f != null) {
+                f.setWidth("100%");
+            }
+            return f;
+        }
+
+        @Override
+        protected AbstractSelect createCompatibleSelect(
+                Class<? extends AbstractSelect> fieldType) {
+            if (anySelect(fieldType)) {
+                return super.createCompatibleSelect(ComboBox.class);
+            }
+            return super.createCompatibleSelect(fieldType);
+        }
+
+        @Override
+        protected void populateWithEnumData(AbstractSelect select,
+                Class<? extends Enum> enumClass) {
+            // Use enums directly and the EnumToStringConverter to be consistent
+            // with what is shown in the Grid
+            @SuppressWarnings("unchecked")
+            EnumSet<?> enumSet = EnumSet.allOf(enumClass);
+            for (Object r : enumSet) {
+                select.addItem(r);
+            }
+        }
+    }
+
+    /**
+     * Error handler for the editor
+     */
+    public interface EditorErrorHandler extends Serializable {
+
+        /**
+         * Called when an exception occurs while the editor row is being saved
+         *
+         * @param event
+         *            An event providing more information about the error
+         */
+        void commitError(CommitErrorEvent event);
+    }
+
+    /**
+     * ContextClickEvent for the Grid Component.
+     *
+     * @since 7.6
+     */
+    public static class GridContextClickEvent extends ContextClickEvent {
+
+        private final Object itemId;
+        private final int rowIndex;
+        private final Object propertyId;
+        private final Section section;
+
+        public GridContextClickEvent(LegacyGrid source,
+                MouseEventDetails mouseEventDetails, Section section,
+                int rowIndex, Object itemId, Object propertyId) {
+            super(source, mouseEventDetails);
+            this.itemId = itemId;
+            this.propertyId = propertyId;
+            this.section = section;
+            this.rowIndex = rowIndex;
+        }
+
+        /**
+         * Returns the item id of context clicked row.
+         *
+         * @return item id of clicked row; <code>null</code> if header or footer
+         */
+        public Object getItemId() {
+            return itemId;
+        }
+
+        /**
+         * Returns property id of clicked column.
+         *
+         * @return property id
+         */
+        public Object getPropertyId() {
+            return propertyId;
+        }
+
+        /**
+         * Return the clicked section of Grid.
+         *
+         * @return section of grid
+         */
+        public Section getSection() {
+            return section;
+        }
+
+        /**
+         * Returns the clicked row index relative to Grid section. In the body
+         * of the Grid the index is the item index in the Container. Header and
+         * Footer rows for index can be fetched with
+         * {@link LegacyGrid#getHeaderRow(int)} and {@link LegacyGrid#getFooterRow(int)}.
+         *
+         * @return row index in section
+         */
+        public int getRowIndex() {
+            return rowIndex;
+        }
+
+        @Override
+        public LegacyGrid getComponent() {
+            return (LegacyGrid) super.getComponent();
+        }
+    }
+
+    /**
+     * An event which is fired when saving the editor fails
+     */
+    public static class CommitErrorEvent extends Component.Event {
+
+        private CommitException cause;
+
+        private Set<Column> errorColumns = new HashSet<>();
+
+        private String userErrorMessage;
+
+        public CommitErrorEvent(LegacyGrid grid, CommitException cause) {
+            super(grid);
+            this.cause = cause;
+            userErrorMessage = cause.getLocalizedMessage();
+        }
+
+        /**
+         * Retrieves the cause of the failure
+         *
+         * @return the cause of the failure
+         */
+        public CommitException getCause() {
+            return cause;
+        }
+
+        @Override
+        public LegacyGrid getComponent() {
+            return (LegacyGrid) super.getComponent();
+        }
+
+        /**
+         * Checks if validation exceptions caused this error
+         *
+         * @return true if the problem was caused by a validation error
+         */
+        public boolean isValidationFailure() {
+            return cause.getCause() instanceof InvalidValueException;
+        }
+
+        /**
+         * Marks that an error indicator should be shown for the editor of a
+         * column.
+         *
+         * @param column
+         *            the column to show an error for
+         */
+        public void addErrorColumn(Column column) {
+            errorColumns.add(column);
+        }
+
+        /**
+         * Gets all the columns that have been marked as erroneous.
+         *
+         * @return an umodifiable collection of erroneous columns
+         */
+        public Collection<Column> getErrorColumns() {
+            return Collections.unmodifiableCollection(errorColumns);
+        }
+
+        /**
+         * Gets the error message to show to the user.
+         *
+         * @return error message to show
+         */
+        public String getUserErrorMessage() {
+            return userErrorMessage;
+        }
+
+        /**
+         * Sets the error message to show to the user.
+         *
+         * @param userErrorMessage
+         *            the user error message to set
+         */
+        public void setUserErrorMessage(String userErrorMessage) {
+            this.userErrorMessage = userErrorMessage;
+        }
+
+    }
+
+    /**
+     * An event listener for column reorder events in the Grid.
+     *
+     * @since 7.5.0
+     */
+    public interface ColumnReorderListener extends Serializable {
+
+        /**
+         * Called when the columns of the grid have been reordered.
+         *
+         * @param event
+         *            An event providing more information
+         */
+        void columnReorder(ColumnReorderEvent event);
+    }
+
+    /**
+     * An event that is fired when the columns are reordered.
+     *
+     * @since 7.5.0
+     */
+    public static class ColumnReorderEvent extends Component.Event {
+
+        private final boolean userOriginated;
+
+        /**
+         *
+         * @param source
+         *            the grid where the event originated from
+         * @param userOriginated
+         *            <code>true</code> if event is a result of user
+         *            interaction, <code>false</code> if from API call
+         */
+        public ColumnReorderEvent(LegacyGrid source, boolean userOriginated) {
+            super(source);
+            this.userOriginated = userOriginated;
+        }
+
+        /**
+         * Returns <code>true</code> if the column reorder was done by the user,
+         * <code>false</code> if not and it was triggered by server side code.
+         *
+         * @return <code>true</code> if event is a result of user interaction
+         */
+        public boolean isUserOriginated() {
+            return userOriginated;
+        }
+
+    }
+
+    /**
+     * An event listener for column resize events in the Grid.
+     *
+     * @since 7.6
+     */
+    public interface ColumnResizeListener extends Serializable {
+
+        /**
+         * Called when the columns of the grid have been resized.
+         *
+         * @param event
+         *            An event providing more information
+         */
+        void columnResize(ColumnResizeEvent event);
+    }
+
+    /**
+     * An event that is fired when a column is resized, either programmatically
+     * or by the user.
+     *
+     * @since 7.6
+     */
+    public static class ColumnResizeEvent extends Component.Event {
+
+        private final Column column;
+        private final boolean userOriginated;
+
+        /**
+         *
+         * @param source
+         *            the grid where the event originated from
+         * @param userOriginated
+         *            <code>true</code> if event is a result of user
+         *            interaction, <code>false</code> if from API call
+         */
+        public ColumnResizeEvent(LegacyGrid source, Column column,
+                boolean userOriginated) {
+            super(source);
+            this.column = column;
+            this.userOriginated = userOriginated;
+        }
+
+        /**
+         * Returns the column that was resized.
+         *
+         * @return the resized column.
+         */
+        public Column getColumn() {
+            return column;
+        }
+
+        /**
+         * Returns <code>true</code> if the column resize was done by the user,
+         * <code>false</code> if not and it was triggered by server side code.
+         *
+         * @return <code>true</code> if event is a result of user interaction
+         */
+        public boolean isUserOriginated() {
+            return userOriginated;
+        }
+
+    }
+
+    /**
+     * Interface for an editor event listener
+     */
+    public interface EditorListener extends Serializable {
+
+        public static final Method EDITOR_OPEN_METHOD = ReflectTools.findMethod(
+                EditorListener.class, "editorOpened", EditorOpenEvent.class);
+        public static final Method EDITOR_MOVE_METHOD = ReflectTools.findMethod(
+                EditorListener.class, "editorMoved", EditorMoveEvent.class);
+        public static final Method EDITOR_CLOSE_METHOD = ReflectTools
+                .findMethod(EditorListener.class, "editorClosed",
+                        EditorCloseEvent.class);
+
+        /**
+         * Called when an editor is opened
+         *
+         * @param e
+         *            an editor open event object
+         */
+        public void editorOpened(EditorOpenEvent e);
+
+        /**
+         * Called when an editor is reopened without closing it first
+         *
+         * @param e
+         *            an editor move event object
+         */
+        public void editorMoved(EditorMoveEvent e);
+
+        /**
+         * Called when an editor is closed
+         *
+         * @param e
+         *            an editor close event object
+         */
+        public void editorClosed(EditorCloseEvent e);
+
+    }
+
+    /**
+     * Base class for editor related events
+     */
+    public static abstract class EditorEvent extends Component.Event {
+
+        private Object itemID;
+
+        protected EditorEvent(LegacyGrid source, Object itemID) {
+            super(source);
+            this.itemID = itemID;
+        }
+
+        /**
+         * Get the item (row) for which this editor was opened
+         */
+        public Object getItem() {
+            return itemID;
+        }
+
+    }
+
+    /**
+     * This event gets fired when an editor is opened
+     */
+    public static class EditorOpenEvent extends EditorEvent {
+
+        public EditorOpenEvent(LegacyGrid source, Object itemID) {
+            super(source, itemID);
+        }
+    }
+
+    /**
+     * This event gets fired when an editor is opened while another row is being
+     * edited (i.e. editor focus moves elsewhere)
+     */
+    public static class EditorMoveEvent extends EditorEvent {
+
+        public EditorMoveEvent(LegacyGrid source, Object itemID) {
+            super(source, itemID);
+        }
+    }
+
+    /**
+     * This event gets fired when an editor is dismissed or closed by other
+     * means.
+     */
+    public static class EditorCloseEvent extends EditorEvent {
+
+        public EditorCloseEvent(LegacyGrid source, Object itemID) {
+            super(source, itemID);
+        }
+    }
+
+    /**
+     * Default error handler for the editor
+     *
+     */
+    public class DefaultEditorErrorHandler implements EditorErrorHandler {
+
+        @Override
+        public void commitError(CommitErrorEvent event) {
+            Map<LegacyField<?>, InvalidValueException> invalidFields = event
+                    .getCause().getInvalidFields();
+
+            if (!invalidFields.isEmpty()) {
+                Object firstErrorPropertyId = null;
+                LegacyField<?> firstErrorField = null;
+
+                FieldGroup fieldGroup = event.getCause().getFieldGroup();
+                for (Column column : getColumns()) {
+                    Object propertyId = column.getPropertyId();
+                    LegacyField<?> field = fieldGroup.getField(propertyId);
+                    if (invalidFields.keySet().contains(field)) {
+                        event.addErrorColumn(column);
+
+                        if (firstErrorPropertyId == null) {
+                            firstErrorPropertyId = propertyId;
+                            firstErrorField = field;
+                        }
+                    }
+                }
+
+                /*
+                 * Validation error, show first failure as
+                 * "<Column header>: <message>"
+                 */
+                String caption = getColumn(firstErrorPropertyId)
+                        .getHeaderCaption();
+                String message = invalidFields.get(firstErrorField)
+                        .getLocalizedMessage();
+
+                event.setUserErrorMessage(caption + ": " + message);
+            } else {
+                com.vaadin.server.ErrorEvent.findErrorHandler(LegacyGrid.this).error(
+                        new ConnectorErrorEvent(LegacyGrid.this, event.getCause()));
+            }
+        }
+
+        private Object getFirstPropertyId(FieldGroup fieldGroup,
+                Set<LegacyField<?>> keySet) {
+            for (Column c : getColumns()) {
+                Object propertyId = c.getPropertyId();
+                LegacyField<?> f = fieldGroup.getField(propertyId);
+                if (keySet.contains(f)) {
+                    return propertyId;
+                }
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Selection modes representing built-in {@link SelectionModel
+     * SelectionModels} that come bundled with {@link LegacyGrid}.
+     * <p>
+     * Passing one of these enums into
+     * {@link LegacyGrid#setSelectionMode(SelectionMode)} is equivalent to calling
+     * {@link LegacyGrid#setSelectionModel(SelectionModel)} with one of the built-in
+     * implementations of {@link SelectionModel}.
+     *
+     * @see LegacyGrid#setSelectionMode(SelectionMode)
+     * @see LegacyGrid#setSelectionModel(SelectionModel)
+     */
+    public enum SelectionMode {
+        /** A SelectionMode that maps to {@link SingleSelectionModel} */
+        SINGLE {
+            @Override
+            protected SelectionModel createModel() {
+                return new SingleSelectionModel();
+            }
+
+        },
+
+        /** A SelectionMode that maps to {@link MultiSelectionModel} */
+        MULTI {
+            @Override
+            protected SelectionModel createModel() {
+                return new MultiSelectionModel();
+            }
+        },
+
+        /** A SelectionMode that maps to {@link NoSelectionModel} */
+        NONE {
+            @Override
+            protected SelectionModel createModel() {
+                return new NoSelectionModel();
+            }
+        };
+
+        protected abstract SelectionModel createModel();
+    }
+
+    /**
+     * The server-side interface that controls Grid's selection state.
+     * SelectionModel should extend {@link AbstractGridExtension}.
+     */
+    public interface SelectionModel extends Serializable, Extension {
+        /**
+         * Checks whether an item is selected or not.
+         *
+         * @param itemId
+         *            the item id to check for
+         * @return <code>true</code> iff the item is selected
+         */
+        boolean isSelected(Object itemId);
+
+        /**
+         * Returns a collection of all the currently selected itemIds.
+         *
+         * @return a collection of all the currently selected itemIds
+         */
+        Collection<Object> getSelectedRows();
+
+        /**
+         * Injects the current {@link LegacyGrid} instance into the SelectionModel.
+         * This method should usually call the extend method of
+         * {@link AbstractExtension}.
+         * <p>
+         * <em>Note:</em> This method should not be called manually.
+         *
+         * @param grid
+         *            the Grid in which the SelectionModel currently is, or
+         *            <code>null</code> when a selection model is being detached
+         *            from a Grid.
+         */
+        void setGrid(LegacyGrid grid);
+
+        /**
+         * Resets the SelectiomModel to an initial state.
+         * <p>
+         * Most often this means that the selection state is cleared, but
+         * implementations are free to interpret the "initial state" as they
+         * wish. Some, for example, may want to keep the first selected item as
+         * selected.
+         */
+        void reset();
+
+        /**
+         * A SelectionModel that supports multiple selections to be made.
+         * <p>
+         * This interface has a contract of having the same behavior, no matter
+         * how the selection model is interacted with. In other words, if
+         * something is forbidden to do in e.g. the user interface, it must also
+         * be forbidden to do in the server-side and client-side APIs.
+         */
+        public interface Multi extends SelectionModel {
+
+            /**
+             * Marks items as selected.
+             * <p>
+             * This method does not clear any previous selection state, only
+             * adds to it.
+             *
+             * @param itemIds
+             *            the itemId(s) to mark as selected
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if all the given itemIds already were
+             *         selected
+             * @throws IllegalArgumentException
+             *             if the <code>itemIds</code> varargs array is
+             *             <code>null</code> or given itemIds don't exist in the
+             *             container of Grid
+             * @see #deselect(Object...)
+             */
+            boolean select(Object... itemIds) throws IllegalArgumentException;
+
+            /**
+             * Marks items as selected.
+             * <p>
+             * This method does not clear any previous selection state, only
+             * adds to it.
+             *
+             * @param itemIds
+             *            the itemIds to mark as selected
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if all the given itemIds already were
+             *         selected
+             * @throws IllegalArgumentException
+             *             if <code>itemIds</code> is <code>null</code> or given
+             *             itemIds don't exist in the container of Grid
+             * @see #deselect(Collection)
+             */
+            boolean select(Collection<?> itemIds)
+                    throws IllegalArgumentException;
+
+            /**
+             * Marks items as deselected.
+             *
+             * @param itemIds
+             *            the itemId(s) to remove from being selected
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if none the given itemIds were
+             *         selected previously
+             * @throws IllegalArgumentException
+             *             if the <code>itemIds</code> varargs array is
+             *             <code>null</code>
+             * @see #select(Object...)
+             */
+            boolean deselect(Object... itemIds) throws IllegalArgumentException;
+
+            /**
+             * Marks items as deselected.
+             *
+             * @param itemIds
+             *            the itemId(s) to remove from being selected
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if none the given itemIds were
+             *         selected previously
+             * @throws IllegalArgumentException
+             *             if <code>itemIds</code> is <code>null</code>
+             * @see #select(Collection)
+             */
+            boolean deselect(Collection<?> itemIds)
+                    throws IllegalArgumentException;
+
+            /**
+             * Marks all the items in the current Container as selected
+             *
+             * @return <code>true</code> iff some items were previously not
+             *         selected
+             * @see #deselectAll()
+             */
+            boolean selectAll();
+
+            /**
+             * Marks all the items in the current Container as deselected
+             *
+             * @return <code>true</code> iff some items were previously selected
+             * @see #selectAll()
+             */
+            boolean deselectAll();
+
+            /**
+             * Marks items as selected while deselecting all items not in the
+             * given Collection.
+             *
+             * @param itemIds
+             *            the itemIds to mark as selected
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if all the given itemIds already were
+             *         selected
+             * @throws IllegalArgumentException
+             *             if <code>itemIds</code> is <code>null</code> or given
+             *             itemIds don't exist in the container of Grid
+             */
+            boolean setSelected(Collection<?> itemIds)
+                    throws IllegalArgumentException;
+
+            /**
+             * Marks items as selected while deselecting all items not in the
+             * varargs array.
+             *
+             * @param itemIds
+             *            the itemIds to mark as selected
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if all the given itemIds already were
+             *         selected
+             * @throws IllegalArgumentException
+             *             if the <code>itemIds</code> varargs array is
+             *             <code>null</code> or given itemIds don't exist in the
+             *             container of Grid
+             */
+            boolean setSelected(Object... itemIds)
+                    throws IllegalArgumentException;
+        }
+
+        /**
+         * A SelectionModel that supports for only single rows to be selected at
+         * a time.
+         * <p>
+         * This interface has a contract of having the same behavior, no matter
+         * how the selection model is interacted with. In other words, if
+         * something is forbidden to do in e.g. the user interface, it must also
+         * be forbidden to do in the server-side and client-side APIs.
+         */
+        public interface Single extends SelectionModel {
+
+            /**
+             * Marks an item as selected.
+             *
+             * @param itemId
+             *            the itemId to mark as selected; <code>null</code> for
+             *            deselect
+             * @return <code>true</code> if the selection state changed.
+             *         <code>false</code> if the itemId already was selected
+             * @throws IllegalStateException
+             *             if the selection was illegal. One such reason might
+             *             be that the given id was null, indicating a deselect,
+             *             but implementation doesn't allow deselecting.
+             *             re-selecting something
+             * @throws IllegalArgumentException
+             *             if given itemId does not exist in the container of
+             *             Grid
+             */
+            boolean select(Object itemId)
+                    throws IllegalStateException, IllegalArgumentException;
+
+            /**
+             * Gets the item id of the currently selected item.
+             *
+             * @return the item id of the currently selected item, or
+             *         <code>null</code> if nothing is selected
+             */
+            Object getSelectedRow();
+
+            /**
+             * Sets whether it's allowed to deselect the selected row through
+             * the UI. Deselection is allowed by default.
+             *
+             * @param deselectAllowed
+             *            <code>true</code> if the selected row can be
+             *            deselected without selecting another row instead;
+             *            otherwise <code>false</code>.
+             */
+            public void setDeselectAllowed(boolean deselectAllowed);
+
+            /**
+             * Sets whether it's allowed to deselect the selected row through
+             * the UI.
+             *
+             * @return <code>true</code> if deselection is allowed; otherwise
+             *         <code>false</code>
+             */
+            public boolean isDeselectAllowed();
+        }
+
+        /**
+         * A SelectionModel that does not allow for rows to be selected.
+         * <p>
+         * This interface has a contract of having the same behavior, no matter
+         * how the selection model is interacted with. In other words, if the
+         * developer is unable to select something programmatically, it is not
+         * allowed for the end-user to select anything, either.
+         */
+        public interface None extends SelectionModel {
+
+            /**
+             * {@inheritDoc}
+             *
+             * @return always <code>false</code>.
+             */
+            @Override
+            public boolean isSelected(Object itemId);
+
+            /**
+             * {@inheritDoc}
+             *
+             * @return always an empty collection.
+             */
+            @Override
+            public Collection<Object> getSelectedRows();
+        }
+    }
+
+    /**
+     * A base class for SelectionModels that contains some of the logic that is
+     * reusable.
+     */
+    public static abstract class AbstractSelectionModel extends
+            AbstractGridExtension implements SelectionModel, DataGenerator {
+        protected final LinkedHashSet<Object> selection = new LinkedHashSet<>();
+
+        @Override
+        public boolean isSelected(final Object itemId) {
+            return selection.contains(itemId);
+        }
+
+        @Override
+        public Collection<Object> getSelectedRows() {
+            return new ArrayList<>(selection);
+        }
+
+        @Override
+        public void setGrid(final LegacyGrid grid) {
+            if (grid != null) {
+                extend(grid);
+            }
+        }
+
+        /**
+         * Sanity check for existence of item id.
+         *
+         * @param itemId
+         *            item id to be selected / deselected
+         *
+         * @throws IllegalArgumentException
+         *             if item Id doesn't exist in the container of Grid
+         */
+        protected void checkItemIdExists(Object itemId)
+                throws IllegalArgumentException {
+            if (!getParentGrid().getContainerDataSource().containsId(itemId)) {
+                throw new IllegalArgumentException("Given item id (" + itemId
+                        + ") does not exist in the container");
+            }
+        }
+
+        /**
+         * Sanity check for existence of item ids in given collection.
+         *
+         * @param itemIds
+         *            item id collection to be selected / deselected
+         *
+         * @throws IllegalArgumentException
+         *             if at least one item id doesn't exist in the container of
+         *             Grid
+         */
+        protected void checkItemIdsExist(Collection<?> itemIds)
+                throws IllegalArgumentException {
+            for (Object itemId : itemIds) {
+                checkItemIdExists(itemId);
+            }
+        }
+
+        /**
+         * Fires a {@link SelectionEvent} to all the {@link SelectionListener
+         * SelectionListeners} currently added to the Grid in which this
+         * SelectionModel is.
+         * <p>
+         * Note that this is only a helper method, and routes the call all the
+         * way to Grid. A {@link SelectionModel} is not a
+         * {@link SelectionNotifier}
+         *
+         * @param oldSelection
+         *            the complete {@link Collection} of the itemIds that were
+         *            selected <em>before</em> this event happened
+         * @param newSelection
+         *            the complete {@link Collection} of the itemIds that are
+         *            selected <em>after</em> this event happened
+         */
+        protected void fireSelectionEvent(final Collection<Object> oldSelection,
+                final Collection<Object> newSelection) {
+            getParentGrid().fireSelectionEvent(oldSelection, newSelection);
+        }
+
+        @Override
+        public void generateData(Object itemId, Item item, JsonObject rowData) {
+            if (isSelected(itemId)) {
+                rowData.put(GridState.JSONKEY_SELECTED, true);
+            }
+        }
+
+        @Override
+        public void destroyData(Object itemId) {
+            // NO-OP
+        }
+
+        @Override
+        protected Object getItemId(String rowKey) {
+            return rowKey != null ? super.getItemId(rowKey) : null;
+        }
+    }
+
+    /**
+     * A default implementation of a {@link SelectionModel.Single}
+     */
+    public static class SingleSelectionModel extends AbstractSelectionModel
+            implements SelectionModel.Single {
+
+        @Override
+        protected void extend(AbstractClientConnector target) {
+            super.extend(target);
+            registerRpc(new SingleSelectionModelServerRpc() {
+
+                @Override
+                public void select(String rowKey) {
+                    SingleSelectionModel.this.select(getItemId(rowKey), false);
+                }
+            });
+        }
+
+        @Override
+        public boolean select(final Object itemId) {
+            return select(itemId, true);
+        }
+
+        protected boolean select(final Object itemId, boolean refresh) {
+            if (itemId == null) {
+                return deselect(getSelectedRow());
+            }
+
+            checkItemIdExists(itemId);
+
+            final Object selectedRow = getSelectedRow();
+            final boolean modified = selection.add(itemId);
+            if (modified) {
+                final Collection<Object> deselected;
+                if (selectedRow != null) {
+                    deselectInternal(selectedRow, false, true);
+                    deselected = Collections.singleton(selectedRow);
+                } else {
+                    deselected = Collections.emptySet();
+                }
+
+                fireSelectionEvent(deselected, selection);
+            }
+
+            if (refresh) {
+                refreshRow(itemId);
+            }
+
+            return modified;
+        }
+
+        private boolean deselect(final Object itemId) {
+            return deselectInternal(itemId, true, true);
+        }
+
+        private boolean deselectInternal(final Object itemId,
+                boolean fireEventIfNeeded, boolean refresh) {
+            final boolean modified = selection.remove(itemId);
+            if (modified) {
+                if (refresh) {
+                    refreshRow(itemId);
+                }
+                if (fireEventIfNeeded) {
+                    fireSelectionEvent(Collections.singleton(itemId),
+                            Collections.emptySet());
+                }
+            }
+            return modified;
+        }
+
+        @Override
+        public Object getSelectedRow() {
+            if (selection.isEmpty()) {
+                return null;
+            } else {
+                return selection.iterator().next();
+            }
+        }
+
+        /**
+         * Resets the selection state.
+         * <p>
+         * If an item is selected, it will become deselected.
+         */
+        @Override
+        public void reset() {
+            deselect(getSelectedRow());
+        }
+
+        @Override
+        public void setDeselectAllowed(boolean deselectAllowed) {
+            getState().deselectAllowed = deselectAllowed;
+        }
+
+        @Override
+        public boolean isDeselectAllowed() {
+            return getState().deselectAllowed;
+        }
+
+        @Override
+        protected SingleSelectionModelState getState() {
+            return (SingleSelectionModelState) super.getState();
+        }
+    }
+
+    /**
+     * A default implementation for a {@link SelectionModel.None}
+     */
+    public static class NoSelectionModel extends AbstractSelectionModel
+            implements SelectionModel.None {
+
+        @Override
+        public boolean isSelected(final Object itemId) {
+            return false;
+        }
+
+        @Override
+        public Collection<Object> getSelectedRows() {
+            return Collections.emptyList();
+        }
+
+        /**
+         * Semantically resets the selection model.
+         * <p>
+         * Effectively a no-op.
+         */
+        @Override
+        public void reset() {
+            // NOOP
+        }
+    }
+
+    /**
+     * A default implementation of a {@link SelectionModel.Multi}
+     */
+    public static class MultiSelectionModel extends AbstractSelectionModel
+            implements SelectionModel.Multi {
+
+        /**
+         * The default selection size limit.
+         *
+         * @see #setSelectionLimit(int)
+         */
+        public static final int DEFAULT_MAX_SELECTIONS = 1000;
+
+        private int selectionLimit = DEFAULT_MAX_SELECTIONS;
+
+        @Override
+        protected void extend(AbstractClientConnector target) {
+            super.extend(target);
+            registerRpc(new MultiSelectionModelServerRpc() {
+
+                @Override
+                public void select(List<String> rowKeys) {
+                    List<Object> items = new ArrayList<>();
+                    for (String rowKey : rowKeys) {
+                        items.add(getItemId(rowKey));
+                    }
+                    MultiSelectionModel.this.select(items, false);
+                }
+
+                @Override
+                public void deselect(List<String> rowKeys) {
+                    List<Object> items = new ArrayList<>();
+                    for (String rowKey : rowKeys) {
+                        items.add(getItemId(rowKey));
+                    }
+                    MultiSelectionModel.this.deselect(items, false);
+                }
+
+                @Override
+                public void selectAll() {
+                    MultiSelectionModel.this.selectAll(false);
+                }
+
+                @Override
+                public void deselectAll() {
+                    MultiSelectionModel.this.deselectAll(false);
+                }
+            });
+        }
+
+        @Override
+        public boolean select(final Object... itemIds)
+                throws IllegalArgumentException {
+            if (itemIds != null) {
+                // select will fire the event
+                return select(Arrays.asList(itemIds));
+            } else {
+                throw new IllegalArgumentException(
+                        "Vararg array of itemIds may not be null");
+            }
+        }
+
+        /**
+         * {@inheritDoc}
+         * <p>
+         * All items might not be selected if the limit set using
+         * {@link #setSelectionLimit(int)} is exceeded.
+         */
+        @Override
+        public boolean select(final Collection<?> itemIds)
+                throws IllegalArgumentException {
+            return select(itemIds, true);
+        }
+
+        protected boolean select(final Collection<?> itemIds, boolean refresh) {
+            if (itemIds == null) {
+                throw new IllegalArgumentException("itemIds may not be null");
+            }
+
+            // Sanity check
+            checkItemIdsExist(itemIds);
+
+            final boolean selectionWillChange = !selection.containsAll(itemIds)
+                    && selection.size() < selectionLimit;
+            if (selectionWillChange) {
+                final HashSet<Object> oldSelection = new HashSet<>(selection);
+                if (selection.size() + itemIds.size() >= selectionLimit) {
+                    // Add one at a time if there's a risk of overflow
+                    Iterator<?> iterator = itemIds.iterator();
+                    while (iterator.hasNext()
+                            && selection.size() < selectionLimit) {
+                        selection.add(iterator.next());
+                    }
+                } else {
+                    selection.addAll(itemIds);
+                }
+                fireSelectionEvent(oldSelection, selection);
+            }
+
+            updateAllSelectedState();
+
+            if (refresh) {
+                for (Object itemId : itemIds) {
+                    refreshRow(itemId);
+                }
+            }
+
+            return selectionWillChange;
+        }
+
+        /**
+         * Sets the maximum number of rows that can be selected at once. This is
+         * a mechanism to prevent exhausting server memory in situations where
+         * users select lots of rows. If the limit is reached, newly selected
+         * rows will not become recorded.
+         * <p>
+         * Old selections are not discarded if the current number of selected
+         * row exceeds the new limit.
+         * <p>
+         * The default limit is {@value #DEFAULT_MAX_SELECTIONS} rows.
+         *
+         * @param selectionLimit
+         *            the non-negative selection limit to set
+         * @throws IllegalArgumentException
+         *             if the limit is negative
+         */
+        public void setSelectionLimit(int selectionLimit) {
+            if (selectionLimit < 0) {
+                throw new IllegalArgumentException(
+                        "The selection limit must be non-negative");
+            }
+            this.selectionLimit = selectionLimit;
+        }
+
+        /**
+         * Gets the selection limit.
+         *
+         * @see #setSelectionLimit(int)
+         *
+         * @return the selection limit
+         */
+        public int getSelectionLimit() {
+            return selectionLimit;
+        }
+
+        @Override
+        public boolean deselect(final Object... itemIds)
+                throws IllegalArgumentException {
+            if (itemIds != null) {
+                // deselect will fire the event
+                return deselect(Arrays.asList(itemIds));
+            } else {
+                throw new IllegalArgumentException(
+                        "Vararg array of itemIds may not be null");
+            }
+        }
+
+        @Override
+        public boolean deselect(final Collection<?> itemIds)
+                throws IllegalArgumentException {
+            return deselect(itemIds, true);
+        }
+
+        protected boolean deselect(final Collection<?> itemIds,
+                boolean refresh) {
+            if (itemIds == null) {
+                throw new IllegalArgumentException("itemIds may not be null");
+            }
+
+            final boolean hasCommonElements = !Collections.disjoint(itemIds,
+                    selection);
+            if (hasCommonElements) {
+                final HashSet<Object> oldSelection = new HashSet<>(selection);
+                selection.removeAll(itemIds);
+                fireSelectionEvent(oldSelection, selection);
+            }
+
+            updateAllSelectedState();
+
+            if (refresh) {
+                for (Object itemId : itemIds) {
+                    refreshRow(itemId);
+                }
+            }
+
+            return hasCommonElements;
+        }
+
+        @Override
+        public boolean selectAll() {
+            return selectAll(true);
+        }
+
+        protected boolean selectAll(boolean refresh) {
+            // select will fire the event
+            final Indexed container = getParentGrid().getContainerDataSource();
+            if (container != null) {
+                return select(container.getItemIds(), refresh);
+            } else if (selection.isEmpty()) {
+                return false;
+            } else {
+                /*
+                 * this should never happen (no container but has a selection),
+                 * but I guess the only theoretically correct course of
+                 * action...
+                 */
+                return deselectAll(false);
+            }
+        }
+
+        @Override
+        public boolean deselectAll() {
+            return deselectAll(true);
+        }
+
+        protected boolean deselectAll(boolean refresh) {
+            // deselect will fire the event
+            return deselect(getSelectedRows(), refresh);
+        }
+
+        /**
+         * {@inheritDoc}
+         * <p>
+         * The returned Collection is in <strong>order of selection</strong>
+         * &ndash; the item that was first selected will be first in the
+         * collection, and so on. Should an item have been selected twice
+         * without being deselected in between, it will have remained in its
+         * original position.
+         */
+        @Override
+        public Collection<Object> getSelectedRows() {
+            // overridden only for JavaDoc
+            return super.getSelectedRows();
+        }
+
+        /**
+         * Resets the selection model.
+         * <p>
+         * Equivalent to calling {@link #deselectAll()}
+         */
+        @Override
+        public void reset() {
+            deselectAll();
+        }
+
+        @Override
+        public boolean setSelected(Collection<?> itemIds)
+                throws IllegalArgumentException {
+            if (itemIds == null) {
+                throw new IllegalArgumentException("itemIds may not be null");
+            }
+
+            checkItemIdsExist(itemIds);
+
+            boolean changed = false;
+            Set<Object> selectedRows = new HashSet<>(itemIds);
+            final Collection<Object> oldSelection = getSelectedRows();
+            Set<Object> added = getDifference(selectedRows, selection);
+            if (!added.isEmpty()) {
+                changed = true;
+                selection.addAll(added);
+                for (Object id : added) {
+                    refreshRow(id);
+                }
+            }
+
+            Set<Object> removed = getDifference(selection, selectedRows);
+            if (!removed.isEmpty()) {
+                changed = true;
+                selection.removeAll(removed);
+                for (Object id : removed) {
+                    refreshRow(id);
+                }
+            }
+
+            if (changed) {
+                fireSelectionEvent(oldSelection, selection);
+            }
+
+            updateAllSelectedState();
+
+            return changed;
+        }
+
+        /**
+         * Compares two sets and returns a set containing all values that are
+         * present in the first, but not in the second.
+         *
+         * @param set1
+         *            first item set
+         * @param set2
+         *            second item set
+         * @return all values from set1 which are not present in set2
+         */
+        private static Set<Object> getDifference(Set<Object> set1,
+                Set<Object> set2) {
+            Set<Object> diff = new HashSet<>(set1);
+            diff.removeAll(set2);
+            return diff;
+        }
+
+        @Override
+        public boolean setSelected(Object... itemIds)
+                throws IllegalArgumentException {
+            if (itemIds != null) {
+                return setSelected(Arrays.asList(itemIds));
+            } else {
+                throw new IllegalArgumentException(
+                        "Vararg array of itemIds may not be null");
+            }
+        }
+
+        private void updateAllSelectedState() {
+            int totalRowCount = getParentGrid().datasource.size();
+            int rows = Math.min(totalRowCount, selectionLimit);
+            if (getState().allSelected != selection.size() >= rows) {
+                getState().allSelected = selection.size() >= rows;
+            }
+        }
+
+        @Override
+        protected MultiSelectionModelState getState() {
+            return (MultiSelectionModelState) super.getState();
+        }
+    }
+
+    /**
+     * A data class which contains information which identifies a row in a
+     * {@link LegacyGrid}.
+     * <p>
+     * Since this class follows the <code>Flyweight</code>-pattern any instance
+     * of this object is subject to change without the user knowing it and so
+     * should not be stored anywhere outside of the method providing these
+     * instances.
+     */
+    public static class RowReference implements Serializable {
+        private final LegacyGrid grid;
+
+        private Object itemId;
+
+        /**
+         * Creates a new row reference for the given grid.
+         *
+         * @param grid
+         *            the grid that the row belongs to
+         */
+        public RowReference(LegacyGrid grid) {
+            this.grid = grid;
+        }
+
+        /**
+         * Sets the identifying information for this row
+         *
+         * @param itemId
+         *            the item id of the row
+         */
+        public void set(Object itemId) {
+            this.itemId = itemId;
+        }
+
+        /**
+         * Gets the grid that contains the referenced row.
+         *
+         * @return the grid that contains referenced row
+         */
+        public LegacyGrid getGrid() {
+            return grid;
+        }
+
+        /**
+         * Gets the item id of the row.
+         *
+         * @return the item id of the row
+         */
+        public Object getItemId() {
+            return itemId;
+        }
+
+        /**
+         * Gets the item for the row.
+         *
+         * @return the item for the row
+         */
+        public Item getItem() {
+            return grid.getContainerDataSource().getItem(itemId);
+        }
+    }
+
+    /**
+     * A data class which contains information which identifies a cell in a
+     * {@link LegacyGrid}.
+     * <p>
+     * Since this class follows the <code>Flyweight</code>-pattern any instance
+     * of this object is subject to change without the user knowing it and so
+     * should not be stored anywhere outside of the method providing these
+     * instances.
+     */
+    public static class CellReference implements Serializable {
+        private final RowReference rowReference;
+
+        private Object propertyId;
+
+        public CellReference(RowReference rowReference) {
+            this.rowReference = rowReference;
+        }
+
+        /**
+         * Sets the identifying information for this cell
+         *
+         * @param propertyId
+         *            the property id of the column
+         */
+        public void set(Object propertyId) {
+            this.propertyId = propertyId;
+        }
+
+        /**
+         * Gets the grid that contains the referenced cell.
+         *
+         * @return the grid that contains referenced cell
+         */
+        public LegacyGrid getGrid() {
+            return rowReference.getGrid();
+        }
+
+        /**
+         * @return the property id of the column
+         */
+        public Object getPropertyId() {
+            return propertyId;
+        }
+
+        /**
+         * @return the property for the cell
+         */
+        public Property<?> getProperty() {
+            return getItem().getItemProperty(propertyId);
+        }
+
+        /**
+         * Gets the item id of the row of the cell.
+         *
+         * @return the item id of the row
+         */
+        public Object getItemId() {
+            return rowReference.getItemId();
+        }
+
+        /**
+         * Gets the item for the row of the cell.
+         *
+         * @return the item for the row
+         */
+        public Item getItem() {
+            return rowReference.getItem();
+        }
+
+        /**
+         * Gets the value of the cell.
+         *
+         * @return the value of the cell
+         */
+        public Object getValue() {
+            return getProperty().getValue();
+        }
+    }
+
+    /**
+     * A callback interface for generating custom style names for Grid rows.
+     *
+     * @see LegacyGrid#setRowStyleGenerator(RowStyleGenerator)
+     */
+    public interface RowStyleGenerator extends Serializable {
+
+        /**
+         * Called by Grid to generate a style name for a row.
+         *
+         * @param row
+         *            the row to generate a style for
+         * @return the style name to add to this row, or {@code null} to not set
+         *         any style
+         */
+        public String getStyle(RowReference row);
+    }
+
+    /**
+     * A callback interface for generating custom style names for Grid cells.
+     *
+     * @see LegacyGrid#setCellStyleGenerator(CellStyleGenerator)
+     */
+    public interface CellStyleGenerator extends Serializable {
+
+        /**
+         * Called by Grid to generate a style name for a column.
+         *
+         * @param cell
+         *            the cell to generate a style for
+         * @return the style name to add to this cell, or {@code null} to not
+         *         set any style
+         */
+        public String getStyle(CellReference cell);
+    }
+
+    /**
+     * A callback interface for generating optional descriptions (tooltips) for
+     * Grid rows. If a description is generated for a row, it is used for all
+     * the cells in the row for which a {@link CellDescriptionGenerator cell
+     * description} is not generated.
+     *
+     * @see LegacyGrid#setRowDescriptionGenerator
+     *
+     * @since 7.6
+     */
+    public interface RowDescriptionGenerator extends Serializable {
+
+        /**
+         * Called by Grid to generate a description (tooltip) for a row. The
+         * description may contain HTML which is rendered directly; if this is
+         * not desired the returned string must be escaped by the implementing
+         * method.
+         *
+         * @param row
+         *            the row to generate a description for
+         * @return the row description or {@code null} for no description
+         */
+        public String getDescription(RowReference row);
+    }
+
+    /**
+     * A callback interface for generating optional descriptions (tooltips) for
+     * Grid cells. If a cell has both a {@link RowDescriptionGenerator row
+     * description} and a cell description, the latter has precedence.
+     *
+     * @see LegacyGrid#setCellDescriptionGenerator(CellDescriptionGenerator)
+     *
+     * @since 7.6
+     */
+    public interface CellDescriptionGenerator extends Serializable {
+
+        /**
+         * Called by Grid to generate a description (tooltip) for a cell. The
+         * description may contain HTML which is rendered directly; if this is
+         * not desired the returned string must be escaped by the implementing
+         * method.
+         *
+         * @param cell
+         *            the cell to generate a description for
+         * @return the cell description or {@code null} for no description
+         */
+        public String getDescription(CellReference cell);
+    }
+
+    /**
+     * Class for generating all row and cell related data for the essential
+     * parts of Grid.
+     */
+    private class RowDataGenerator implements DataGenerator {
+
+        private void put(String key, String value, JsonObject object) {
+            if (value != null && !value.isEmpty()) {
+                object.put(key, value);
+            }
+        }
+
+        @Override
+        public void generateData(Object itemId, Item item, JsonObject rowData) {
+            RowReference row = new RowReference(LegacyGrid.this);
+            row.set(itemId);
+
+            if (rowStyleGenerator != null) {
+                String style = rowStyleGenerator.getStyle(row);
+                put(GridState.JSONKEY_ROWSTYLE, style, rowData);
+            }
+
+            if (rowDescriptionGenerator != null) {
+                String description = rowDescriptionGenerator
+                        .getDescription(row);
+                put(GridState.JSONKEY_ROWDESCRIPTION, description, rowData);
+
+            }
+
+            JsonObject cellStyles = Json.createObject();
+            JsonObject cellData = Json.createObject();
+            JsonObject cellDescriptions = Json.createObject();
+
+            CellReference cell = new CellReference(row);
+
+            for (Column column : getColumns()) {
+                cell.set(column.getPropertyId());
+
+                writeData(cell, cellData);
+                writeStyles(cell, cellStyles);
+                writeDescriptions(cell, cellDescriptions);
+            }
+
+            if (cellDescriptionGenerator != null
+                    && cellDescriptions.keys().length > 0) {
+                rowData.put(GridState.JSONKEY_CELLDESCRIPTION,
+                        cellDescriptions);
+            }
+
+            if (cellStyleGenerator != null && cellStyles.keys().length > 0) {
+                rowData.put(GridState.JSONKEY_CELLSTYLES, cellStyles);
+            }
+
+            rowData.put(GridState.JSONKEY_DATA, cellData);
+        }
+
+        private void writeStyles(CellReference cell, JsonObject styles) {
+            if (cellStyleGenerator != null) {
+                String style = cellStyleGenerator.getStyle(cell);
+                put(columnKeys.key(cell.getPropertyId()), style, styles);
+            }
+        }
+
+        private void writeDescriptions(CellReference cell,
+                JsonObject descriptions) {
+            if (cellDescriptionGenerator != null) {
+                String description = cellDescriptionGenerator
+                        .getDescription(cell);
+                put(columnKeys.key(cell.getPropertyId()), description,
+                        descriptions);
+            }
+        }
+
+        private void writeData(CellReference cell, JsonObject data) {
+            Column column = getColumn(cell.getPropertyId());
+            LegacyConverter<?, ?> converter = column.getConverter();
+            Renderer<?> renderer = column.getRenderer();
+
+            Item item = cell.getItem();
+            Object modelValue = item.getItemProperty(cell.getPropertyId())
+                    .getValue();
+
+            data.put(columnKeys.key(cell.getPropertyId()), AbstractRenderer
+                    .encodeValue(modelValue, renderer, converter, getLocale()));
+        }
+
+        @Override
+        public void destroyData(Object itemId) {
+            // NO-OP
+        }
+    }
+
+    /**
+     * Abstract base class for Grid header and footer sections.
+     *
+     * @since 7.6
+     * @param <ROWTYPE>
+     *            the type of the rows in the section
+     */
+    public abstract static class StaticSection<ROWTYPE extends StaticSection.StaticRow<?>>
+            implements Serializable {
+
+        /**
+         * Abstract base class for Grid header and footer rows.
+         *
+         * @param <CELLTYPE>
+         *            the type of the cells in the row
+         */
+        public abstract static class StaticRow<CELLTYPE extends StaticCell>
+                implements Serializable {
+
+            private RowState rowState = new RowState();
+            protected StaticSection<?> section;
+            private Map<Object, CELLTYPE> cells = new LinkedHashMap<>();
+            private Map<Set<CELLTYPE>, CELLTYPE> cellGroups = new HashMap<>();
+
+            protected StaticRow(StaticSection<?> section) {
+                this.section = section;
+            }
+
+            protected void addCell(Object propertyId) {
+                CELLTYPE cell = createCell();
+                cell.setColumnId(
+                        section.grid.getColumn(propertyId).getState().id);
+                cells.put(propertyId, cell);
+                rowState.cells.add(cell.getCellState());
+            }
+
+            protected void removeCell(Object propertyId) {
+                CELLTYPE cell = cells.remove(propertyId);
+                if (cell != null) {
+                    Set<CELLTYPE> cellGroupForCell = getCellGroupForCell(cell);
+                    if (cellGroupForCell != null) {
+                        removeCellFromGroup(cell, cellGroupForCell);
+                    }
+                    rowState.cells.remove(cell.getCellState());
+                }
+            }
+
+            private void removeCellFromGroup(CELLTYPE cell,
+                    Set<CELLTYPE> cellGroup) {
+                String columnId = cell.getColumnId();
+                for (Set<String> group : rowState.cellGroups.keySet()) {
+                    if (group.contains(columnId)) {
+                        if (group.size() > 2) {
+                            // Update map key correctly
+                            CELLTYPE mergedCell = cellGroups.remove(cellGroup);
+                            cellGroup.remove(cell);
+                            cellGroups.put(cellGroup, mergedCell);
+
+                            group.remove(columnId);
+                        } else {
+                            rowState.cellGroups.remove(group);
+                            cellGroups.remove(cellGroup);
+                        }
+                        return;
+                    }
+                }
+            }
+
+            /**
+             * Creates and returns a new instance of the cell type.
+             *
+             * @return the created cell
+             */
+            protected abstract CELLTYPE createCell();
+
+            protected RowState getRowState() {
+                return rowState;
+            }
+
+            /**
+             * Returns the cell for the given property id on this row. If the
+             * column is merged returned cell is the cell for the whole group.
+             *
+             * @param propertyId
+             *            the property id of the column
+             * @return the cell for the given property, merged cell for merged
+             *         properties, null if not found
+             */
+            public CELLTYPE getCell(Object propertyId) {
+                CELLTYPE cell = cells.get(propertyId);
+                Set<CELLTYPE> cellGroup = getCellGroupForCell(cell);
+                if (cellGroup != null) {
+                    cell = cellGroups.get(cellGroup);
+                }
+                return cell;
+            }
+
+            /**
+             * Merges columns cells in a row
+             *
+             * @param propertyIds
+             *            The property ids of columns to merge
+             * @return The remaining visible cell after the merge
+             */
+            public CELLTYPE join(Object... propertyIds) {
+                assert propertyIds.length > 1 : "You need to merge at least 2 properties";
+
+                Set<CELLTYPE> cells = new HashSet<>();
+                for (int i = 0; i < propertyIds.length; ++i) {
+                    cells.add(getCell(propertyIds[i]));
+                }
+
+                return join(cells);
+            }
+
+            /**
+             * Merges columns cells in a row
+             *
+             * @param cells
+             *            The cells to merge. Must be from the same row.
+             * @return The remaining visible cell after the merge
+             */
+            public CELLTYPE join(CELLTYPE... cells) {
+                assert cells.length > 1 : "You need to merge at least 2 cells";
+
+                return join(new HashSet<>(Arrays.asList(cells)));
+            }
+
+            protected CELLTYPE join(Set<CELLTYPE> cells) {
+                for (CELLTYPE cell : cells) {
+                    if (getCellGroupForCell(cell) != null) {
+                        throw new IllegalArgumentException(
+                                "Cell already merged");
+                    } else if (!this.cells.containsValue(cell)) {
+                        throw new IllegalArgumentException(
+                                "Cell does not exist on this row");
+                    }
+                }
+
+                // Create new cell data for the group
+                CELLTYPE newCell = createCell();
+
+                Set<String> columnGroup = new HashSet<>();
+                for (CELLTYPE cell : cells) {
+                    columnGroup.add(cell.getColumnId());
+                }
+                rowState.cellGroups.put(columnGroup, newCell.getCellState());
+                cellGroups.put(cells, newCell);
+                return newCell;
+            }
+
+            private Set<CELLTYPE> getCellGroupForCell(CELLTYPE cell) {
+                for (Set<CELLTYPE> group : cellGroups.keySet()) {
+                    if (group.contains(cell)) {
+                        return group;
+                    }
+                }
+                return null;
+            }
+
+            /**
+             * Returns the custom style name for this row.
+             *
+             * @return the style name or null if no style name has been set
+             */
+            public String getStyleName() {
+                return getRowState().styleName;
+            }
+
+            /**
+             * Sets a custom style name for this row.
+             *
+             * @param styleName
+             *            the style name to set or null to not use any style
+             *            name
+             */
+            public void setStyleName(String styleName) {
+                getRowState().styleName = styleName;
+            }
+
+            /**
+             * Writes the declarative design to the given table row element.
+             *
+             * @since 7.5.0
+             * @param trElement
+             *            Element to write design to
+             * @param designContext
+             *            the design context
+             */
+            protected void writeDesign(Element trElement,
+                    DesignContext designContext) {
+                Set<CELLTYPE> visited = new HashSet<>();
+                for (LegacyGrid.Column column : section.grid.getColumns()) {
+                    CELLTYPE cell = getCell(column.getPropertyId());
+                    if (visited.contains(cell)) {
+                        continue;
+                    }
+                    visited.add(cell);
+
+                    Element cellElement = trElement
+                            .appendElement(getCellTagName());
+                    cell.writeDesign(cellElement, designContext);
+
+                    for (Entry<Set<CELLTYPE>, CELLTYPE> entry : cellGroups
+                            .entrySet()) {
+                        if (entry.getValue() == cell) {
+                            cellElement.attr("colspan",
+                                    "" + entry.getKey().size());
+                            break;
+                        }
+                    }
+                }
+            }
+
+            /**
+             * Reads the declarative design from the given table row element.
+             *
+             * @since 7.5.0
+             * @param trElement
+             *            Element to read design from
+             * @param designContext
+             *            the design context
+             * @throws DesignException
+             *             if the given table row contains unexpected children
+             */
+            protected void readDesign(Element trElement,
+                    DesignContext designContext) throws DesignException {
+                Elements cellElements = trElement.children();
+                int totalColSpans = 0;
+                for (int i = 0; i < cellElements.size(); ++i) {
+                    Element element = cellElements.get(i);
+                    if (!element.tagName().equals(getCellTagName())) {
+                        throw new DesignException(
+                                "Unexpected element in tr while expecting "
+                                        + getCellTagName() + ": "
+                                        + element.tagName());
+                    }
+
+                    int columnIndex = i + totalColSpans;
+
+                    int colspan = DesignAttributeHandler.readAttribute(
+                            "colspan", element.attributes(), 1, int.class);
+
+                    Set<CELLTYPE> cells = new HashSet<>();
+                    for (int c = 0; c < colspan; ++c) {
+                        cells.add(getCell(section.grid.getColumns()
+                                .get(columnIndex + c).getPropertyId()));
+                    }
+
+                    if (colspan > 1) {
+                        totalColSpans += colspan - 1;
+                        join(cells).readDesign(element, designContext);
+                    } else {
+                        cells.iterator().next().readDesign(element,
+                                designContext);
+                    }
+                }
+            }
+
+            abstract protected String getCellTagName();
+
+            void detach() {
+                for (CELLTYPE cell : cells.values()) {
+                    cell.detach();
+                }
+            }
+        }
+
+        /**
+         * A header or footer cell. Has a simple textual caption.
+         */
+        abstract static class StaticCell implements Serializable {
+
+            private CellState cellState = new CellState();
+            private StaticRow<?> row;
+
+            protected StaticCell(StaticRow<?> row) {
+                this.row = row;
+            }
+
+            void setColumnId(String id) {
+                cellState.columnId = id;
+            }
+
+            String getColumnId() {
+                return cellState.columnId;
+            }
+
+            /**
+             * Gets the row where this cell is.
+             *
+             * @return row for this cell
+             */
+            public StaticRow<?> getRow() {
+                return row;
+            }
+
+            protected CellState getCellState() {
+                return cellState;
+            }
+
+            /**
+             * Sets the text displayed in this cell.
+             *
+             * @param text
+             *            a plain text caption
+             */
+            public void setText(String text) {
+                removeComponentIfPresent();
+                cellState.text = text;
+                cellState.type = GridStaticCellType.TEXT;
+                row.section.markAsDirty();
+            }
+
+            /**
+             * Returns the text displayed in this cell.
+             *
+             * @return the plain text caption
+             */
+            public String getText() {
+                if (cellState.type != GridStaticCellType.TEXT) {
+                    throw new IllegalStateException(
+                            "Cannot fetch Text from a cell with type "
+                                    + cellState.type);
+                }
+                return cellState.text;
+            }
+
+            /**
+             * Returns the HTML content displayed in this cell.
+             *
+             * @return the html
+             *
+             */
+            public String getHtml() {
+                if (cellState.type != GridStaticCellType.HTML) {
+                    throw new IllegalStateException(
+                            "Cannot fetch HTML from a cell with type "
+                                    + cellState.type);
+                }
+                return cellState.html;
+            }
+
+            /**
+             * Sets the HTML content displayed in this cell.
+             *
+             * @param html
+             *            the html to set
+             */
+            public void setHtml(String html) {
+                removeComponentIfPresent();
+                cellState.html = html;
+                cellState.type = GridStaticCellType.HTML;
+                row.section.markAsDirty();
+            }
+
+            /**
+             * Returns the component displayed in this cell.
+             *
+             * @return the component
+             */
+            public Component getComponent() {
+                if (cellState.type != GridStaticCellType.WIDGET) {
+                    throw new IllegalStateException(
+                            "Cannot fetch Component from a cell with type "
+                                    + cellState.type);
+                }
+                return (Component) cellState.connector;
+            }
+
+            /**
+             * Sets the component displayed in this cell.
+             *
+             * @param component
+             *            the component to set
+             */
+            public void setComponent(Component component) {
+                removeComponentIfPresent();
+                component.setParent(row.section.grid);
+                cellState.connector = component;
+                cellState.type = GridStaticCellType.WIDGET;
+                row.section.markAsDirty();
+            }
+
+            /**
+             * Returns the type of content stored in this cell.
+             *
+             * @return cell content type
+             */
+            public GridStaticCellType getCellType() {
+                return cellState.type;
+            }
+
+            /**
+             * Returns the custom style name for this cell.
+             *
+             * @return the style name or null if no style name has been set
+             */
+            public String getStyleName() {
+                return cellState.styleName;
+            }
+
+            /**
+             * Sets a custom style name for this cell.
+             *
+             * @param styleName
+             *            the style name to set or null to not use any style
+             *            name
+             */
+            public void setStyleName(String styleName) {
+                cellState.styleName = styleName;
+                row.section.markAsDirty();
+            }
+
+            private void removeComponentIfPresent() {
+                Component component = (Component) cellState.connector;
+                if (component != null) {
+                    component.setParent(null);
+                    cellState.connector = null;
+                }
+            }
+
+            /**
+             * Writes the declarative design to the given table cell element.
+             *
+             * @since 7.5.0
+             * @param cellElement
+             *            Element to write design to
+             * @param designContext
+             *            the design context
+             */
+            protected void writeDesign(Element cellElement,
+                    DesignContext designContext) {
+                switch (cellState.type) {
+                case TEXT:
+                    cellElement.attr("plain-text", true);
+                    cellElement.appendText(getText());
+                    break;
+                case HTML:
+                    cellElement.append(getHtml());
+                    break;
+                case WIDGET:
+                    cellElement.appendChild(
+                            designContext.createElement(getComponent()));
+                    break;
+                }
+            }
+
+            /**
+             * Reads the declarative design from the given table cell element.
+             *
+             * @since 7.5.0
+             * @param cellElement
+             *            Element to read design from
+             * @param designContext
+             *            the design context
+             */
+            protected void readDesign(Element cellElement,
+                    DesignContext designContext) {
+                if (!cellElement.hasAttr("plain-text")) {
+                    if (cellElement.children().size() > 0
+                            && cellElement.child(0).tagName().contains("-")) {
+                        setComponent(
+                                designContext.readDesign(cellElement.child(0)));
+                    } else {
+                        setHtml(cellElement.html());
+                    }
+                } else {
+                    // text – need to unescape HTML entities
+                    setText(DesignFormatter
+                            .decodeFromTextNode(cellElement.html()));
+                }
+            }
+
+            void detach() {
+                removeComponentIfPresent();
+            }
+        }
+
+        protected LegacyGrid grid;
+        protected List<ROWTYPE> rows = new ArrayList<>();
+
+        /**
+         * Sets the visibility of the whole section.
+         *
+         * @param visible
+         *            true to show this section, false to hide
+         */
+        public void setVisible(boolean visible) {
+            if (getSectionState().visible != visible) {
+                getSectionState().visible = visible;
+                markAsDirty();
+            }
+        }
+
+        /**
+         * Returns the visibility of this section.
+         *
+         * @return true if visible, false otherwise.
+         */
+        public boolean isVisible() {
+            return getSectionState().visible;
+        }
+
+        /**
+         * Removes the row at the given position.
+         *
+         * @param rowIndex
+         *            the position of the row
+         *
+         * @throws IllegalArgumentException
+         *             if no row exists at given index
+         * @see #removeRow(StaticRow)
+         * @see #addRowAt(int)
+         * @see #appendRow()
+         * @see #prependRow()
+         */
+        public ROWTYPE removeRow(int rowIndex) {
+            if (rowIndex >= rows.size() || rowIndex < 0) {
+                throw new IllegalArgumentException(
+                        "No row at given index " + rowIndex);
+            }
+            ROWTYPE row = rows.remove(rowIndex);
+            row.detach();
+            getSectionState().rows.remove(rowIndex);
+
+            markAsDirty();
+            return row;
+        }
+
+        /**
+         * Removes the given row from the section.
+         *
+         * @param row
+         *            the row to be removed
+         *
+         * @throws IllegalArgumentException
+         *             if the row does not exist in this section
+         * @see #removeRow(int)
+         * @see #addRowAt(int)
+         * @see #appendRow()
+         * @see #prependRow()
+         */
+        public void removeRow(ROWTYPE row) {
+            try {
+                removeRow(rows.indexOf(row));
+            } catch (IndexOutOfBoundsException e) {
+                throw new IllegalArgumentException(
+                        "Section does not contain the given row");
+            }
+        }
+
+        /**
+         * Gets row at given index.
+         *
+         * @param rowIndex
+         *            0 based index for row. Counted from top to bottom
+         * @return row at given index
+         */
+        public ROWTYPE getRow(int rowIndex) {
+            if (rowIndex >= rows.size() || rowIndex < 0) {
+                throw new IllegalArgumentException(
+                        "No row at given index " + rowIndex);
+            }
+            return rows.get(rowIndex);
+        }
+
+        /**
+         * Adds a new row at the top of this section.
+         *
+         * @return the new row
+         * @see #appendRow()
+         * @see #addRowAt(int)
+         * @see #removeRow(StaticRow)
+         * @see #removeRow(int)
+         */
+        public ROWTYPE prependRow() {
+            return addRowAt(0);
+        }
+
+        /**
+         * Adds a new row at the bottom of this section.
+         *
+         * @return the new row
+         * @see #prependRow()
+         * @see #addRowAt(int)
+         * @see #removeRow(StaticRow)
+         * @see #removeRow(int)
+         */
+        public ROWTYPE appendRow() {
+            return addRowAt(rows.size());
+        }
+
+        /**
+         * Inserts a new row at the given position.
+         *
+         * @param index
+         *            the position at which to insert the row
+         * @return the new row
+         *
+         * @throws IndexOutOfBoundsException
+         *             if the index is out of bounds
+         * @see #appendRow()
+         * @see #prependRow()
+         * @see #removeRow(StaticRow)
+         * @see #removeRow(int)
+         */
+        public ROWTYPE addRowAt(int index) {
+            if (index > rows.size() || index < 0) {
+                throw new IllegalArgumentException(
+                        "Unable to add row at index " + index);
+            }
+            ROWTYPE row = createRow();
+            rows.add(index, row);
+            getSectionState().rows.add(index, row.getRowState());
+
+            for (Object id : grid.columns.keySet()) {
+                row.addCell(id);
+            }
+
+            markAsDirty();
+            return row;
+        }
+
+        /**
+         * Gets the amount of rows in this section.
+         *
+         * @return row count
+         */
+        public int getRowCount() {
+            return rows.size();
+        }
+
+        protected abstract GridStaticSectionState getSectionState();
+
+        protected abstract ROWTYPE createRow();
+
+        /**
+         * Informs the grid that state has changed and it should be redrawn.
+         */
+        protected void markAsDirty() {
+            grid.markAsDirty();
+        }
+
+        /**
+         * Removes a column for given property id from the section.
+         *
+         * @param propertyId
+         *            property to be removed
+         */
+        protected void removeColumn(Object propertyId) {
+            for (ROWTYPE row : rows) {
+                row.removeCell(propertyId);
+            }
+        }
+
+        /**
+         * Adds a column for given property id to the section.
+         *
+         * @param propertyId
+         *            property to be added
+         */
+        protected void addColumn(Object propertyId) {
+            for (ROWTYPE row : rows) {
+                row.addCell(propertyId);
+            }
+        }
+
+        /**
+         * Performs a sanity check that section is in correct state.
+         *
+         * @throws IllegalStateException
+         *             if merged cells are not i n continuous range
+         */
+        protected void sanityCheck() throws IllegalStateException {
+            List<String> columnOrder = grid.getState().columnOrder;
+            for (ROWTYPE row : rows) {
+                for (Set<String> cellGroup : row.getRowState().cellGroups
+                        .keySet()) {
+                    if (!checkCellGroupAndOrder(columnOrder, cellGroup)) {
+                        throw new IllegalStateException(
+                                "Not all merged cells were in a continuous range.");
+                    }
+                }
+            }
+        }
+
+        private boolean checkCellGroupAndOrder(List<String> columnOrder,
+                Set<String> cellGroup) {
+            if (!columnOrder.containsAll(cellGroup)) {
+                return false;
+            }
+
+            for (int i = 0; i < columnOrder.size(); ++i) {
+                if (!cellGroup.contains(columnOrder.get(i))) {
+                    continue;
+                }
+
+                for (int j = 1; j < cellGroup.size(); ++j) {
+                    if (!cellGroup.contains(columnOrder.get(i + j))) {
+                        return false;
+                    }
+                }
+                return true;
+            }
+            return false;
+        }
+
+        /**
+         * Writes the declarative design to the given table section element.
+         *
+         * @since 7.5.0
+         * @param tableSectionElement
+         *            Element to write design to
+         * @param designContext
+         *            the design context
+         */
+        protected void writeDesign(Element tableSectionElement,
+                DesignContext designContext) {
+            for (ROWTYPE row : rows) {
+                row.writeDesign(tableSectionElement.appendElement("tr"),
+                        designContext);
+            }
+        }
+
+        /**
+         * Writes the declarative design from the given table section element.
+         *
+         * @since 7.5.0
+         * @param tableSectionElement
+         *            Element to read design from
+         * @param designContext
+         *            the design context
+         * @throws DesignException
+         *             if the table section contains unexpected children
+         */
+        protected void readDesign(Element tableSectionElement,
+                DesignContext designContext) throws DesignException {
+            while (rows.size() > 0) {
+                removeRow(0);
+            }
+
+            for (Element row : tableSectionElement.children()) {
+                if (!row.tagName().equals("tr")) {
+                    throw new DesignException("Unexpected element in "
+                            + tableSectionElement.tagName() + ": "
+                            + row.tagName());
+                }
+                appendRow().readDesign(row, designContext);
+            }
+        }
+    }
+
+    /**
+     * Represents the header section of a Grid.
+     */
+    protected static class Header extends StaticSection<HeaderRow> {
+
+        private HeaderRow defaultRow = null;
+        private final GridStaticSectionState headerState = new GridStaticSectionState();
+
+        protected Header(LegacyGrid grid) {
+            this.grid = grid;
+            grid.getState(true).header = headerState;
+            HeaderRow row = createRow();
+            rows.add(row);
+            setDefaultRow(row);
+            getSectionState().rows.add(row.getRowState());
+        }
+
+        /**
+         * Sets the default row of this header. The default row is a special
+         * header row providing a user interface for sorting columns.
+         *
+         * @param row
+         *            the new default row, or null for no default row
+         *
+         * @throws IllegalArgumentException
+         *             this header does not contain the row
+         */
+        public void setDefaultRow(HeaderRow row) {
+            if (row == defaultRow) {
+                return;
+            }
+
+            if (row != null && !rows.contains(row)) {
+                throw new IllegalArgumentException(
+                        "Cannot set a default row that does not exist in the section");
+            }
+
+            if (defaultRow != null) {
+                defaultRow.setDefaultRow(false);
+            }
+
+            if (row != null) {
+                row.setDefaultRow(true);
+            }
+
+            defaultRow = row;
+            markAsDirty();
+        }
+
+        /**
+         * Returns the current default row of this header. The default row is a
+         * special header row providing a user interface for sorting columns.
+         *
+         * @return the default row or null if no default row set
+         */
+        public HeaderRow getDefaultRow() {
+            return defaultRow;
+        }
+
+        @Override
+        protected GridStaticSectionState getSectionState() {
+            return headerState;
+        }
+
+        @Override
+        protected HeaderRow createRow() {
+            return new HeaderRow(this);
+        }
+
+        @Override
+        public HeaderRow removeRow(int rowIndex) {
+            HeaderRow row = super.removeRow(rowIndex);
+            if (row == defaultRow) {
+                // Default Header Row was just removed.
+                setDefaultRow(null);
+            }
+            return row;
+        }
+
+        @Override
+        protected void sanityCheck() throws IllegalStateException {
+            super.sanityCheck();
+
+            boolean hasDefaultRow = false;
+            for (HeaderRow row : rows) {
+                if (row.getRowState().defaultRow) {
+                    if (!hasDefaultRow) {
+                        hasDefaultRow = true;
+                    } else {
+                        throw new IllegalStateException(
+                                "Multiple default rows in header");
+                    }
+                }
+            }
+        }
+
+        @Override
+        protected void readDesign(Element tableSectionElement,
+                DesignContext designContext) {
+            super.readDesign(tableSectionElement, designContext);
+
+            if (defaultRow == null && !rows.isEmpty()) {
+                grid.setDefaultHeaderRow(rows.get(0));
+            }
+        }
+    }
+
+    /**
+     * Represents a header row in Grid.
+     */
+    public static class HeaderRow extends StaticSection.StaticRow<HeaderCell> {
+
+        protected HeaderRow(StaticSection<?> section) {
+            super(section);
+        }
+
+        private void setDefaultRow(boolean value) {
+            getRowState().defaultRow = value;
+        }
+
+        private boolean isDefaultRow() {
+            return getRowState().defaultRow;
+        }
+
+        @Override
+        protected HeaderCell createCell() {
+            return new HeaderCell(this);
+        }
+
+        @Override
+        protected String getCellTagName() {
+            return "th";
+        }
+
+        @Override
+        protected void writeDesign(Element trElement,
+                DesignContext designContext) {
+            super.writeDesign(trElement, designContext);
+
+            if (section.grid.getDefaultHeaderRow() == this) {
+                DesignAttributeHandler.writeAttribute("default",
+                        trElement.attributes(), true, null, boolean.class);
+            }
+        }
+
+        @Override
+        protected void readDesign(Element trElement,
+                DesignContext designContext) {
+            super.readDesign(trElement, designContext);
+
+            boolean defaultRow = DesignAttributeHandler.readAttribute("default",
+                    trElement.attributes(), false, boolean.class);
+            if (defaultRow) {
+                section.grid.setDefaultHeaderRow(this);
+            }
+        }
+    }
+
+    /**
+     * Represents a header cell in Grid. Can be a merged cell for multiple
+     * columns.
+     */
+    public static class HeaderCell extends StaticSection.StaticCell {
+
+        protected HeaderCell(HeaderRow row) {
+            super(row);
+        }
+    }
+
+    /**
+     * Represents the footer section of a Grid. By default Footer is not
+     * visible.
+     */
+    protected static class Footer extends StaticSection<FooterRow> {
+
+        private final GridStaticSectionState footerState = new GridStaticSectionState();
+
+        protected Footer(LegacyGrid grid) {
+            this.grid = grid;
+            grid.getState(true).footer = footerState;
+        }
+
+        @Override
+        protected GridStaticSectionState getSectionState() {
+            return footerState;
+        }
+
+        @Override
+        protected FooterRow createRow() {
+            return new FooterRow(this);
+        }
+
+        @Override
+        protected void sanityCheck() throws IllegalStateException {
+            super.sanityCheck();
+        }
+    }
+
+    /**
+     * Represents a footer row in Grid.
+     */
+    public static class FooterRow extends StaticSection.StaticRow<FooterCell> {
+
+        protected FooterRow(StaticSection<?> section) {
+            super(section);
+        }
+
+        @Override
+        protected FooterCell createCell() {
+            return new FooterCell(this);
+        }
+
+        @Override
+        protected String getCellTagName() {
+            return "td";
+        }
+
+    }
+
+    /**
+     * Represents a footer cell in Grid.
+     */
+    public static class FooterCell extends StaticSection.StaticCell {
+
+        protected FooterCell(FooterRow row) {
+            super(row);
+        }
+    }
+
+    /**
+     * A column in the grid. Can be obtained by calling
+     * {@link LegacyGrid#getColumn(Object propertyId)}.
+     */
+    public static class Column implements Serializable {
+
+        /**
+         * The state of the column shared to the client
+         */
+        private final GridColumnState state;
+
+        /**
+         * The grid this column is associated with
+         */
+        private final LegacyGrid grid;
+
+        /**
+         * Backing property for column
+         */
+        private final Object propertyId;
+
+        private LegacyConverter<?, Object> converter;
+
+        /**
+         * A check for allowing the
+         * {@link #Column(LegacyGrid, GridColumnState, Object) constructor} to call
+         * {@link #setConverter(LegacyConverter)} with a <code>null</code>, even
+         * if model and renderer aren't compatible.
+         */
+        private boolean isFirstConverterAssignment = true;
+
+        /**
+         * Internally used constructor.
+         *
+         * @param grid
+         *            The grid this column belongs to. Should not be null.
+         * @param state
+         *            the shared state of this column
+         * @param propertyId
+         *            the backing property id for this column
+         */
+        Column(LegacyGrid grid, GridColumnState state, Object propertyId) {
+            this.grid = grid;
+            this.state = state;
+            this.propertyId = propertyId;
+            internalSetRenderer(new TextRenderer());
+        }
+
+        /**
+         * Returns the serializable state of this column that is sent to the
+         * client side connector.
+         *
+         * @return the internal state of the column
+         */
+        GridColumnState getState() {
+            return state;
+        }
+
+        /**
+         * Returns the property id for the backing property of this Column
+         *
+         * @return property id
+         */
+        public Object getPropertyId() {
+            return propertyId;
+        }
+
+        /**
+         * Returns the caption of the header. By default the header caption is
+         * the property id of the column.
+         *
+         * @return the text in the default row of header.
+         *
+         * @throws IllegalStateException
+         *             if the column no longer is attached to the grid
+         */
+        public String getHeaderCaption() throws IllegalStateException {
+            checkColumnIsAttached();
+
+            return state.headerCaption;
+        }
+
+        /**
+         * Sets the caption of the header. This caption is also used as the
+         * hiding toggle caption, unless it is explicitly set via
+         * {@link #setHidingToggleCaption(String)}.
+         *
+         * @param caption
+         *            the text to show in the caption
+         * @return the column itself
+         *
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        public Column setHeaderCaption(String caption)
+                throws IllegalStateException {
+            checkColumnIsAttached();
+            if (caption == null) {
+                caption = ""; // Render null as empty
+            }
+            state.headerCaption = caption;
+
+            HeaderRow row = grid.getHeader().getDefaultRow();
+            if (row != null) {
+                row.getCell(grid.getPropertyIdByColumnId(state.id))
+                        .setText(caption);
+            }
+            return this;
+        }
+
+        /**
+         * Gets the caption of the hiding toggle for this column.
+         *
+         * @since 7.5.0
+         * @see #setHidingToggleCaption(String)
+         * @return the caption for the hiding toggle for this column
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        public String getHidingToggleCaption() throws IllegalStateException {
+            checkColumnIsAttached();
+            return state.hidingToggleCaption;
+        }
+
+        /**
+         * Sets the caption of the hiding toggle for this column. Shown in the
+         * toggle for this column in the grid's sidebar when the column is
+         * {@link #isHidable() hidable}.
+         * <p>
+         * The default value is <code>null</code>, and in that case the column's
+         * {@link #getHeaderCaption() header caption} is used.
+         * <p>
+         * <em>NOTE:</em> setting this to empty string might cause the hiding
+         * toggle to not render correctly.
+         *
+         * @since 7.5.0
+         * @param hidingToggleCaption
+         *            the text to show in the column hiding toggle
+         * @return the column itself
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        public Column setHidingToggleCaption(String hidingToggleCaption)
+                throws IllegalStateException {
+            checkColumnIsAttached();
+            state.hidingToggleCaption = hidingToggleCaption;
+            grid.markAsDirty();
+            return this;
+        }
+
+        /**
+         * Returns the width (in pixels). By default a column is 100px wide.
+         *
+         * @return the width in pixels of the column
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        public double getWidth() throws IllegalStateException {
+            checkColumnIsAttached();
+            return state.width;
+        }
+
+        /**
+         * Sets the width (in pixels).
+         * <p>
+         * This overrides any configuration set by any of
+         * {@link #setExpandRatio(int)}, {@link #setMinimumWidth(double)} or
+         * {@link #setMaximumWidth(double)}.
+         *
+         * @param pixelWidth
+         *            the new pixel width of the column
+         * @return the column itself
+         *
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         * @throws IllegalArgumentException
+         *             thrown if pixel width is less than zero
+         */
+        public Column setWidth(double pixelWidth)
+                throws IllegalStateException, IllegalArgumentException {
+            checkColumnIsAttached();
+            if (pixelWidth < 0) {
+                throw new IllegalArgumentException(
+                        "Pixel width should be greated than 0 (in " + toString()
+                                + ")");
+            }
+            if (state.width != pixelWidth) {
+                state.width = pixelWidth;
+                grid.markAsDirty();
+                grid.fireColumnResizeEvent(this, false);
+            }
+            return this;
+        }
+
+        /**
+         * Returns whether this column has an undefined width.
+         *
+         * @since 7.6
+         * @return whether the width is undefined
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        public boolean isWidthUndefined() {
+            checkColumnIsAttached();
+            return state.width < 0;
+        }
+
+        /**
+         * Marks the column width as undefined. An undefined width means the
+         * grid is free to resize the column based on the cell contents and
+         * available space in the grid.
+         *
+         * @return the column itself
+         */
+        public Column setWidthUndefined() {
+            checkColumnIsAttached();
+            if (!isWidthUndefined()) {
+                state.width = -1;
+                grid.markAsDirty();
+                grid.fireColumnResizeEvent(this, false);
+            }
+            return this;
+        }
+
+        /**
+         * Checks if column is attached and throws an
+         * {@link IllegalStateException} if it is not
+         *
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        protected void checkColumnIsAttached() throws IllegalStateException {
+            if (grid.getColumnByColumnId(state.id) == null) {
+                throw new IllegalStateException("Column no longer exists.");
+            }
+        }
+
+        /**
+         * Sets this column as the last frozen column in its grid.
+         *
+         * @return the column itself
+         *
+         * @throws IllegalArgumentException
+         *             if the column is no longer attached to any grid
+         * @see LegacyGrid#setFrozenColumnCount(int)
+         */
+        public Column setLastFrozenColumn() {
+            checkColumnIsAttached();
+            grid.setFrozenColumnCount(
+                    grid.getState(false).columnOrder.indexOf(getState().id)
+                            + 1);
+            return this;
+        }
+
+        /**
+         * Sets the renderer for this column.
+         * <p>
+         * If a suitable converter isn't defined explicitly, the session
+         * converter factory is used to find a compatible converter.
+         *
+         * @param renderer
+         *            the renderer to use
+         * @return the column itself
+         *
+         * @throws IllegalArgumentException
+         *             if no compatible converter could be found
+         *
+         * @see VaadinSession#getConverterFactory()
+         * @see LegacyConverterUtil#getConverter(Class, Class, VaadinSession)
+         * @see #setConverter(LegacyConverter)
+         */
+        public Column setRenderer(Renderer<?> renderer) {
+            if (!internalSetRenderer(renderer)) {
+                throw new IllegalArgumentException(
+                        "Could not find a converter for converting from the model type "
+                                + getModelType()
+                                + " to the renderer presentation type "
+                                + renderer.getPresentationType() + " (in "
+                                + toString() + ")");
+            }
+            return this;
+        }
+
+        /**
+         * Sets the renderer for this column and the converter used to convert
+         * from the property value type to the renderer presentation type.
+         *
+         * @param renderer
+         *            the renderer to use, cannot be null
+         * @param converter
+         *            the converter to use
+         * @return the column itself
+         *
+         * @throws IllegalArgumentException
+         *             if the renderer is already associated with a grid column
+         */
+        public <T> Column setRenderer(Renderer<T> renderer,
+                LegacyConverter<? extends T, ?> converter) {
+            if (renderer.getParent() != null) {
+                throw new IllegalArgumentException(
+                        "Cannot set a renderer that is already connected to a grid column (in "
+                                + toString() + ")");
+            }
+
+            if (getRenderer() != null) {
+                grid.removeExtension(getRenderer());
+            }
+
+            grid.addRenderer(renderer);
+            state.rendererConnector = renderer;
+            setConverter(converter);
+            return this;
+        }
+
+        /**
+         * Sets the converter used to convert from the property value type to
+         * the renderer presentation type.
+         *
+         * @param converter
+         *            the converter to use, or {@code null} to not use any
+         *            converters
+         * @return the column itself
+         *
+         * @throws IllegalArgumentException
+         *             if the types are not compatible
+         */
+        public Column setConverter(LegacyConverter<?, ?> converter)
+                throws IllegalArgumentException {
+            Class<?> modelType = getModelType();
+            if (converter != null) {
+                if (!converter.getModelType().isAssignableFrom(modelType)) {
+                    throw new IllegalArgumentException(
+                            "The converter model type "
+                                    + converter.getModelType()
+                                    + " is not compatible with the property type "
+                                    + modelType + " (in " + toString() + ")");
+
+                } else if (!getRenderer().getPresentationType()
+                        .isAssignableFrom(converter.getPresentationType())) {
+                    throw new IllegalArgumentException(
+                            "The converter presentation type "
+                                    + converter.getPresentationType()
+                                    + " is not compatible with the renderer presentation type "
+                                    + getRenderer().getPresentationType()
+                                    + " (in " + toString() + ")");
+                }
+            }
+
+            else {
+                /*
+                 * Since the converter is null (i.e. will be removed), we need
+                 * to know that the renderer and model are compatible. If not,
+                 * we can't allow for this to happen.
+                 *
+                 * The constructor is allowed to call this method with null
+                 * without any compatibility checks, therefore we have a special
+                 * case for it.
+                 */
+
+                Class<?> rendererPresentationType = getRenderer()
+                        .getPresentationType();
+                if (!isFirstConverterAssignment && !rendererPresentationType
+                        .isAssignableFrom(modelType)) {
+                    throw new IllegalArgumentException(
+                            "Cannot remove converter, "
+                                    + "as renderer's presentation type "
+                                    + rendererPresentationType.getName()
+                                    + " and column's " + "model "
+                                    + modelType.getName() + " type aren't "
+                                    + "directly compatible with each other (in "
+                                    + toString() + ")");
+                }
+            }
+
+            isFirstConverterAssignment = false;
+
+            @SuppressWarnings("unchecked")
+            LegacyConverter<?, Object> castConverter = (LegacyConverter<?, Object>) converter;
+            this.converter = castConverter;
+
+            return this;
+        }
+
+        /**
+         * Returns the renderer instance used by this column.
+         *
+         * @return the renderer
+         */
+        public Renderer<?> getRenderer() {
+            return (Renderer<?>) getState().rendererConnector;
+        }
+
+        /**
+         * Returns the converter instance used by this column.
+         *
+         * @return the converter
+         */
+        public LegacyConverter<?, ?> getConverter() {
+            return converter;
+        }
+
+        private <T> boolean internalSetRenderer(Renderer<T> renderer) {
+
+            LegacyConverter<? extends T, ?> converter;
+            if (isCompatibleWithProperty(renderer, getConverter())) {
+                // Use the existing converter (possibly none) if types
+                // compatible
+                converter = (LegacyConverter<? extends T, ?>) getConverter();
+            } else {
+                converter = LegacyConverterUtil.getConverter(
+                        renderer.getPresentationType(), getModelType(),
+                        getSession());
+            }
+            setRenderer(renderer, converter);
+            return isCompatibleWithProperty(renderer, converter);
+        }
+
+        private VaadinSession getSession() {
+            UI ui = grid.getUI();
+            return ui != null ? ui.getSession() : null;
+        }
+
+        private boolean isCompatibleWithProperty(Renderer<?> renderer,
+                LegacyConverter<?, ?> converter) {
+            Class<?> type;
+            if (converter == null) {
+                type = getModelType();
+            } else {
+                type = converter.getPresentationType();
+            }
+            return renderer.getPresentationType().isAssignableFrom(type);
+        }
+
+        private Class<?> getModelType() {
+            return grid.getContainerDataSource()
+                    .getType(grid.getPropertyIdByColumnId(state.id));
+        }
+
+        /**
+         * Sets whether this column is sortable by the user. The grid can be
+         * sorted by a sortable column by clicking or tapping the column's
+         * default header. Programmatic sorting using the Grid#sort methods is
+         * not affected by this setting.
+         *
+         * @param sortable
+         *            {@code true} if the user should be able to sort the
+         *            column, {@code false} otherwise
+         * @return the column itself
+         *
+         * @throws IllegalStateException
+         *             if the data source of the Grid does not implement
+         *             {@link Sortable}
+         * @throws IllegalStateException
+         *             if the data source does not support sorting by the
+         *             property associated with this column
+         */
+        public Column setSortable(boolean sortable) {
+            checkColumnIsAttached();
+
+            if (sortable) {
+                if (!(grid.datasource instanceof Sortable)) {
+                    throw new IllegalStateException("Can't set column "
+                            + toString()
+                            + " sortable. The Container of Grid does not implement Sortable");
+                } else if (!((Sortable) grid.datasource)
+                        .getSortableContainerPropertyIds()
+                        .contains(propertyId)) {
+                    throw new IllegalStateException(
+                            "Can't set column " + toString()
+                                    + " sortable. Container doesn't support sorting by property "
+                                    + propertyId);
+                }
+            }
+
+            state.sortable = sortable;
+            grid.markAsDirty();
+            return this;
+        }
+
+        /**
+         * Returns whether the user can sort the grid by this column.
+         * <p>
+         * <em>Note:</em> it is possible to sort by this column programmatically
+         * using the Grid#sort methods regardless of the returned value.
+         *
+         * @return {@code true} if the column is sortable by the user,
+         *         {@code false} otherwise
+         */
+        public boolean isSortable() {
+            return state.sortable;
+        }
+
+        @Override
+        public String toString() {
+            return getClass().getSimpleName() + "[propertyId:"
+                    + grid.getPropertyIdByColumnId(state.id) + "]";
+        }
+
+        /**
+         * Sets the ratio with which the column expands.
+         * <p>
+         * By default, all columns expand equally (treated as if all of them had
+         * an expand ratio of 1). Once at least one column gets a defined expand
+         * ratio, the implicit expand ratio is removed, and only the defined
+         * expand ratios are taken into account.
+         * <p>
+         * If a column has a defined width ({@link #setWidth(double)}), it
+         * overrides this method's effects.
+         * <p>
+         * <em>Example:</em> A grid with three columns, with expand ratios 0, 1
+         * and 2, respectively. The column with a <strong>ratio of 0 is exactly
+         * as wide as its contents requires</strong>. The column with a ratio of
+         * 1 is as wide as it needs, <strong>plus a third of any excess
+         * space</strong>, because we have 3 parts total, and this column
+         * reserves only one of those. The column with a ratio of 2, is as wide
+         * as it needs to be, <strong>plus two thirds</strong> of the excess
+         * width.
+         *
+         * @param expandRatio
+         *            the expand ratio of this column. {@code 0} to not have it
+         *            expand at all. A negative number to clear the expand
+         *            value.
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         * @see #setWidth(double)
+         */
+        public Column setExpandRatio(int expandRatio)
+                throws IllegalStateException {
+            checkColumnIsAttached();
+
+            getState().expandRatio = expandRatio;
+            grid.markAsDirty();
+            return this;
+        }
+
+        /**
+         * Returns the column's expand ratio.
+         *
+         * @return the column's expand ratio
+         * @see #setExpandRatio(int)
+         */
+        public int getExpandRatio() {
+            return getState().expandRatio;
+        }
+
+        /**
+         * Clears the expand ratio for this column.
+         * <p>
+         * Equal to calling {@link #setExpandRatio(int) setExpandRatio(-1)}
+         *
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         */
+        public Column clearExpandRatio() throws IllegalStateException {
+            return setExpandRatio(-1);
+        }
+
+        /**
+         * Sets the minimum width for this column.
+         * <p>
+         * This defines the minimum guaranteed pixel width of the column
+         * <em>when it is set to expand</em>.
+         *
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         * @see #setExpandRatio(int)
+         */
+        public Column setMinimumWidth(double pixels)
+                throws IllegalStateException {
+            checkColumnIsAttached();
+
+            final double maxwidth = getMaximumWidth();
+            if (pixels >= 0 && pixels > maxwidth && maxwidth >= 0) {
+                throw new IllegalArgumentException("New minimum width ("
+                        + pixels + ") was greater than maximum width ("
+                        + maxwidth + ")");
+            }
+            getState().minWidth = pixels;
+            grid.markAsDirty();
+            return this;
+        }
+
+        /**
+         * Return the minimum width for this column.
+         *
+         * @return the minimum width for this column
+         * @see #setMinimumWidth(double)
+         */
+        public double getMinimumWidth() {
+            return getState().minWidth;
+        }
+
+        /**
+         * Sets the maximum width for this column.
+         * <p>
+         * This defines the maximum allowed pixel width of the column <em>when
+         * it is set to expand</em>.
+         *
+         * @param pixels
+         *            the maximum width
+         * @throws IllegalStateException
+         *             if the column is no longer attached to any grid
+         * @see #setExpandRatio(int)
+         */
+        public Column setMaximumWidth(double pixels) {
+            checkColumnIsAttached();
+
+            final double minwidth = getMinimumWidth();
+            if (pixels >= 0 && pixels < minwidth && minwidth >= 0) {
+                throw new IllegalArgumentException("New maximum width ("
+                        + pixels + ") was less than minimum width (" + minwidth
+                        + ")");
+            }
+
+            getState().maxWidth = pixels;
+            grid.markAsDirty();
+            return this;
+        }
+
+        /**
+         * Returns the maximum width for this column.
+         *
+         * @return the maximum width for this column
+         * @see #setMaximumWidth(double)
+         */
+        public double getMaximumWidth() {
+            return getState().maxWidth;
+        }
+
+        /**
+         * Sets whether the properties corresponding to this column should be
+         * editable when the item editor is active. By default columns are
+         * editable.
+         * <p>
+         * Values in non-editable columns are currently not displayed when the
+         * editor is active, but this will probably change in the future. They
+         * are not automatically assigned an editor field and, if one is
+         * manually assigned, it is not used. Columns that cannot (or should
+         * not) be edited even in principle should be set non-editable.
+         *
+         * @param editable
+         *            {@code true} if this column should be editable,
+         *            {@code false} otherwise
+         * @return this column
+         *
+         * @throws IllegalStateException
+         *             if the editor is currently active
+         *
+         * @see LegacyGrid#editItem(Object)
+         * @see LegacyGrid#isEditorActive()
+         */
+        public Column setEditable(boolean editable) {
+            checkColumnIsAttached();
+            if (grid.isEditorActive()) {
+                throw new IllegalStateException(
+                        "Cannot change column editable status while the editor is active");
+            }
+            getState().editable = editable;
+            grid.markAsDirty();
+            return this;
+        }
+
+        /**
+         * Returns whether the properties corresponding to this column should be
+         * editable when the item editor is active.
+         *
+         * @return {@code true} if this column is editable, {@code false}
+         *         otherwise
+         *
+         * @see LegacyGrid#editItem(Object)
+         * @see #setEditable(boolean)
+         */
+
+        public boolean isEditable() {
+            return getState().editable;
+        }
+
+        /**
+         * Sets the field component used to edit the properties in this column
+         * when the item editor is active. If an item has not been set, then the
+         * binding is postponed until the item is set using
+         * {@link #editItem(Object)}.
+         * <p>
+         * Setting the field to <code>null</code> clears any previously set
+         * field, causing a new field to be created the next time the item
+         * editor is opened.
+         *
+         * @param editor
+         *            the editor field
+         * @return this column
+         */
+        public Column setEditorField(LegacyField<?> editor) {
+            grid.setEditorField(getPropertyId(), editor);
+            return this;
+        }
+
+        /**
+         * Returns the editor field used to edit the properties in this column
+         * when the item editor is active. Returns null if the column is not
+         * {@link Column#isEditable() editable}.
+         * <p>
+         * When {@link #editItem(Object) editItem} is called, fields are
+         * automatically created and bound for any unbound properties.
+         * <p>
+         * Getting a field before the editor has been opened depends on special
+         * support from the {@link FieldGroup} in use. Using this method with a
+         * user-provided <code>FieldGroup</code> might cause
+         * {@link com.vaadin.data.fieldgroup.FieldGroup.BindException
+         * BindException} to be thrown.
+         *
+         * @return the bound field; or <code>null</code> if the respective
+         *         column is not editable
+         *
+         * @throws IllegalArgumentException
+         *             if there is no column for the provided property id
+         * @throws FieldGroup.BindException
+         *             if no field has been configured and there is a problem
+         *             building or binding
+         */
+        public LegacyField<?> getEditorField() {
+            return grid.getEditorField(getPropertyId());
+        }
+
+        /**
+         * Hides or shows the column. By default columns are visible before
+         * explicitly hiding them.
+         *
+         * @since 7.5.0
+         * @param hidden
+         *            <code>true</code> to hide the column, <code>false</code>
+         *            to show
+         * @return this column
+         */
+        public Column setHidden(boolean hidden) {
+            if (hidden != getState().hidden) {
+                getState().hidden = hidden;
+                grid.markAsDirty();
+                grid.fireColumnVisibilityChangeEvent(this, hidden, false);
+            }
+            return this;
+        }
+
+        /**
+         * Returns whether this column is hidden. Default is {@code false}.
+         *
+         * @since 7.5.0
+         * @return <code>true</code> if the column is currently hidden,
+         *         <code>false</code> otherwise
+         */
+        public boolean isHidden() {
+            return getState().hidden;
+        }
+
+        /**
+         * Sets whether this column can be hidden by the user. Hidable columns
+         * can be hidden and shown via the sidebar menu.
+         *
+         * @since 7.5.0
+         * @param hidable
+         *            <code>true</code> iff the column may be hidable by the
+         *            user via UI interaction
+         * @return this column
+         */
+        public Column setHidable(boolean hidable) {
+            if (hidable != getState().hidable) {
+                getState().hidable = hidable;
+                grid.markAsDirty();
+            }
+            return this;
+        }
+
+        /**
+         * Returns whether this column can be hidden by the user. Default is
+         * {@code false}.
+         * <p>
+         * <em>Note:</em> the column can be programmatically hidden using
+         * {@link #setHidden(boolean)} regardless of the returned value.
+         *
+         * @since 7.5.0
+         * @return <code>true</code> if the user can hide the column,
+         *         <code>false</code> if not
+         */
+        public boolean isHidable() {
+            return getState().hidable;
+        }
+
+        /**
+         * Sets whether this column can be resized by the user.
+         *
+         * @since 7.6
+         * @param resizable
+         *            {@code true} if this column should be resizable,
+         *            {@code false} otherwise
+         */
+        public Column setResizable(boolean resizable) {
+            if (resizable != getState().resizable) {
+                getState().resizable = resizable;
+                grid.markAsDirty();
+            }
+            return this;
+        }
+
+        /**
+         * Returns whether this column can be resized by the user. Default is
+         * {@code true}.
+         * <p>
+         * <em>Note:</em> the column can be programmatically resized using
+         * {@link #setWidth(double)} and {@link #setWidthUndefined()} regardless
+         * of the returned value.
+         *
+         * @since 7.6
+         * @return {@code true} if this column is resizable, {@code false}
+         *         otherwise
+         */
+        public boolean isResizable() {
+            return getState().resizable;
+        }
+
+        /**
+         * Writes the design attributes for this column into given element.
+         *
+         * @since 7.5.0
+         *
+         * @param design
+         *            Element to write attributes into
+         *
+         * @param designContext
+         *            the design context
+         */
+        protected void writeDesign(Element design,
+                DesignContext designContext) {
+            Attributes attributes = design.attributes();
+            GridColumnState def = new GridColumnState();
+
+            DesignAttributeHandler.writeAttribute("property-id", attributes,
+                    getPropertyId(), null, Object.class);
+
+            // Sortable is a special attribute that depends on the container.
+            DesignAttributeHandler.writeAttribute("sortable", attributes,
+                    isSortable(), null, boolean.class);
+            DesignAttributeHandler.writeAttribute("editable", attributes,
+                    isEditable(), def.editable, boolean.class);
+            DesignAttributeHandler.writeAttribute("resizable", attributes,
+                    isResizable(), def.resizable, boolean.class);
+
+            DesignAttributeHandler.writeAttribute("hidable", attributes,
+                    isHidable(), def.hidable, boolean.class);
+            DesignAttributeHandler.writeAttribute("hidden", attributes,
+                    isHidden(), def.hidden, boolean.class);
+            DesignAttributeHandler.writeAttribute("hiding-toggle-caption",
+                    attributes, getHidingToggleCaption(), null, String.class);
+
+            DesignAttributeHandler.writeAttribute("width", attributes,
+                    getWidth(), def.width, Double.class);
+            DesignAttributeHandler.writeAttribute("min-width", attributes,
+                    getMinimumWidth(), def.minWidth, Double.class);
+            DesignAttributeHandler.writeAttribute("max-width", attributes,
+                    getMaximumWidth(), def.maxWidth, Double.class);
+            DesignAttributeHandler.writeAttribute("expand", attributes,
+                    getExpandRatio(), def.expandRatio, Integer.class);
+        }
+
+        /**
+         * Reads the design attributes for this column from given element.
+         *
+         * @since 7.5.0
+         * @param design
+         *            Element to read attributes from
+         * @param designContext
+         *            the design context
+         */
+        protected void readDesign(Element design, DesignContext designContext) {
+            Attributes attributes = design.attributes();
+
+            if (design.hasAttr("sortable")) {
+                setSortable(DesignAttributeHandler.readAttribute("sortable",
+                        attributes, boolean.class));
+            }
+            if (design.hasAttr("editable")) {
+                setEditable(DesignAttributeHandler.readAttribute("editable",
+                        attributes, boolean.class));
+            }
+            if (design.hasAttr("resizable")) {
+                setResizable(DesignAttributeHandler.readAttribute("resizable",
+                        attributes, boolean.class));
+            }
+
+            if (design.hasAttr("hidable")) {
+                setHidable(DesignAttributeHandler.readAttribute("hidable",
+                        attributes, boolean.class));
+            }
+            if (design.hasAttr("hidden")) {
+                setHidden(DesignAttributeHandler.readAttribute("hidden",
+                        attributes, boolean.class));
+            }
+            if (design.hasAttr("hiding-toggle-caption")) {
+                setHidingToggleCaption(DesignAttributeHandler.readAttribute(
+                        "hiding-toggle-caption", attributes, String.class));
+            }
+
+            // Read size info where necessary.
+            if (design.hasAttr("width")) {
+                setWidth(DesignAttributeHandler.readAttribute("width",
+                        attributes, Double.class));
+            }
+            if (design.hasAttr("min-width")) {
+                setMinimumWidth(DesignAttributeHandler
+                        .readAttribute("min-width", attributes, Double.class));
+            }
+            if (design.hasAttr("max-width")) {
+                setMaximumWidth(DesignAttributeHandler
+                        .readAttribute("max-width", attributes, Double.class));
+            }
+            if (design.hasAttr("expand")) {
+                if (design.attr("expand").isEmpty()) {
+                    setExpandRatio(1);
+                } else {
+                    setExpandRatio(DesignAttributeHandler.readAttribute(
+                            "expand", attributes, Integer.class));
+                }
+            }
+        }
+    }
+
+    /**
+     * An abstract base class for server-side
+     * {@link com.vaadin.ui.renderers.Renderer Grid renderers}. This class
+     * currently extends the AbstractExtension superclass, but this fact should
+     * be regarded as an implementation detail and subject to change in a future
+     * major or minor Vaadin revision.
+     *
+     * @param <T>
+     *            the type this renderer knows how to present
+     */
+    public static abstract class AbstractRenderer<T>
+            extends AbstractGridExtension implements Renderer<T> {
+
+        private final Class<T> presentationType;
+
+        private final String nullRepresentation;
+
+        protected AbstractRenderer(Class<T> presentationType,
+                String nullRepresentation) {
+            this.presentationType = presentationType;
+            this.nullRepresentation = nullRepresentation;
+        }
+
+        protected AbstractRenderer(Class<T> presentationType) {
+            this(presentationType, null);
+        }
+
+        /**
+         * This method is inherited from AbstractExtension but should never be
+         * called directly with an AbstractRenderer.
+         */
+        @Deprecated
+        @Override
+        protected Class<LegacyGrid> getSupportedParentType() {
+            return LegacyGrid.class;
+        }
+
+        /**
+         * This method is inherited from AbstractExtension but should never be
+         * called directly with an AbstractRenderer.
+         */
+        @Deprecated
+        @Override
+        protected void extend(AbstractClientConnector target) {
+            super.extend(target);
+        }
+
+        @Override
+        public Class<T> getPresentationType() {
+            return presentationType;
+        }
+
+        @Override
+        public JsonValue encode(T value) {
+            if (value == null) {
+                return encode(getNullRepresentation(), String.class);
+            } else {
+                return encode(value, getPresentationType());
+            }
+        }
+
+        /**
+         * Null representation for the renderer
+         *
+         * @return a textual representation of {@code null}
+         */
+        protected String getNullRepresentation() {
+            return nullRepresentation;
+        }
+
+        /**
+         * Encodes the given value to JSON.
+         * <p>
+         * This is a helper method that can be invoked by an
+         * {@link #encode(Object) encode(T)} override if serializing a value of
+         * type other than {@link #getPresentationType() the presentation type}
+         * is desired. For instance, a {@code Renderer<Date>} could first turn a
+         * date value into a formatted string and return
+         * {@code encode(dateString, String.class)}.
+         *
+         * @param value
+         *            the value to be encoded
+         * @param type
+         *            the type of the value
+         * @return a JSON representation of the given value
+         */
+        protected <U> JsonValue encode(U value, Class<U> type) {
+            return JsonCodec
+                    .encode(value, null, type, getUI().getConnectorTracker())
+                    .getEncodedValue();
+        }
+
+        /**
+         * Converts and encodes the given data model property value using the
+         * given converter and renderer. This method is public only for testing
+         * purposes.
+         *
+         * @since 7.6
+         * @param renderer
+         *            the renderer to use
+         * @param converter
+         *            the converter to use
+         * @param modelValue
+         *            the value to convert and encode
+         * @param locale
+         *            the locale to use in conversion
+         * @return an encoded value ready to be sent to the client
+         */
+        public static <T> JsonValue encodeValue(Object modelValue,
+                Renderer<T> renderer, LegacyConverter<?, ?> converter,
+                Locale locale) {
+            Class<T> presentationType = renderer.getPresentationType();
+            T presentationValue;
+
+            if (converter == null) {
+                try {
+                    presentationValue = presentationType.cast(modelValue);
+                } catch (ClassCastException e) {
+                    if (presentationType == String.class) {
+                        // If there is no converter, just fallback to using
+                        // toString(). modelValue can't be null as
+                        // Class.cast(null) will always succeed
+                        presentationValue = (T) modelValue.toString();
+                    } else {
+                        throw new LegacyConverter.ConversionException(
+                                "Unable to convert value of type "
+                                        + modelValue.getClass().getName()
+                                        + " to presentation type "
+                                        + presentationType.getName()
+                                        + ". No converter is set and the types are not compatible.");
+                    }
+                }
+            } else {
+                assert presentationType
+                        .isAssignableFrom(converter.getPresentationType());
+                @SuppressWarnings("unchecked")
+                LegacyConverter<T, Object> safeConverter = (LegacyConverter<T, Object>) converter;
+                presentationValue = safeConverter.convertToPresentation(
+                        modelValue, safeConverter.getPresentationType(),
+                        locale);
+            }
+
+            JsonValue encodedValue;
+            try {
+                encodedValue = renderer.encode(presentationValue);
+            } catch (Exception e) {
+                getLogger().log(Level.SEVERE, "Unable to encode data", e);
+                encodedValue = renderer.encode(null);
+            }
+
+            return encodedValue;
+        }
+
+        private static Logger getLogger() {
+            return Logger.getLogger(AbstractRenderer.class.getName());
+        }
+
+    }
+
+    /**
+     * An abstract base class for server-side Grid extensions.
+     * <p>
+     * Note: If the extension is an instance of {@link DataGenerator} it will
+     * automatically register itself to {@link RpcDataProviderExtension} of
+     * extended Grid. On remove this registration is automatically removed.
+     *
+     * @since 7.5
+     */
+    public static abstract class AbstractGridExtension
+            extends AbstractExtension {
+
+        /**
+         * Constructs a new Grid extension.
+         */
+        public AbstractGridExtension() {
+            super();
+        }
+
+        /**
+         * Constructs a new Grid extension and extends given Grid.
+         *
+         * @param grid
+         *            a grid instance
+         */
+        public AbstractGridExtension(LegacyGrid grid) {
+            super();
+            extend(grid);
+        }
+
+        @Override
+        protected void extend(AbstractClientConnector target) {
+            super.extend(target);
+
+            if (this instanceof DataGenerator) {
+                getParentGrid().datasourceExtension
+                        .addDataGenerator((DataGenerator) this);
+            }
+        }
+
+        @Override
+        public void remove() {
+            if (this instanceof DataGenerator) {
+                getParentGrid().datasourceExtension
+                        .removeDataGenerator((DataGenerator) this);
+            }
+
+            super.remove();
+        }
+
+        /**
+         * Gets the item id for a row key.
+         * <p>
+         * A key is used to identify a particular row on both a server and a
+         * client. This method can be used to get the item id for the row key
+         * that the client has sent.
+         *
+         * @param rowKey
+         *            the row key for which to retrieve an item id
+         * @return the item id corresponding to {@code key}
+         */
+        protected Object getItemId(String rowKey) {
+            return getParentGrid().getKeyMapper().get(rowKey);
+        }
+
+        /**
+         * Gets the column for a column id.
+         * <p>
+         * An id is used to identify a particular column on both a server and a
+         * client. This method can be used to get the column for the column id
+         * that the client has sent.
+         *
+         * @param columnId
+         *            the column id for which to retrieve a column
+         * @return the column corresponding to {@code columnId}
+         */
+        protected Column getColumn(String columnId) {
+            return getParentGrid().getColumnByColumnId(columnId);
+        }
+
+        /**
+         * Gets the parent Grid of the renderer.
+         *
+         * @return parent grid
+         * @throws IllegalStateException
+         *             if parent is not Grid
+         */
+        protected LegacyGrid getParentGrid() {
+            if (getParent() instanceof LegacyGrid) {
+                LegacyGrid grid = (LegacyGrid) getParent();
+                return grid;
+            } else if (getParent() == null) {
+                throw new IllegalStateException(
+                        "Renderer is not attached to any parent");
+            } else {
+                throw new IllegalStateException(
+                        "Renderers can be used only with Grid. Extended "
+                                + getParent().getClass().getSimpleName()
+                                + " instead");
+            }
+        }
+
+        /**
+         * Resends the row data for given item id to the client.
+         *
+         * @since 7.6
+         * @param itemId
+         *            row to refresh
+         */
+        protected void refreshRow(Object itemId) {
+            getParentGrid().datasourceExtension.updateRowData(itemId);
+        }
+
+        /**
+         * Informs the parent Grid that this Extension wants to add a child
+         * component to it.
+         *
+         * @since 7.6
+         * @param c
+         *            component
+         */
+        protected void addComponentToGrid(Component c) {
+            getParentGrid().addComponent(c);
+        }
+
+        /**
+         * Informs the parent Grid that this Extension wants to remove a child
+         * component from it.
+         *
+         * @since 7.6
+         * @param c
+         *            component
+         */
+        protected void removeComponentFromGrid(Component c) {
+            getParentGrid().removeComponent(c);
+        }
+    }
+
+    /**
+     * The data source attached to the grid
+     */
+    private Container.Indexed datasource;
+
+    /**
+     * Property id to column instance mapping
+     */
+    private final Map<Object, Column> columns = new HashMap<>();
+
+    /**
+     * Key generator for column server-to-client communication
+     */
+    private final KeyMapper<Object> columnKeys = new KeyMapper<>();
+
+    /**
+     * The current sort order
+     */
+    private final List<SortOrder> sortOrder = new ArrayList<>();
+
+    /**
+     * Property listener for listening to changes in data source properties.
+     */
+    private final PropertySetChangeListener propertyListener = new PropertySetChangeListener() {
+
+        @Override
+        public void containerPropertySetChange(PropertySetChangeEvent event) {
+            Collection<?> properties = new HashSet<Object>(
+                    event.getContainer().getContainerPropertyIds());
+
+            // Find columns that need to be removed.
+            List<Column> removedColumns = new LinkedList<>();
+            for (Object propertyId : columns.keySet()) {
+                if (!properties.contains(propertyId)) {
+                    removedColumns.add(getColumn(propertyId));
+                }
+            }
+
+            // Actually remove columns.
+            for (Column column : removedColumns) {
+                Object propertyId = column.getPropertyId();
+                internalRemoveColumn(propertyId);
+                columnKeys.remove(propertyId);
+            }
+            datasourceExtension.columnsRemoved(removedColumns);
+
+            // Add new columns
+            List<Column> addedColumns = new LinkedList<>();
+            for (Object propertyId : properties) {
+                if (!columns.containsKey(propertyId)) {
+                    addedColumns.add(appendColumn(propertyId));
+                }
+            }
+            datasourceExtension.columnsAdded(addedColumns);
+
+            if (getFrozenColumnCount() > columns.size()) {
+                setFrozenColumnCount(columns.size());
+            }
+
+            // Unset sortable for non-sortable columns.
+            if (datasource instanceof Sortable) {
+                Collection<?> sortables = ((Sortable) datasource)
+                        .getSortableContainerPropertyIds();
+                for (Object propertyId : columns.keySet()) {
+                    Column column = columns.get(propertyId);
+                    if (!sortables.contains(propertyId)
+                            && column.isSortable()) {
+                        column.setSortable(false);
+                    }
+                }
+            }
+        }
+    };
+
+    private final ItemSetChangeListener editorClosingItemSetListener = new ItemSetChangeListener() {
+        @Override
+        public void containerItemSetChange(ItemSetChangeEvent event) {
+            cancelEditor();
+        }
+    };
+
+    private RpcDataProviderExtension datasourceExtension;
+
+    /**
+     * The selection model that is currently in use. Never <code>null</code>
+     * after the constructor has been run.
+     */
+    private SelectionModel selectionModel;
+
+    /**
+     * Used to know whether selection change events originate from the server or
+     * the client so the selection change handler knows whether the changes
+     * should be sent to the client.
+     */
+    private boolean applyingSelectionFromClient;
+
+    private final Header header = new Header(this);
+    private final Footer footer = new Footer(this);
+
+    private Object editedItemId = null;
+    private boolean editorActive = false;
+    private FieldGroup editorFieldGroup = new CustomFieldGroup();
+
+    private CellStyleGenerator cellStyleGenerator;
+    private RowStyleGenerator rowStyleGenerator;
+
+    private CellDescriptionGenerator cellDescriptionGenerator;
+    private RowDescriptionGenerator rowDescriptionGenerator;
+
+    /**
+     * <code>true</code> if Grid is using the internal IndexedContainer created
+     * in Grid() constructor, or <code>false</code> if the user has set their
+     * own Container.
+     *
+     * @see #setContainerDataSource(Indexed)
+     * @see #LegacyGrid()
+     */
+    private boolean defaultContainer = true;
+
+    private EditorErrorHandler editorErrorHandler = new DefaultEditorErrorHandler();
+
+    private DetailComponentManager detailComponentManager = null;
+
+    private Set<Component> extensionComponents = new HashSet<>();
+
+    private static final Method SELECTION_CHANGE_METHOD = ReflectTools
+            .findMethod(SelectionListener.class, "select",
+                    SelectionEvent.class);
+
+    private static final Method SORT_ORDER_CHANGE_METHOD = ReflectTools
+            .findMethod(SortListener.class, "sort", SortEvent.class);
+
+    private static final Method COLUMN_REORDER_METHOD = ReflectTools.findMethod(
+            ColumnReorderListener.class, "columnReorder",
+            ColumnReorderEvent.class);
+
+    private static final Method COLUMN_RESIZE_METHOD = ReflectTools.findMethod(
+            ColumnResizeListener.class, "columnResize",
+            ColumnResizeEvent.class);
+
+    private static final Method COLUMN_VISIBILITY_METHOD = ReflectTools
+            .findMethod(ColumnVisibilityChangeListener.class,
+                    "columnVisibilityChanged",
+                    ColumnVisibilityChangeEvent.class);
+
+    /**
+     * Creates a new Grid with a new {@link IndexedContainer} as the data
+     * source.
+     */
+    public LegacyGrid() {
+        this(null, null);
+    }
+
+    /**
+     * Creates a new Grid using the given data source.
+     *
+     * @param dataSource
+     *            the indexed container to use as a data source
+     */
+    public LegacyGrid(final Container.Indexed dataSource) {
+        this(null, dataSource);
+    }
+
+    /**
+     * Creates a new Grid with the given caption and a new
+     * {@link IndexedContainer} data source.
+     *
+     * @param caption
+     *            the caption of the grid
+     */
+    public LegacyGrid(String caption) {
+        this(caption, null);
+    }
+
+    /**
+     * Creates a new Grid with the given caption and data source. If the data
+     * source is null, a new {@link IndexedContainer} will be used.
+     *
+     * @param caption
+     *            the caption of the grid
+     * @param dataSource
+     *            the indexed container to use as a data source
+     */
+    public LegacyGrid(String caption, Container.Indexed dataSource) {
+        if (dataSource == null) {
+            internalSetContainerDataSource(new IndexedContainer());
+        } else {
+            setContainerDataSource(dataSource);
+        }
+        setCaption(caption);
+        initGrid();
+    }
+
+    /**
+     * Grid initial setup
+     */
+    private void initGrid() {
+        setSelectionMode(getDefaultSelectionMode());
+
+        registerRpc(new GridServerRpc() {
+
+            @Override
+            public void sort(String[] columnIds, SortDirection[] directions,
+                    boolean userOriginated) {
+                assert columnIds.length == directions.length;
+
+                List<SortOrder> order = new ArrayList<>(columnIds.length);
+                for (int i = 0; i < columnIds.length; i++) {
+                    Object propertyId = getPropertyIdByColumnId(columnIds[i]);
+                    order.add(new SortOrder(propertyId, directions[i]));
+                }
+                setSortOrder(order, userOriginated);
+                if (!order.equals(getSortOrder())) {
+                    /*
+                     * Actual sort order is not what the client expects. Make
+                     * sure the client gets a state change event by clearing the
+                     * diffstate and marking as dirty
+                     */
+                    ConnectorTracker connectorTracker = getUI()
+                            .getConnectorTracker();
+                    JsonObject diffState = connectorTracker
+                            .getDiffState(LegacyGrid.this);
+                    diffState.remove("sortColumns");
+                    diffState.remove("sortDirs");
+                    markAsDirty();
+                }
+            }
+
+            @Override
+            public void itemClick(String rowKey, String columnId,
+                    MouseEventDetails details) {
+                Object itemId = getKeyMapper().get(rowKey);
+                Item item = datasource.getItem(itemId);
+                Object propertyId = getPropertyIdByColumnId(columnId);
+                fireEvent(new ItemClickEvent(LegacyGrid.this, item, itemId,
+                        propertyId, details));
+            }
+
+            @Override
+            public void columnsReordered(List<String> newColumnOrder,
+                    List<String> oldColumnOrder) {
+                final String diffStateKey = "columnOrder";
+                ConnectorTracker connectorTracker = getUI()
+                        .getConnectorTracker();
+                JsonObject diffState = connectorTracker.getDiffState(LegacyGrid.this);
+                // discard the change if the columns have been reordered from
+                // the server side, as the server side is always right
+                if (getState(false).columnOrder.equals(oldColumnOrder)) {
+                    // Don't mark as dirty since client has the state already
+                    getState(false).columnOrder = newColumnOrder;
+                    // write changes to diffState so that possible reverting the
+                    // column order is sent to client
+                    assert diffState
+                            .hasKey(diffStateKey) : "Field name has changed";
+                    Type type = null;
+                    try {
+                        type = (getState(false).getClass()
+                                .getDeclaredField(diffStateKey)
+                                .getGenericType());
+                    } catch (NoSuchFieldException e) {
+                        e.printStackTrace();
+                    } catch (SecurityException e) {
+                        e.printStackTrace();
+                    }
+                    EncodeResult encodeResult = JsonCodec.encode(
+                            getState(false).columnOrder, diffState, type,
+                            connectorTracker);
+
+                    diffState.put(diffStateKey, encodeResult.getEncodedValue());
+                    fireColumnReorderEvent(true);
+                } else {
+                    // make sure the client is reverted to the order that the
+                    // server thinks it is
+                    diffState.remove(diffStateKey);
+                    markAsDirty();
+                }
+            }
+
+            @Override
+            public void columnVisibilityChanged(String id, boolean hidden,
+                    boolean userOriginated) {
+                final Column column = getColumnByColumnId(id);
+                final GridColumnState columnState = column.getState();
+
+                if (columnState.hidden != hidden) {
+                    columnState.hidden = hidden;
+
+                    final String diffStateKey = "columns";
+                    ConnectorTracker connectorTracker = getUI()
+                            .getConnectorTracker();
+                    JsonObject diffState = connectorTracker
+                            .getDiffState(LegacyGrid.this);
+
+                    assert diffState
+                            .hasKey(diffStateKey) : "Field name has changed";
+                    Type type = null;
+                    try {
+                        type = (getState(false).getClass()
+                                .getDeclaredField(diffStateKey)
+                                .getGenericType());
+                    } catch (NoSuchFieldException e) {
+                        e.printStackTrace();
+                    } catch (SecurityException e) {
+                        e.printStackTrace();
+                    }
+                    EncodeResult encodeResult = JsonCodec.encode(
+                            getState(false).columns, diffState, type,
+                            connectorTracker);
+
+                    diffState.put(diffStateKey, encodeResult.getEncodedValue());
+
+                    fireColumnVisibilityChangeEvent(column, hidden,
+                            userOriginated);
+                }
+            }
+
+            @Override
+            public void contextClick(int rowIndex, String rowKey,
+                    String columnId, Section section,
+                    MouseEventDetails details) {
+                Object itemId = null;
+                if (rowKey != null) {
+                    itemId = getKeyMapper().get(rowKey);
+                }
+                fireEvent(new GridContextClickEvent(LegacyGrid.this, details, section,
+                        rowIndex, itemId, getPropertyIdByColumnId(columnId)));
+            }
+
+            @Override
+            public void columnResized(String id, double pixels) {
+                final Column column = getColumnByColumnId(id);
+                if (column != null && column.isResizable()) {
+                    column.getState().width = pixels;
+                    fireColumnResizeEvent(column, true);
+                    markAsDirty();
+                }
+            }
+        });
+
+        registerRpc(new EditorServerRpc() {
+
+            @Override
+            public void bind(int rowIndex) {
+                try {
+                    Object id = getContainerDataSource().getIdByIndex(rowIndex);
+
+                    final boolean opening = editedItemId == null;
+
+                    final boolean moving = !opening && !editedItemId.equals(id);
+
+                    final boolean allowMove = !isEditorBuffered()
+                            && getEditorFieldGroup().isValid();
+
+                    if (opening || !moving || allowMove) {
+                        doBind(id);
+                    } else {
+                        failBind(null);
+                    }
+                } catch (Exception e) {
+                    failBind(e);
+                }
+            }
+
+            private void doBind(Object id) {
+                editedItemId = id;
+                doEditItem();
+                getEditorRpc().confirmBind(true);
+            }
+
+            private void failBind(Exception e) {
+                if (e != null) {
+                    handleError(e);
+                }
+                getEditorRpc().confirmBind(false);
+            }
+
+            @Override
+            public void cancel(int rowIndex) {
+                try {
+                    // For future proofing even though cannot currently fail
+                    doCancelEditor();
+                } catch (Exception e) {
+                    handleError(e);
+                }
+            }
+
+            @Override
+            public void save(int rowIndex) {
+                List<String> errorColumnIds = null;
+                String errorMessage = null;
+                boolean success = false;
+                try {
+                    saveEditor();
+                    success = true;
+                } catch (CommitException e) {
+                    try {
+                        CommitErrorEvent event = new CommitErrorEvent(LegacyGrid.this,
+                                e);
+                        getEditorErrorHandler().commitError(event);
+
+                        errorMessage = event.getUserErrorMessage();
+
+                        errorColumnIds = new ArrayList<>();
+                        for (Column column : event.getErrorColumns()) {
+                            errorColumnIds.add(column.state.id);
+                        }
+                    } catch (Exception ee) {
+                        // A badly written error handler can throw an exception,
+                        // which would lock up the Grid
+                        handleError(ee);
+                    }
+                } catch (Exception e) {
+                    handleError(e);
+                }
+                getEditorRpc().confirmSave(success, errorMessage,
+                        errorColumnIds);
+            }
+
+            private void handleError(Exception e) {
+                com.vaadin.server.ErrorEvent.findErrorHandler(LegacyGrid.this)
+                        .error(new ConnectorErrorEvent(LegacyGrid.this, e));
+            }
+        });
+    }
+
+    @Override
+    public void beforeClientResponse(boolean initial) {
+        try {
+            header.sanityCheck();
+            footer.sanityCheck();
+        } catch (Exception e) {
+            e.printStackTrace();
+            setComponentError(new ErrorMessage() {
+
+                @Override
+                public ErrorLevel getErrorLevel() {
+                    return ErrorLevel.CRITICAL;
+                }
+
+                @Override
+                public String getFormattedHtmlMessage() {
+                    return "Incorrectly merged cells";
+                }
+
+            });
+        }
+
+        super.beforeClientResponse(initial);
+    }
+
+    /**
+     * Sets the grid data source.
+     * <p>
+     *
+     * <strong>Note</strong> Grid columns are based on properties and try to
+     * detect a correct converter for the data type. The columns are not
+     * reinitialized automatically if the container is changed, and if the same
+     * properties are present after container change, the columns are reused.
+     * Properties with same names, but different data types will lead to
+     * unpredictable behaviour.
+     *
+     * @param container
+     *            The container data source. Cannot be null.
+     * @throws IllegalArgumentException
+     *             if the data source is null
+     */
+    public void setContainerDataSource(Container.Indexed container) {
+        defaultContainer = false;
+        internalSetContainerDataSource(container);
+    }
+
+    private void internalSetContainerDataSource(Container.Indexed container) {
+        if (container == null) {
+            throw new IllegalArgumentException(
+                    "Cannot set the datasource to null");
+        }
+        if (datasource == container) {
+            return;
+        }
+
+        // Remove old listeners
+        if (datasource instanceof PropertySetChangeNotifier) {
+            ((PropertySetChangeNotifier) datasource)
+                    .removePropertySetChangeListener(propertyListener);
+        }
+
+        if (datasourceExtension != null) {
+            removeExtension(datasourceExtension);
+        }
+
+        // Remove old DetailComponentManager
+        if (detailComponentManager != null) {
+            detailComponentManager.remove();
+        }
+
+        resetEditor();
+
+        datasource = container;
+
+        //
+        // Adjust sort order
+        //
+
+        if (container instanceof Container.Sortable) {
+
+            // If the container is sortable, go through the current sort order
+            // and match each item to the sortable properties of the new
+            // container. If the new container does not support an item in the
+            // current sort order, that item is removed from the current sort
+            // order list.
+            Collection<?> sortableProps = ((Container.Sortable) getContainerDataSource())
+                    .getSortableContainerPropertyIds();
+
+            Iterator<SortOrder> i = sortOrder.iterator();
+            while (i.hasNext()) {
+                if (!sortableProps.contains(i.next().getPropertyId())) {
+                    i.remove();
+                }
+            }
+
+            sort(false);
+        } else {
+            // Clear sorting order. Don't sort.
+            sortOrder.clear();
+        }
+
+        datasourceExtension = new RpcDataProviderExtension(container);
+        datasourceExtension.extend(this);
+        datasourceExtension.addDataGenerator(new RowDataGenerator());
+        for (Extension e : getExtensions()) {
+            if (e instanceof DataGenerator) {
+                datasourceExtension.addDataGenerator((DataGenerator) e);
+            }
+        }
+
+        if (detailComponentManager != null) {
+            detailComponentManager = new DetailComponentManager(this,
+                    detailComponentManager.getDetailsGenerator());
+        } else {
+            detailComponentManager = new DetailComponentManager(this);
+        }
+
+        /*
+         * selectionModel == null when the invocation comes from the
+         * constructor.
+         */
+        if (selectionModel != null) {
+            selectionModel.reset();
+        }
+
+        // Listen to changes in properties and remove columns if needed
+        if (datasource instanceof PropertySetChangeNotifier) {
+            ((PropertySetChangeNotifier) datasource)
+                    .addPropertySetChangeListener(propertyListener);
+        }
+
+        /*
+         * activeRowHandler will be updated by the client-side request that
+         * occurs on container change - no need to actively re-insert any
+         * ValueChangeListeners at this point.
+         */
+
+        setFrozenColumnCount(0);
+
+        if (columns.isEmpty()) {
+            // Add columns
+            for (Object propertyId : datasource.getContainerPropertyIds()) {
+                Column column = appendColumn(propertyId);
+
+                // Initial sorting is defined by container
+                if (datasource instanceof Sortable) {
+                    column.setSortable(((Sortable) datasource)
+                            .getSortableContainerPropertyIds()
+                            .contains(propertyId));
+                } else {
+                    column.setSortable(false);
+                }
+            }
+        } else {
+            Collection<?> properties = datasource.getContainerPropertyIds();
+            for (Object property : columns.keySet()) {
+                if (!properties.contains(property)) {
+                    throw new IllegalStateException(
+                            "Found at least one column in Grid that does not exist in the given container: "
+                                    + property + " with the header \""
+                                    + getColumn(property).getHeaderCaption()
+                                    + "\". "
+                                    + "Call removeAllColumns() before setContainerDataSource() if you want to reconfigure the columns based on the new container.");
+                }
+
+                if (!(datasource instanceof Sortable)
+                        || !((Sortable) datasource)
+                                .getSortableContainerPropertyIds()
+                                .contains(property)) {
+                    columns.get(property).setSortable(false);
+                }
+            }
+        }
+    }
+
+    /**
+     * Returns the grid data source.
+     *
+     * @return the container data source of the grid
+     */
+    public Container.Indexed getContainerDataSource() {
+        return datasource;
+    }
+
+    /**
+     * Returns a column based on the property id
+     *
+     * @param propertyId
+     *            the property id of the column
+     * @return the column or <code>null</code> if not found
+     */
+    public Column getColumn(Object propertyId) {
+        return columns.get(propertyId);
+    }
+
+    /**
+     * Returns a copy of currently configures columns in their current visual
+     * order in this Grid.
+     *
+     * @return unmodifiable copy of current columns in visual order
+     */
+    public List<Column> getColumns() {
+        List<Column> columns = new ArrayList<>();
+        for (String columnId : getState(false).columnOrder) {
+            columns.add(getColumnByColumnId(columnId));
+        }
+        return Collections.unmodifiableList(columns);
+    }
+
+    /**
+     * Adds a new Column to Grid. Also adds the property to container with data
+     * type String, if property for column does not exist in it. Default value
+     * for the new property is an empty String.
+     * <p>
+     * Note that adding a new property is only done for the default container
+     * that Grid sets up with the default constructor.
+     *
+     * @param propertyId
+     *            the property id of the new column
+     * @return the new column
+     *
+     * @throws IllegalStateException
+     *             if column for given property already exists in this grid
+     */
+
+    public Column addColumn(Object propertyId) throws IllegalStateException {
+        if (datasource.getContainerPropertyIds().contains(propertyId)
+                && !columns.containsKey(propertyId)) {
+            appendColumn(propertyId);
+        } else if (defaultContainer) {
+            addColumnProperty(propertyId, String.class, "");
+        } else {
+            if (columns.containsKey(propertyId)) {
+                throw new IllegalStateException(
+                        "A column for property id '" + propertyId.toString()
+                                + "' already exists in this grid");
+            } else {
+                throw new IllegalStateException(
+                        "Property id '" + propertyId.toString()
+                                + "' does not exist in the container");
+            }
+        }
+
+        // Inform the data provider of this new column.
+        Column column = getColumn(propertyId);
+        List<Column> addedColumns = new ArrayList<>();
+        addedColumns.add(column);
+        datasourceExtension.columnsAdded(addedColumns);
+
+        return column;
+    }
+
+    /**
+     * Adds a new Column to Grid. This function makes sure that the property
+     * with the given id and data type exists in the container. If property does
+     * not exists, it will be created.
+     * <p>
+     * Default value for the new property is 0 if type is Integer, Double and
+     * Float. If type is String, default value is an empty string. For all other
+     * types the default value is null.
+     * <p>
+     * Note that adding a new property is only done for the default container
+     * that Grid sets up with the default constructor.
+     *
+     * @param propertyId
+     *            the property id of the new column
+     * @param type
+     *            the data type for the new property
+     * @return the new column
+     *
+     * @throws IllegalStateException
+     *             if column for given property already exists in this grid or
+     *             property already exists in the container with wrong type
+     */
+    public Column addColumn(Object propertyId, Class<?> type) {
+        addColumnProperty(propertyId, type, null);
+        return getColumn(propertyId);
+    }
+
+    protected void addColumnProperty(Object propertyId, Class<?> type,
+            Object defaultValue) throws IllegalStateException {
+        if (!defaultContainer) {
+            throw new IllegalStateException(
+                    "Container for this Grid is not a default container from Grid() constructor");
+        }
+
+        if (!columns.containsKey(propertyId)) {
+            if (!datasource.getContainerPropertyIds().contains(propertyId)) {
+                datasource.addContainerProperty(propertyId, type, defaultValue);
+            } else {
+                Property<?> containerProperty = datasource.getContainerProperty(
+                        datasource.firstItemId(), propertyId);
+                if (containerProperty.getType() == type) {
+                    appendColumn(propertyId);
+                } else {
+                    throw new IllegalStateException(
+                            "DataSource already has the given property "
+                                    + propertyId + " with a different type");
+                }
+            }
+        } else {
+            throw new IllegalStateException(
+                    "Grid already has a column for property " + propertyId);
+        }
+    }
+
+    /**
+     * Removes all columns from this Grid.
+     */
+    public void removeAllColumns() {
+        List<Column> removed = new ArrayList<>(columns.values());
+        Set<Object> properties = new HashSet<>(columns.keySet());
+        for (Object propertyId : properties) {
+            removeColumn(propertyId);
+        }
+        datasourceExtension.columnsRemoved(removed);
+    }
+
+    /**
+     * Used internally by the {@link LegacyGrid} to get a {@link Column} by
+     * referencing its generated state id. Also used by {@link Column} to verify
+     * if it has been detached from the {@link LegacyGrid}.
+     *
+     * @param columnId
+     *            the client id generated for the column when the column is
+     *            added to the grid
+     * @return the column with the id or <code>null</code> if not found
+     */
+    Column getColumnByColumnId(String columnId) {
+        Object propertyId = getPropertyIdByColumnId(columnId);
+        return getColumn(propertyId);
+    }
+
+    /**
+     * Used internally by the {@link LegacyGrid} to get a property id by referencing
+     * the columns generated state id.
+     *
+     * @param columnId
+     *            The state id of the column
+     * @return The column instance or null if not found
+     */
+    Object getPropertyIdByColumnId(String columnId) {
+        return columnKeys.get(columnId);
+    }
+
+    /**
+     * Returns whether column reordering is allowed. Default value is
+     * <code>false</code>.
+     *
+     * @since 7.5.0
+     * @return true if reordering is allowed
+     */
+    public boolean isColumnReorderingAllowed() {
+        return getState(false).columnReorderingAllowed;
+    }
+
+    /**
+     * Sets whether or not column reordering is allowed. Default value is
+     * <code>false</code>.
+     *
+     * @since 7.5.0
+     * @param columnReorderingAllowed
+     *            specifies whether column reordering is allowed
+     */
+    public void setColumnReorderingAllowed(boolean columnReorderingAllowed) {
+        if (isColumnReorderingAllowed() != columnReorderingAllowed) {
+            getState().columnReorderingAllowed = columnReorderingAllowed;
+        }
+    }
+
+    @Override
+    protected GridState getState() {
+        return (GridState) super.getState();
+    }
+
+    @Override
+    protected GridState getState(boolean markAsDirty) {
+        return (GridState) super.getState(markAsDirty);
+    }
+
+    /**
+     * Creates a new column based on a property id and appends it as the last
+     * column.
+     *
+     * @param datasourcePropertyId
+     *            The property id of a property in the datasource
+     */
+    private Column appendColumn(Object datasourcePropertyId) {
+        if (datasourcePropertyId == null) {
+            throw new IllegalArgumentException("Property id cannot be null");
+        }
+        assert datasource.getContainerPropertyIds().contains(
+                datasourcePropertyId) : "Datasource should contain the property id";
+
+        GridColumnState columnState = new GridColumnState();
+        columnState.id = columnKeys.key(datasourcePropertyId);
+
+        Column column = new Column(this, columnState, datasourcePropertyId);
+        columns.put(datasourcePropertyId, column);
+
+        getState().columns.add(columnState);
+        getState().columnOrder.add(columnState.id);
+        header.addColumn(datasourcePropertyId);
+        footer.addColumn(datasourcePropertyId);
+
+        String humanFriendlyPropertyId = SharedUtil.propertyIdToHumanFriendly(
+                String.valueOf(datasourcePropertyId));
+        column.setHeaderCaption(humanFriendlyPropertyId);
+
+        if (datasource instanceof Sortable
+                && ((Sortable) datasource).getSortableContainerPropertyIds()
+                        .contains(datasourcePropertyId)) {
+            column.setSortable(true);
+        }
+
+        return column;
+    }
+
+    /**
+     * Removes a column from Grid based on a property id.
+     *
+     * @param propertyId
+     *            The property id of column to be removed
+     *
+     * @throws IllegalArgumentException
+     *             if there is no column for given property id in this grid
+     */
+    public void removeColumn(Object propertyId)
+            throws IllegalArgumentException {
+        if (!columns.keySet().contains(propertyId)) {
+            throw new IllegalArgumentException(
+                    "There is no column for given property id " + propertyId);
+        }
+
+        List<Column> removed = new ArrayList<>();
+        removed.add(getColumn(propertyId));
+        internalRemoveColumn(propertyId);
+        datasourceExtension.columnsRemoved(removed);
+    }
+
+    private void internalRemoveColumn(Object propertyId) {
+        setEditorField(propertyId, null);
+        header.removeColumn(propertyId);
+        footer.removeColumn(propertyId);
+        Column column = columns.remove(propertyId);
+        getState().columnOrder.remove(columnKeys.key(propertyId));
+        getState().columns.remove(column.getState());
+        removeExtension(column.getRenderer());
+    }
+
+    /**
+     * Sets the columns and their order for the grid. Current columns whose
+     * property id is not in propertyIds are removed. Similarly, a column is
+     * added for any property id in propertyIds that has no corresponding column
+     * in this Grid.
+     *
+     * @since 7.5.0
+     *
+     * @param propertyIds
+     *            properties in the desired column order
+     */
+    public void setColumns(Object... propertyIds) {
+        Set<?> removePids = new HashSet<>(columns.keySet());
+        removePids.removeAll(Arrays.asList(propertyIds));
+        for (Object removePid : removePids) {
+            removeColumn(removePid);
+        }
+        Set<?> addPids = new HashSet<>(Arrays.asList(propertyIds));
+        addPids.removeAll(columns.keySet());
+        for (Object propertyId : addPids) {
+            addColumn(propertyId);
+        }
+        setColumnOrder(propertyIds);
+    }
+
+    /**
+     * Sets a new column order for the grid. All columns which are not ordered
+     * here will remain in the order they were before as the last columns of
+     * grid.
+     *
+     * @param propertyIds
+     *            properties in the order columns should be
+     */
+    public void setColumnOrder(Object... propertyIds) {
+        List<String> columnOrder = new ArrayList<>();
+        for (Object propertyId : propertyIds) {
+            if (columns.containsKey(propertyId)) {
+                columnOrder.add(columnKeys.key(propertyId));
+            } else {
+                throw new IllegalArgumentException(
+                        "Grid does not contain column for property "
+                                + String.valueOf(propertyId));
+            }
+        }
+
+        List<String> stateColumnOrder = getState().columnOrder;
+        if (stateColumnOrder.size() != columnOrder.size()) {
+            stateColumnOrder.removeAll(columnOrder);
+            columnOrder.addAll(stateColumnOrder);
+        }
+        getState().columnOrder = columnOrder;
+        fireColumnReorderEvent(false);
+    }
+
+    /**
+     * Sets the number of frozen columns in this grid. Setting the count to 0
+     * means that no data columns will be frozen, but the built-in selection
+     * checkbox column will still be frozen if it's in use. Setting the count to
+     * -1 will also disable the selection column.
+     * <p>
+     * The default value is 0.
+     *
+     * @param numberOfColumns
+     *            the number of columns that should be frozen
+     *
+     * @throws IllegalArgumentException
+     *             if the column count is < 0 or > the number of visible columns
+     */
+    public void setFrozenColumnCount(int numberOfColumns) {
+        if (numberOfColumns < -1 || numberOfColumns > columns.size()) {
+            throw new IllegalArgumentException(
+                    "count must be between -1 and the current number of columns ("
+                            + columns.size() + "): " + numberOfColumns);
+        }
+
+        getState().frozenColumnCount = numberOfColumns;
+    }
+
+    /**
+     * Gets the number of frozen columns in this grid. 0 means that no data
+     * columns will be frozen, but the built-in selection checkbox column will
+     * still be frozen if it's in use. -1 means that not even the selection
+     * column is frozen.
+     * <p>
+     * <em>NOTE:</em> this count includes {@link Column#isHidden() hidden
+     * columns} in the count.
+     *
+     * @see #setFrozenColumnCount(int)
+     *
+     * @return the number of frozen columns
+     */
+    public int getFrozenColumnCount() {
+        return getState(false).frozenColumnCount;
+    }
+
+    /**
+     * Scrolls to a certain item, using {@link ScrollDestination#ANY}.
+     * <p>
+     * If the item has visible details, its size will also be taken into
+     * account.
+     *
+     * @param itemId
+     *            id of item to scroll to.
+     * @throws IllegalArgumentException
+     *             if the provided id is not recognized by the data source.
+     */
+    public void scrollTo(Object itemId) throws IllegalArgumentException {
+        scrollTo(itemId, ScrollDestination.ANY);
+    }
+
+    /**
+     * Scrolls to a certain item, using user-specified scroll destination.
+     * <p>
+     * If the item has visible details, its size will also be taken into
+     * account.
+     *
+     * @param itemId
+     *            id of item to scroll to.
+     * @param destination
+     *            value specifying desired position of scrolled-to row.
+     * @throws IllegalArgumentException
+     *             if the provided id is not recognized by the data source.
+     */
+    public void scrollTo(Object itemId, ScrollDestination destination)
+            throws IllegalArgumentException {
+
+        int row = datasource.indexOfId(itemId);
+
+        if (row == -1) {
+            throw new IllegalArgumentException(
+                    "Item with specified ID does not exist in data source");
+        }
+
+        GridClientRpc clientRPC = getRpcProxy(GridClientRpc.class);
+        clientRPC.scrollToRow(row, destination);
+    }
+
+    /**
+     * Scrolls to the beginning of the first data row.
+     */
+    public void scrollToStart() {
+        GridClientRpc clientRPC = getRpcProxy(GridClientRpc.class);
+        clientRPC.scrollToStart();
+    }
+
+    /**
+     * Scrolls to the end of the last data row.
+     */
+    public void scrollToEnd() {
+        GridClientRpc clientRPC = getRpcProxy(GridClientRpc.class);
+        clientRPC.scrollToEnd();
+    }
+
+    /**
+     * Sets the number of rows that should be visible in Grid's body, while
+     * {@link #getHeightMode()} is {@link HeightMode#ROW}.
+     * <p>
+     * If Grid is currently not in {@link HeightMode#ROW}, the given value is
+     * remembered, and applied once the mode is applied.
+     *
+     * @param rows
+     *            The height in terms of number of rows displayed in Grid's
+     *            body. If Grid doesn't contain enough rows, white space is
+     *            displayed instead. If <code>null</code> is given, then Grid's
+     *            height is undefined
+     * @throws IllegalArgumentException
+     *             if {@code rows} is zero or less
+     * @throws IllegalArgumentException
+     *             if {@code rows} is {@link Double#isInfinite(double) infinite}
+     * @throws IllegalArgumentException
+     *             if {@code rows} is {@link Double#isNaN(double) NaN}
+     */
+    public void setHeightByRows(double rows) {
+        if (rows <= 0.0d) {
+            throw new IllegalArgumentException(
+                    "More than zero rows must be shown.");
+        } else if (Double.isInfinite(rows)) {
+            throw new IllegalArgumentException(
+                    "Grid doesn't support infinite heights");
+        } else if (Double.isNaN(rows)) {
+            throw new IllegalArgumentException("NaN is not a valid row count");
+        }
+
+        getState().heightByRows = rows;
+    }
+
+    /**
+     * Gets the amount of rows in Grid's body that are shown, while
+     * {@link #getHeightMode()} is {@link HeightMode#ROW}.
+     *
+     * @return the amount of rows that are being shown in Grid's body
+     * @see #setHeightByRows(double)
+     */
+    public double getHeightByRows() {
+        return getState(false).heightByRows;
+    }
+
+    /**
+     * {@inheritDoc}
+     * <p>
+     * <em>Note:</em> This method will change the widget's size in the browser
+     * only if {@link #getHeightMode()} returns {@link HeightMode#CSS}.
+     *
+     * @see #setHeightMode(HeightMode)
+     */
+    @Override
+    public void setHeight(float height, Unit unit) {
+        super.setHeight(height, unit);
+    }
+
+    /**
+     * Defines the mode in which the Grid widget's height is calculated.
+     * <p>
+     * If {@link HeightMode#CSS} is given, Grid will respect the values given
+     * via a {@code setHeight}-method, and behave as a traditional Component.
+     * <p>
+     * If {@link HeightMode#ROW} is given, Grid will make sure that the body
+     * will display as many rows as {@link #getHeightByRows()} defines.
+     * <em>Note:</em> If headers/footers are inserted or removed, the widget
+     * will resize itself to still display the required amount of rows in its
+     * body. It also takes the horizontal scrollbar into account.
+     *
+     * @param heightMode
+     *            the mode in to which Grid should be set
+     */
+    public void setHeightMode(HeightMode heightMode) {
+        /*
+         * This method is a workaround for the fact that Vaadin re-applies
+         * widget dimensions (height/width) on each state change event. The
+         * original design was to have setHeight and setHeightByRow be equals,
+         * and whichever was called the latest was considered in effect.
+         *
+         * But, because of Vaadin always calling setHeight on the widget, this
+         * approach doesn't work.
+         */
+
+        getState().heightMode = heightMode;
+    }
+
+    /**
+     * Returns the current {@link HeightMode} the Grid is in.
+     * <p>
+     * Defaults to {@link HeightMode#CSS}.
+     *
+     * @return the current HeightMode
+     */
+    public HeightMode getHeightMode() {
+        return getState(false).heightMode;
+    }
+
+    /* Selection related methods: */
+
+    /**
+     * Takes a new {@link SelectionModel} into use.
+     * <p>
+     * The SelectionModel that is previously in use will have all its items
+     * deselected.
+     * <p>
+     * If the given SelectionModel is already in use, this method does nothing.
+     *
+     * @param selectionModel
+     *            the new SelectionModel to use
+     * @throws IllegalArgumentException
+     *             if {@code selectionModel} is <code>null</code>
+     */
+    public void setSelectionModel(SelectionModel selectionModel)
+            throws IllegalArgumentException {
+        if (selectionModel == null) {
+            throw new IllegalArgumentException(
+                    "Selection model may not be null");
+        }
+
+        if (this.selectionModel != selectionModel) {
+            // this.selectionModel is null on init
+            if (this.selectionModel != null) {
+                this.selectionModel.remove();
+            }
+
+            this.selectionModel = selectionModel;
+            selectionModel.setGrid(this);
+        }
+    }
+
+    /**
+     * Returns the currently used {@link SelectionModel}.
+     *
+     * @return the currently used SelectionModel
+     */
+    public SelectionModel getSelectionModel() {
+        return selectionModel;
+    }
+
+    /**
+     * Sets the Grid's selection mode.
+     * <p>
+     * Grid supports three selection modes: multiselect, single select and no
+     * selection, and this is a convenience method for choosing between one of
+     * them.
+     * <p>
+     * Technically, this method is a shortcut that can be used instead of
+     * calling {@code setSelectionModel} with a specific SelectionModel
+     * instance. Grid comes with three built-in SelectionModel classes, and the
+     * {@link SelectionMode} enum represents each of them.
+     * <p>
+     * Essentially, the two following method calls are equivalent:
+     * <p>
+     * <code><pre>
+     * grid.setSelectionMode(SelectionMode.MULTI);
+     * grid.setSelectionModel(new MultiSelectionMode());
+     * </pre></code>
+     *
+     *
+     * @param selectionMode
+     *            the selection mode to switch to
+     * @return The {@link SelectionModel} instance that was taken into use
+     * @throws IllegalArgumentException
+     *             if {@code selectionMode} is <code>null</code>
+     * @see SelectionModel
+     */
+    public SelectionModel setSelectionMode(final SelectionMode selectionMode)
+            throws IllegalArgumentException {
+        if (selectionMode == null) {
+            throw new IllegalArgumentException(
+                    "selection mode may not be null");
+        }
+        final SelectionModel newSelectionModel = selectionMode.createModel();
+        setSelectionModel(newSelectionModel);
+        return newSelectionModel;
+    }
+
+    /**
+     * Checks whether an item is selected or not.
+     *
+     * @param itemId
+     *            the item id to check for
+     * @return <code>true</code> iff the item is selected
+     */
+    // keep this javadoc in sync with SelectionModel.isSelected
+    public boolean isSelected(Object itemId) {
+        return selectionModel.isSelected(itemId);
+    }
+
+    /**
+     * Returns a collection of all the currently selected itemIds.
+     * <p>
+     * This method is a shorthand that delegates to the
+     * {@link #getSelectionModel() selection model}.
+     *
+     * @return a collection of all the currently selected itemIds
+     */
+    // keep this javadoc in sync with SelectionModel.getSelectedRows
+    public Collection<Object> getSelectedRows() {
+        return getSelectionModel().getSelectedRows();
+    }
+
+    /**
+     * Gets the item id of the currently selected item.
+     * <p>
+     * This method is a shorthand that delegates to the
+     * {@link #getSelectionModel() selection model}. Only
+     * {@link SelectionModel.Single} is supported.
+     *
+     * @return the item id of the currently selected item, or <code>null</code>
+     *         if nothing is selected
+     * @throws IllegalStateException
+     *             if the selection model does not implement
+     *             {@code SelectionModel.Single}
+     */
+    // keep this javadoc in sync with SelectionModel.Single.getSelectedRow
+    public Object getSelectedRow() throws IllegalStateException {
+        if (selectionModel instanceof SelectionModel.Single) {
+            return ((SelectionModel.Single) selectionModel).getSelectedRow();
+        } else if (selectionModel instanceof SelectionModel.Multi) {
+            throw new IllegalStateException("Cannot get unique selected row: "
+                    + "Grid is in multiselect mode "
+                    + "(the current selection model is "
+                    + selectionModel.getClass().getName() + ").");
+        } else if (selectionModel instanceof SelectionModel.None) {
+            throw new IllegalStateException(
+                    "Cannot get selected row: " + "Grid selection is disabled "
+                            + "(the current selection model is "
+                            + selectionModel.getClass().getName() + ").");
+        } else {
+            throw new IllegalStateException("Cannot get selected row: "
+                    + "Grid selection model does not implement "
+                    + SelectionModel.Single.class.getName() + " or "
+                    + SelectionModel.Multi.class.getName()
+                    + "(the current model is "
+                    + selectionModel.getClass().getName() + ").");
+        }
+    }
+
+    /**
+     * Marks an item as selected.
+     * <p>
+     * This method is a shorthand that delegates to the
+     * {@link #getSelectionModel() selection model}. Only
+     * {@link SelectionModel.Single} and {@link SelectionModel.Multi} are
+     * supported.
+     *
+     * @param itemId
+     *            the itemId to mark as selected
+     * @return <code>true</code> if the selection state changed,
+     *         <code>false</code> if the itemId already was selected
+     * @throws IllegalArgumentException
+     *             if the {@code itemId} doesn't exist in the currently active
+     *             Container
+     * @throws IllegalStateException
+     *             if the selection was illegal. One such reason might be that
+     *             the implementation already had an item selected, and that
+     *             needs to be explicitly deselected before re-selecting
+     *             something.
+     * @throws IllegalStateException
+     *             if the selection model does not implement
+     *             {@code SelectionModel.Single} or {@code SelectionModel.Multi}
+     */
+    // keep this javadoc in sync with SelectionModel.Single.select
+    public boolean select(Object itemId)
+            throws IllegalArgumentException, IllegalStateException {
+        if (selectionModel instanceof SelectionModel.Single) {
+            return ((SelectionModel.Single) selectionModel).select(itemId);
+        } else if (selectionModel instanceof SelectionModel.Multi) {
+            return ((SelectionModel.Multi) selectionModel).select(itemId);
+        } else if (selectionModel instanceof SelectionModel.None) {
+            throw new IllegalStateException("Cannot select row '" + itemId
+                    + "': Grid selection is disabled "
+                    + "(the current selection model is "
+                    + selectionModel.getClass().getName() + ").");
+        } else {
+            throw new IllegalStateException("Cannot select row '" + itemId
+                    + "': Grid selection model does not implement "
+                    + SelectionModel.Single.class.getName() + " or "
+                    + SelectionModel.Multi.class.getName()
+                    + "(the current model is "
+                    + selectionModel.getClass().getName() + ").");
+        }
+    }
+
+    /**
+     * Marks an item as unselected.
+     * <p>
+     * This method is a shorthand that delegates to the
+     * {@link #getSelectionModel() selection model}. Only
+     * {@link SelectionModel.Single} and {@link SelectionModel.Multi} are
+     * supported.
+     *
+     * @param itemId
+     *            the itemId to remove from being selected
+     * @return <code>true</code> if the selection state changed,
+     *         <code>false</code> if the itemId was already selected
+     * @throws IllegalArgumentException
+     *             if the {@code itemId} doesn't exist in the currently active
+     *             Container
+     * @throws IllegalStateException
+     *             if the deselection was illegal. One such reason might be that
+     *             the implementation requires one or more items to be selected
+     *             at all times.
+     * @throws IllegalStateException
+     *             if the selection model does not implement
+     *             {@code SelectionModel.Single} or {code SelectionModel.Multi}
+     */
+    // keep this javadoc in sync with SelectionModel.Single.deselect
+    public boolean deselect(Object itemId) throws IllegalStateException {
+        if (selectionModel instanceof SelectionModel.Single) {
+            if (isSelected(itemId)) {
+                return ((SelectionModel.Single) selectionModel).select(null);
+            }
+            return false;
+        } else if (selectionModel instanceof SelectionModel.Multi) {
+            return ((SelectionModel.Multi) selectionModel).deselect(itemId);
+        } else if (selectionModel instanceof SelectionModel.None) {
+            throw new IllegalStateException("Cannot deselect row '" + itemId
+                    + "': Grid selection is disabled "
+                    + "(the current selection model is "
+                    + selectionModel.getClass().getName() + ").");
+        } else {
+            throw new IllegalStateException("Cannot deselect row '" + itemId
+                    + "': Grid selection model does not implement "
+                    + SelectionModel.Single.class.getName() + " or "
+                    + SelectionModel.Multi.class.getName()
+                    + "(the current model is "
+                    + selectionModel.getClass().getName() + ").");
+        }
+    }
+
+    /**
+     * Marks all items as unselected.
+     * <p>
+     * This method is a shorthand that delegates to the
+     * {@link #getSelectionModel() selection model}. Only
+     * {@link SelectionModel.Single} and {@link SelectionModel.Multi} are
+     * supported.
+     *
+     * @return <code>true</code> if the selection state changed,
+     *         <code>false</code> if the itemId was already selected
+     * @throws IllegalStateException
+     *             if the deselection was illegal. One such reason might be that
+     *             the implementation requires one or more items to be selected
+     *             at all times.
+     * @throws IllegalStateException
+     *             if the selection model does not implement
+     *             {@code SelectionModel.Single} or {code SelectionModel.Multi}
+     */
+    public boolean deselectAll() throws IllegalStateException {
+        if (selectionModel instanceof SelectionModel.Single) {
+            if (getSelectedRow() != null) {
+                return deselect(getSelectedRow());
+            }
+            return false;
+        } else if (selectionModel instanceof SelectionModel.Multi) {
+            return ((SelectionModel.Multi) selectionModel).deselectAll();
+        } else if (selectionModel instanceof SelectionModel.None) {
+            throw new IllegalStateException(
+                    "Cannot deselect all rows" + ": Grid selection is disabled "
+                            + "(the current selection model is "
+                            + selectionModel.getClass().getName() + ").");
+        } else {
+            throw new IllegalStateException("Cannot deselect all rows:"
+                    + " Grid selection model does not implement "
+                    + SelectionModel.Single.class.getName() + " or "
+                    + SelectionModel.Multi.class.getName()
+                    + "(the current model is "
+                    + selectionModel.getClass().getName() + ").");
+        }
+    }
+
+    /**
+     * Fires a selection change event.
+     * <p>
+     * <strong>Note:</strong> This is not a method that should be called by
+     * application logic. This method is publicly accessible only so that
+     * {@link SelectionModel SelectionModels} would be able to inform Grid of
+     * these events.
+     *
+     * @param newSelection
+     *            the selection that was added by this event
+     * @param oldSelection
+     *            the selection that was removed by this event
+     */
+    public void fireSelectionEvent(Collection<Object> oldSelection,
+            Collection<Object> newSelection) {
+        fireEvent(new SelectionEvent(this, oldSelection, newSelection));
+    }
+
+    @Override
+    public void addSelectionListener(SelectionListener listener) {
+        addListener(SelectionEvent.class, listener, SELECTION_CHANGE_METHOD);
+    }
+
+    @Override
+    public void removeSelectionListener(SelectionListener listener) {
+        removeListener(SelectionEvent.class, listener, SELECTION_CHANGE_METHOD);
+    }
+
+    private void fireColumnReorderEvent(boolean userOriginated) {
+        fireEvent(new ColumnReorderEvent(this, userOriginated));
+    }
+
+    /**
+     * Registers a new column reorder listener.
+     *
+     * @since 7.5.0
+     * @param listener
+     *            the listener to register
+     */
+    public void addColumnReorderListener(ColumnReorderListener listener) {
+        addListener(ColumnReorderEvent.class, listener, COLUMN_REORDER_METHOD);
+    }
+
+    /**
+     * Removes a previously registered column reorder listener.
+     *
+     * @since 7.5.0
+     * @param listener
+     *            the listener to remove
+     */
+    public void removeColumnReorderListener(ColumnReorderListener listener) {
+        removeListener(ColumnReorderEvent.class, listener,
+                COLUMN_REORDER_METHOD);
+    }
+
+    private void fireColumnResizeEvent(Column column, boolean userOriginated) {
+        fireEvent(new ColumnResizeEvent(this, column, userOriginated));
+    }
+
+    /**
+     * Registers a new column resize listener.
+     *
+     * @param listener
+     *            the listener to register
+     */
+    public void addColumnResizeListener(ColumnResizeListener listener) {
+        addListener(ColumnResizeEvent.class, listener, COLUMN_RESIZE_METHOD);
+    }
+
+    /**
+     * Removes a previously registered column resize listener.
+     *
+     * @param listener
+     *            the listener to remove
+     */
+    public void removeColumnResizeListener(ColumnResizeListener listener) {
+        removeListener(ColumnResizeEvent.class, listener, COLUMN_RESIZE_METHOD);
+    }
+
+    /**
+     * Gets the {@link KeyMapper } being used by the data source.
+     *
+     * @return the key mapper being used by the data source
+     */
+    KeyMapper<Object> getKeyMapper() {
+        return datasourceExtension.getKeyMapper();
+    }
+
+    /**
+     * Adds a renderer to this grid's connector hierarchy.
+     *
+     * @param renderer
+     *            the renderer to add
+     */
+    void addRenderer(Renderer<?> renderer) {
+        addExtension(renderer);
+    }
+
+    /**
+     * Sets the current sort order using the fluid Sort API. Read the
+     * documentation for {@link Sort} for more information.
+     * <p>
+     * <em>Note:</em> Sorting by a property that has no column in Grid will hide
+     * all possible sorting indicators.
+     *
+     * @param s
+     *            a sort instance
+     *
+     * @throws IllegalStateException
+     *             if container is not sortable (does not implement
+     *             Container.Sortable)
+     * @throws IllegalArgumentException
+     *             if trying to sort by non-existing property
+     */
+    public void sort(Sort s) {
+        setSortOrder(s.build());
+    }
+
+    /**
+     * Sort this Grid in ascending order by a specified property.
+     * <p>
+     * <em>Note:</em> Sorting by a property that has no column in Grid will hide
+     * all possible sorting indicators.
+     *
+     * @param propertyId
+     *            a property ID
+     *
+     * @throws IllegalStateException
+     *             if container is not sortable (does not implement
+     *             Container.Sortable)
+     * @throws IllegalArgumentException
+     *             if trying to sort by non-existing property
+     */
+    public void sort(Object propertyId) {
+        sort(propertyId, SortDirection.ASCENDING);
+    }
+
+    /**
+     * Sort this Grid in user-specified {@link SortOrder} by a property.
+     * <p>
+     * <em>Note:</em> Sorting by a property that has no column in Grid will hide
+     * all possible sorting indicators.
+     *
+     * @param propertyId
+     *            a property ID
+     * @param direction
+     *            a sort order value (ascending/descending)
+     *
+     * @throws IllegalStateException
+     *             if container is not sortable (does not implement
+     *             Container.Sortable)
+     * @throws IllegalArgumentException
+     *             if trying to sort by non-existing property
+     */
+    public void sort(Object propertyId, SortDirection direction) {
+        sort(Sort.by(propertyId, direction));
+    }
+
+    /**
+     * Clear the current sort order, and re-sort the grid.
+     */
+    public void clearSortOrder() {
+        sortOrder.clear();
+        sort(false);
+    }
+
+    /**
+     * Sets the sort order to use.
+     * <p>
+     * <em>Note:</em> Sorting by a property that has no column in Grid will hide
+     * all possible sorting indicators.
+     *
+     * @param order
+     *            a sort order list.
+     *
+     * @throws IllegalStateException
+     *             if container is not sortable (does not implement
+     *             Container.Sortable)
+     * @throws IllegalArgumentException
+     *             if order is null or trying to sort by non-existing property
+     */
+    public void setSortOrder(List<SortOrder> order) {
+        setSortOrder(order, false);
+    }
+
+    private void setSortOrder(List<SortOrder> order, boolean userOriginated)
+            throws IllegalStateException, IllegalArgumentException {
+        if (!(getContainerDataSource() instanceof Container.Sortable)) {
+            throw new IllegalStateException(
+                    "Attached container is not sortable (does not implement Container.Sortable)");
+        }
+
+        if (order == null) {
+            throw new IllegalArgumentException("Order list may not be null!");
+        }
+
+        sortOrder.clear();
+
+        Collection<?> sortableProps = ((Container.Sortable) getContainerDataSource())
+                .getSortableContainerPropertyIds();
+
+        for (SortOrder o : order) {
+            if (!sortableProps.contains(o.getPropertyId())) {
+                throw new IllegalArgumentException("Property "
+                        + o.getPropertyId()
+                        + " does not exist or is not sortable in the current container");
+            }
+        }
+
+        sortOrder.addAll(order);
+        sort(userOriginated);
+    }
+
+    /**
+     * Get the current sort order list.
+     *
+     * @return a sort order list
+     */
+    public List<SortOrder> getSortOrder() {
+        return Collections.unmodifiableList(sortOrder);
+    }
+
+    /**
+     * Apply sorting to data source.
+     */
+    private void sort(boolean userOriginated) {
+
+        Container c = getContainerDataSource();
+        if (c instanceof Container.Sortable) {
+            Container.Sortable cs = (Container.Sortable) c;
+
+            final int items = sortOrder.size();
+            Object[] propertyIds = new Object[items];
+            boolean[] directions = new boolean[items];
+
+            SortDirection[] stateDirs = new SortDirection[items];
+
+            for (int i = 0; i < items; ++i) {
+                SortOrder order = sortOrder.get(i);
+
+                stateDirs[i] = order.getDirection();
+                propertyIds[i] = order.getPropertyId();
+                switch (order.getDirection()) {
+                case ASCENDING:
+                    directions[i] = true;
+                    break;
+                case DESCENDING:
+                    directions[i] = false;
+                    break;
+                default:
+                    throw new IllegalArgumentException("getDirection() of "
+                            + order + " returned an unexpected value");
+                }
+            }
+
+            cs.sort(propertyIds, directions);
+
+            if (columns.keySet().containsAll(Arrays.asList(propertyIds))) {
+                String[] columnKeys = new String[items];
+                for (int i = 0; i < items; ++i) {
+                    columnKeys[i] = this.columnKeys.key(propertyIds[i]);
+                }
+                getState().sortColumns = columnKeys;
+                getState(false).sortDirs = stateDirs;
+            } else {
+                // Not all sorted properties are in Grid. Remove any indicators.
+                getState().sortColumns = new String[] {};
+                getState(false).sortDirs = new SortDirection[] {};
+            }
+            fireEvent(new SortEvent(this, new ArrayList<>(sortOrder),
+                    userOriginated));
+        } else {
+            throw new IllegalStateException(
+                    "Container is not sortable (does not implement Container.Sortable)");
+        }
+    }
+
+    /**
+     * Adds a sort order change listener that gets notified when the sort order
+     * changes.
+     *
+     * @param listener
+     *            the sort order change listener to add
+     */
+    @Override
+    public void addSortListener(SortListener listener) {
+        addListener(SortEvent.class, listener, SORT_ORDER_CHANGE_METHOD);
+    }
+
+    /**
+     * Removes a sort order change listener previously added using
+     * {@link #addSortListener(SortListener)}.
+     *
+     * @param listener
+     *            the sort order change listener to remove
+     */
+    @Override
+    public void removeSortListener(SortListener listener) {
+        removeListener(SortEvent.class, listener, SORT_ORDER_CHANGE_METHOD);
+    }
+
+    /* Grid Headers */
+
+    /**
+     * Returns the header section of this grid. The default header contains a
+     * single row displaying the column captions.
+     *
+     * @return the header
+     */
+    protected Header getHeader() {
+        return header;
+    }
+
+    /**
+     * Gets the header row at given index.
+     *
+     * @param rowIndex
+     *            0 based index for row. Counted from top to bottom
+     * @return header row at given index
+     * @throws IllegalArgumentException
+     *             if no row exists at given index
+     */
+    public HeaderRow getHeaderRow(int rowIndex) {
+        return header.getRow(rowIndex);
+    }
+
+    /**
+     * Inserts a new row at the given position to the header section. Shifts the
+     * row currently at that position and any subsequent rows down (adds one to
+     * their indices).
+     *
+     * @param index
+     *            the position at which to insert the row
+     * @return the new row
+     *
+     * @throws IllegalArgumentException
+     *             if the index is less than 0 or greater than row count
+     * @see #appendHeaderRow()
+     * @see #prependHeaderRow()
+     * @see #removeHeaderRow(HeaderRow)
+     * @see #removeHeaderRow(int)
+     */
+    public HeaderRow addHeaderRowAt(int index) {
+        return header.addRowAt(index);
+    }
+
+    /**
+     * Adds a new row at the bottom of the header section.
+     *
+     * @return the new row
+     * @see #prependHeaderRow()
+     * @see #addHeaderRowAt(int)
+     * @see #removeHeaderRow(HeaderRow)
+     * @see #removeHeaderRow(int)
+     */
+    public HeaderRow appendHeaderRow() {
+        return header.appendRow();
+    }
+
+    /**
+     * Returns the current default row of the header section. The default row is
+     * a special header row providing a user interface for sorting columns.
+     * Setting a header text for column updates cells in the default header.
+     *
+     * @return the default row or null if no default row set
+     */
+    public HeaderRow getDefaultHeaderRow() {
+        return header.getDefaultRow();
+    }
+
+    /**
+     * Gets the row count for the header section.
+     *
+     * @return row count
+     */
+    public int getHeaderRowCount() {
+        return header.getRowCount();
+    }
+
+    /**
+     * Adds a new row at the top of the header section.
+     *
+     * @return the new row
+     * @see #appendHeaderRow()
+     * @see #addHeaderRowAt(int)
+     * @see #removeHeaderRow(HeaderRow)
+     * @see #removeHeaderRow(int)
+     */
+    public HeaderRow prependHeaderRow() {
+        return header.prependRow();
+    }
+
+    /**
+     * Removes the given row from the header section.
+     *
+     * @param row
+     *            the row to be removed
+     *
+     * @throws IllegalArgumentException
+     *             if the row does not exist in this section
+     * @see #removeHeaderRow(int)
+     * @see #addHeaderRowAt(int)
+     * @see #appendHeaderRow()
+     * @see #prependHeaderRow()
+     */
+    public void removeHeaderRow(HeaderRow row) {
+        header.removeRow(row);
+    }
+
+    /**
+     * Removes the row at the given position from the header section.
+     *
+     * @param rowIndex
+     *            the position of the row
+     *
+     * @throws IllegalArgumentException
+     *             if no row exists at given index
+     * @see #removeHeaderRow(HeaderRow)
+     * @see #addHeaderRowAt(int)
+     * @see #appendHeaderRow()
+     * @see #prependHeaderRow()
+     */
+    public void removeHeaderRow(int rowIndex) {
+        header.removeRow(rowIndex);
+    }
+
+    /**
+     * Sets the default row of the header. The default row is a special header
+     * row providing a user interface for sorting columns.
+     *
+     * @param row
+     *            the new default row, or null for no default row
+     *
+     * @throws IllegalArgumentException
+     *             header does not contain the row
+     */
+    public void setDefaultHeaderRow(HeaderRow row) {
+        header.setDefaultRow(row);
+    }
+
+    /**
+     * Sets the visibility of the header section.
+     *
+     * @param visible
+     *            true to show header section, false to hide
+     */
+    public void setHeaderVisible(boolean visible) {
+        header.setVisible(visible);
+    }
+
+    /**
+     * Returns the visibility of the header section.
+     *
+     * @return true if visible, false otherwise.
+     */
+    public boolean isHeaderVisible() {
+        return header.isVisible();
+    }
+
+    /* Grid Footers */
+
+    /**
+     * Returns the footer section of this grid. The default header contains a
+     * single row displaying the column captions.
+     *
+     * @return the footer
+     */
+    protected Footer getFooter() {
+        return footer;
+    }
+
+    /**
+     * Gets the footer row at given index.
+     *
+     * @param rowIndex
+     *            0 based index for row. Counted from top to bottom
+     * @return footer row at given index
+     * @throws IllegalArgumentException
+     *             if no row exists at given index
+     */
+    public FooterRow getFooterRow(int rowIndex) {
+        return footer.getRow(rowIndex);
+    }
+
+    /**
+     * Inserts a new row at the given position to the footer section. Shifts the
+     * row currently at that position and any subsequent rows down (adds one to
+     * their indices).
+     *
+     * @param index
+     *            the position at which to insert the row
+     * @return the new row
+     *
+     * @throws IllegalArgumentException
+     *             if the index is less than 0 or greater than row count
+     * @see #appendFooterRow()
+     * @see #prependFooterRow()
+     * @see #removeFooterRow(FooterRow)
+     * @see #removeFooterRow(int)
+     */
+    public FooterRow addFooterRowAt(int index) {
+        return footer.addRowAt(index);
+    }
+
+    /**
+     * Adds a new row at the bottom of the footer section.
+     *
+     * @return the new row
+     * @see #prependFooterRow()
+     * @see #addFooterRowAt(int)
+     * @see #removeFooterRow(FooterRow)
+     * @see #removeFooterRow(int)
+     */
+    public FooterRow appendFooterRow() {
+        return footer.appendRow();
+    }
+
+    /**
+     * Gets the row count for the footer.
+     *
+     * @return row count
+     */
+    public int getFooterRowCount() {
+        return footer.getRowCount();
+    }
+
+    /**
+     * Adds a new row at the top of the footer section.
+     *
+     * @return the new row
+     * @see #appendFooterRow()
+     * @see #addFooterRowAt(int)
+     * @see #removeFooterRow(FooterRow)
+     * @see #removeFooterRow(int)
+     */
+    public FooterRow prependFooterRow() {
+        return footer.prependRow();
+    }
+
+    /**
+     * Removes the given row from the footer section.
+     *
+     * @param row
+     *            the row to be removed
+     *
+     * @throws IllegalArgumentException
+     *             if the row does not exist in this section
+     * @see #removeFooterRow(int)
+     * @see #addFooterRowAt(int)
+     * @see #appendFooterRow()
+     * @see #prependFooterRow()
+     */
+    public void removeFooterRow(FooterRow row) {
+        footer.removeRow(row);
+    }
+
+    /**
+     * Removes the row at the given position from the footer section.
+     *
+     * @param rowIndex
+     *            the position of the row
+     *
+     * @throws IllegalArgumentException
+     *             if no row exists at given index
+     * @see #removeFooterRow(FooterRow)
+     * @see #addFooterRowAt(int)
+     * @see #appendFooterRow()
+     * @see #prependFooterRow()
+     */
+    public void removeFooterRow(int rowIndex) {
+        footer.removeRow(rowIndex);
+    }
+
+    /**
+     * Sets the visibility of the footer section.
+     *
+     * @param visible
+     *            true to show footer section, false to hide
+     */
+    public void setFooterVisible(boolean visible) {
+        footer.setVisible(visible);
+    }
+
+    /**
+     * Returns the visibility of the footer section.
+     *
+     * @return true if visible, false otherwise.
+     */
+    public boolean isFooterVisible() {
+        return footer.isVisible();
+    }
+
+    private void addComponent(Component c) {
+        extensionComponents.add(c);
+        c.setParent(this);
+        markAsDirty();
+    }
+
+    private void removeComponent(Component c) {
+        extensionComponents.remove(c);
+        c.setParent(null);
+        markAsDirty();
+    }
+
+    @Override
+    public Iterator<Component> iterator() {
+        // This is a hash set to avoid adding header/footer components inside
+        // merged cells multiple times
+        LinkedHashSet<Component> componentList = new LinkedHashSet<>();
+
+        Header header = getHeader();
+        for (int i = 0; i < header.getRowCount(); ++i) {
+            HeaderRow row = header.getRow(i);
+            for (Object propId : columns.keySet()) {
+                HeaderCell cell = row.getCell(propId);
+                if (cell.getCellState().type == GridStaticCellType.WIDGET) {
+                    componentList.add(cell.getComponent());
+                }
+            }
+        }
+
+        Footer footer = getFooter();
+        for (int i = 0; i < footer.getRowCount(); ++i) {
+            FooterRow row = footer.getRow(i);
+            for (Object propId : columns.keySet()) {
+                FooterCell cell = row.getCell(propId);
+                if (cell.getCellState().type == GridStaticCellType.WIDGET) {
+                    componentList.add(cell.getComponent());
+                }
+            }
+        }
+
+        componentList.addAll(getEditorFields());
+
+        componentList.addAll(extensionComponents);
+
+        return componentList.iterator();
+    }
+
+    @Override
+    public boolean isRendered(Component childComponent) {
+        if (getEditorFields().contains(childComponent)) {
+            // Only render editor fields if the editor is open
+            return isEditorActive();
+        } else {
+            // TODO Header and footer components should also only be rendered if
+            // the header/footer is visible
+            return true;
+        }
+    }
+
+    EditorClientRpc getEditorRpc() {
+        return getRpcProxy(EditorClientRpc.class);
+    }
+
+    /**
+     * Sets the {@code CellDescriptionGenerator} instance for generating
+     * optional descriptions (tooltips) for individual Grid cells. If a
+     * {@link RowDescriptionGenerator} is also set, the row description it
+     * generates is displayed for cells for which {@code generator} returns
+     * null.
+     *
+     * @param generator
+     *            the description generator to use or {@code null} to remove a
+     *            previously set generator if any
+     *
+     * @see #setRowDescriptionGenerator(RowDescriptionGenerator)
+     *
+     * @since 7.6
+     */
+    public void setCellDescriptionGenerator(
+            CellDescriptionGenerator generator) {
+        cellDescriptionGenerator = generator;
+        getState().hasDescriptions = (generator != null
+                || rowDescriptionGenerator != null);
+        datasourceExtension.refreshCache();
+    }
+
+    /**
+     * Returns the {@code CellDescriptionGenerator} instance used to generate
+     * descriptions (tooltips) for Grid cells.
+     *
+     * @return the description generator or {@code null} if no generator is set
+     *
+     * @since 7.6
+     */
+    public CellDescriptionGenerator getCellDescriptionGenerator() {
+        return cellDescriptionGenerator;
+    }
+
+    /**
+     * Sets the {@code RowDescriptionGenerator} instance for generating optional
+     * descriptions (tooltips) for Grid rows. If a
+     * {@link CellDescriptionGenerator} is also set, the row description
+     * generated by {@code generator} is used for cells for which the cell
+     * description generator returns null.
+     *
+     *
+     * @param generator
+     *            the description generator to use or {@code null} to remove a
+     *            previously set generator if any
+     *
+     * @see #setCellDescriptionGenerator(CellDescriptionGenerator)
+     *
+     * @since 7.6
+     */
+    public void setRowDescriptionGenerator(RowDescriptionGenerator generator) {
+        rowDescriptionGenerator = generator;
+        getState().hasDescriptions = (generator != null
+                || cellDescriptionGenerator != null);
+        datasourceExtension.refreshCache();
+    }
+
+    /**
+     * Returns the {@code RowDescriptionGenerator} instance used to generate
+     * descriptions (tooltips) for Grid rows
+     *
+     * @return the description generator or {@code} null if no generator is set
+     *
+     * @since 7.6
+     */
+    public RowDescriptionGenerator getRowDescriptionGenerator() {
+        return rowDescriptionGenerator;
+    }
+
+    /**
+     * Sets the style generator that is used for generating styles for cells
+     *
+     * @param cellStyleGenerator
+     *            the cell style generator to set, or <code>null</code> to
+     *            remove a previously set generator
+     */
+    public void setCellStyleGenerator(CellStyleGenerator cellStyleGenerator) {
+        this.cellStyleGenerator = cellStyleGenerator;
+        datasourceExtension.refreshCache();
+    }
+
+    /**
+     * Gets the style generator that is used for generating styles for cells
+     *
+     * @return the cell style generator, or <code>null</code> if no generator is
+     *         set
+     */
+    public CellStyleGenerator getCellStyleGenerator() {
+        return cellStyleGenerator;
+    }
+
+    /**
+     * Sets the style generator that is used for generating styles for rows
+     *
+     * @param rowStyleGenerator
+     *            the row style generator to set, or <code>null</code> to remove
+     *            a previously set generator
+     */
+    public void setRowStyleGenerator(RowStyleGenerator rowStyleGenerator) {
+        this.rowStyleGenerator = rowStyleGenerator;
+        datasourceExtension.refreshCache();
+    }
+
+    /**
+     * Gets the style generator that is used for generating styles for rows
+     *
+     * @return the row style generator, or <code>null</code> if no generator is
+     *         set
+     */
+    public RowStyleGenerator getRowStyleGenerator() {
+        return rowStyleGenerator;
+    }
+
+    /**
+     * Adds a row to the underlying container. The order of the parameters
+     * should match the current visible column order.
+     * <p>
+     * Please note that it's generally only safe to use this method during
+     * initialization. After Grid has been initialized and the visible column
+     * order might have been changed, it's better to instead add items directly
+     * to the underlying container and use {@link Item#getItemProperty(Object)}
+     * to make sure each value is assigned to the intended property.
+     *
+     * @param values
+     *            the cell values of the new row, in the same order as the
+     *            visible column order, not <code>null</code>.
+     * @return the item id of the new row
+     * @throws IllegalArgumentException
+     *             if values is null
+     * @throws IllegalArgumentException
+     *             if its length does not match the number of visible columns
+     * @throws IllegalArgumentException
+     *             if a parameter value is not an instance of the corresponding
+     *             property type
+     * @throws UnsupportedOperationException
+     *             if the container does not support adding new items
+     */
+    public Object addRow(Object... values) {
+        if (values == null) {
+            throw new IllegalArgumentException("Values cannot be null");
+        }
+
+        Indexed dataSource = getContainerDataSource();
+        List<String> columnOrder = getState(false).columnOrder;
+
+        if (values.length != columnOrder.size()) {
+            throw new IllegalArgumentException(
+                    "There are " + columnOrder.size() + " visible columns, but "
+                            + values.length + " cell values were provided.");
+        }
+
+        // First verify all parameter types
+        for (int i = 0; i < columnOrder.size(); i++) {
+            Object propertyId = getPropertyIdByColumnId(columnOrder.get(i));
+
+            Class<?> propertyType = dataSource.getType(propertyId);
+            if (values[i] != null && !propertyType.isInstance(values[i])) {
+                throw new IllegalArgumentException("Parameter " + i + "("
+                        + values[i] + ") is not an instance of "
+                        + propertyType.getCanonicalName());
+            }
+        }
+
+        Object itemId = dataSource.addItem();
+        try {
+            Item item = dataSource.getItem(itemId);
+            for (int i = 0; i < columnOrder.size(); i++) {
+                Object propertyId = getPropertyIdByColumnId(columnOrder.get(i));
+                Property<Object> property = item.getItemProperty(propertyId);
+                property.setValue(values[i]);
+            }
+        } catch (RuntimeException e) {
+            try {
+                dataSource.removeItem(itemId);
+            } catch (Exception e2) {
+                getLogger().log(Level.SEVERE,
+                        "Error recovering from exception in addRow", e);
+            }
+            throw e;
+        }
+
+        return itemId;
+    }
+
+    private static Logger getLogger() {
+        return Logger.getLogger(LegacyGrid.class.getName());
+    }
+
+    /**
+     * Sets whether or not the item editor UI is enabled for this grid. When the
+     * editor is enabled, the user can open it by double-clicking a row or
+     * hitting enter when a row is focused. The editor can also be opened
+     * programmatically using the {@link #editItem(Object)} method.
+     *
+     * @param isEnabled
+     *            <code>true</code> to enable the feature, <code>false</code>
+     *            otherwise
+     * @throws IllegalStateException
+     *             if an item is currently being edited
+     *
+     * @see #getEditedItemId()
+     */
+    public void setEditorEnabled(boolean isEnabled)
+            throws IllegalStateException {
+        if (isEditorActive()) {
+            throw new IllegalStateException(
+                    "Cannot disable the editor while an item ("
+                            + getEditedItemId() + ") is being edited");
+        }
+        if (isEditorEnabled() != isEnabled) {
+            getState().editorEnabled = isEnabled;
+        }
+    }
+
+    /**
+     * Checks whether the item editor UI is enabled for this grid.
+     *
+     * @return <code>true</code> iff the editor is enabled for this grid
+     *
+     * @see #setEditorEnabled(boolean)
+     * @see #getEditedItemId()
+     */
+    public boolean isEditorEnabled() {
+        return getState(false).editorEnabled;
+    }
+
+    /**
+     * Gets the id of the item that is currently being edited.
+     *
+     * @return the id of the item that is currently being edited, or
+     *         <code>null</code> if no item is being edited at the moment
+     */
+    public Object getEditedItemId() {
+        return editedItemId;
+    }
+
+    /**
+     * Gets the field group that is backing the item editor of this grid.
+     *
+     * @return the backing field group
+     */
+    public FieldGroup getEditorFieldGroup() {
+        return editorFieldGroup;
+    }
+
+    /**
+     * Sets the field group that is backing the item editor of this grid.
+     *
+     * @param fieldGroup
+     *            the backing field group
+     *
+     * @throws IllegalStateException
+     *             if the editor is currently active
+     */
+    public void setEditorFieldGroup(FieldGroup fieldGroup) {
+        if (isEditorActive()) {
+            throw new IllegalStateException(
+                    "Cannot change field group while an item ("
+                            + getEditedItemId() + ") is being edited");
+        }
+        editorFieldGroup = fieldGroup;
+    }
+
+    /**
+     * Returns whether an item is currently being edited in the editor.
+     *
+     * @return true iff the editor is open
+     */
+    public boolean isEditorActive() {
+        return editorActive;
+    }
+
+    private void checkColumnExists(Object propertyId) {
+        if (getColumn(propertyId) == null) {
+            throw new IllegalArgumentException(
+                    "There is no column with the property id " + propertyId);
+        }
+    }
+
+    private LegacyField<?> getEditorField(Object propertyId) {
+        checkColumnExists(propertyId);
+
+        if (!getColumn(propertyId).isEditable()) {
+            return null;
+        }
+
+        LegacyField<?> editor = editorFieldGroup.getField(propertyId);
+
+        try {
+            if (editor == null) {
+                editor = editorFieldGroup.buildAndBind(propertyId);
+            }
+        } finally {
+            if (editor == null) {
+                editor = editorFieldGroup.getField(propertyId);
+            }
+
+            if (editor != null && editor.getParent() != LegacyGrid.this) {
+                assert editor.getParent() == null;
+                editor.setParent(this);
+            }
+        }
+        return editor;
+    }
+
+    /**
+     * Opens the editor interface for the provided item. Scrolls the Grid to
+     * bring the item to view if it is not already visible.
+     *
+     * Note that any cell content rendered by a WidgetRenderer will not be
+     * visible in the editor row.
+     *
+     * @param itemId
+     *            the id of the item to edit
+     * @throws IllegalStateException
+     *             if the editor is not enabled or already editing an item in
+     *             buffered mode
+     * @throws IllegalArgumentException
+     *             if the {@code itemId} is not in the backing container
+     * @see #setEditorEnabled(boolean)
+     */
+    public void editItem(Object itemId)
+            throws IllegalStateException, IllegalArgumentException {
+        if (!isEditorEnabled()) {
+            throw new IllegalStateException("Item editor is not enabled");
+        } else if (isEditorBuffered() && editedItemId != null) {
+            throw new IllegalStateException("Editing item " + itemId
+                    + " failed. Item editor is already editing item "
+                    + editedItemId);
+        } else if (!getContainerDataSource().containsId(itemId)) {
+            throw new IllegalArgumentException("Item with id " + itemId
+                    + " not found in current container");
+        }
+        editedItemId = itemId;
+        getEditorRpc().bind(getContainerDataSource().indexOfId(itemId));
+    }
+
+    protected void doEditItem() {
+        Item item = getContainerDataSource().getItem(editedItemId);
+
+        editorFieldGroup.setItemDataSource(item);
+
+        for (Column column : getColumns()) {
+            column.getState().editorConnector = getEditorField(
+                    column.getPropertyId());
+        }
+
+        editorActive = true;
+        // Must ensure that all fields, recursively, are sent to the client
+        // This is needed because the fields are hidden using isRendered
+        for (LegacyField<?> f : getEditorFields()) {
+            f.markAsDirtyRecursive();
+        }
+
+        if (datasource instanceof ItemSetChangeNotifier) {
+            ((ItemSetChangeNotifier) datasource)
+                    .addItemSetChangeListener(editorClosingItemSetListener);
+        }
+    }
+
+    private void setEditorField(Object propertyId, LegacyField<?> field) {
+        checkColumnExists(propertyId);
+
+        LegacyField<?> oldField = editorFieldGroup.getField(propertyId);
+        if (oldField != null) {
+            editorFieldGroup.unbind(oldField);
+            oldField.setParent(null);
+        }
+
+        if (field != null) {
+            field.setParent(this);
+            editorFieldGroup.bind(field, propertyId);
+        }
+    }
+
+    /**
+     * Saves all changes done to the bound fields.
+     * <p>
+     * <em>Note:</em> This is a pass-through call to the backing field group.
+     *
+     * @throws CommitException
+     *             If the commit was aborted
+     *
+     * @see FieldGroup#commit()
+     */
+    public void saveEditor() throws CommitException {
+        editorFieldGroup.commit();
+    }
+
+    /**
+     * Cancels the currently active edit if any. Hides the editor and discards
+     * possible unsaved changes in the editor fields.
+     */
+    public void cancelEditor() {
+        if (isEditorActive()) {
+            getEditorRpc()
+                    .cancel(getContainerDataSource().indexOfId(editedItemId));
+            doCancelEditor();
+        }
+    }
+
+    protected void doCancelEditor() {
+        editedItemId = null;
+        editorActive = false;
+        editorFieldGroup.discard();
+        editorFieldGroup.setItemDataSource(null);
+
+        if (datasource instanceof ItemSetChangeNotifier) {
+            ((ItemSetChangeNotifier) datasource)
+                    .removeItemSetChangeListener(editorClosingItemSetListener);
+        }
+
+        // Mark Grid as dirty so the client side gets to know that the editors
+        // are no longer attached
+        markAsDirty();
+    }
+
+    void resetEditor() {
+        if (isEditorActive()) {
+            /*
+             * Simply force cancel the editing; throwing here would just make
+             * Grid.setContainerDataSource semantics more complicated.
+             */
+            cancelEditor();
+        }
+        for (LegacyField<?> editor : getEditorFields()) {
+            editor.setParent(null);
+        }
+
+        editedItemId = null;
+        editorActive = false;
+        editorFieldGroup = new CustomFieldGroup();
+    }
+
+    /**
+     * Gets a collection of all fields bound to the item editor of this grid.
+     * <p>
+     * When {@link #editItem(Object) editItem} is called, fields are
+     * automatically created and bound to any unbound properties.
+     *
+     * @return a collection of all the fields bound to the item editor
+     */
+    Collection<LegacyField<?>> getEditorFields() {
+        Collection<LegacyField<?>> fields = editorFieldGroup.getFields();
+        assert allAttached(fields);
+        return fields;
+    }
+
+    private boolean allAttached(Collection<? extends Component> components) {
+        for (Component component : components) {
+            if (component.getParent() != this) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Sets the field factory for the {@link FieldGroup}. The field factory is
+     * only used when {@link FieldGroup} creates a new field.
+     * <p>
+     * <em>Note:</em> This is a pass-through call to the backing field group.
+     *
+     * @param fieldFactory
+     *            The field factory to use
+     */
+    public void setEditorFieldFactory(FieldGroupFieldFactory fieldFactory) {
+        editorFieldGroup.setFieldFactory(fieldFactory);
+    }
+
+    /**
+     * Sets the error handler for the editor.
+     *
+     * The error handler is called whenever there is an exception in the editor.
+     *
+     * @param editorErrorHandler
+     *            The editor error handler to use
+     * @throws IllegalArgumentException
+     *             if the error handler is null
+     */
+    public void setEditorErrorHandler(EditorErrorHandler editorErrorHandler)
+            throws IllegalArgumentException {
+        if (editorErrorHandler == null) {
+            throw new IllegalArgumentException(
+                    "The error handler cannot be null");
+        }
+        this.editorErrorHandler = editorErrorHandler;
+    }
+
+    /**
+     * Gets the error handler used for the editor
+     *
+     * @see #setErrorHandler(com.vaadin.server.ErrorHandler)
+     * @return the editor error handler, never null
+     */
+    public EditorErrorHandler getEditorErrorHandler() {
+        return editorErrorHandler;
+    }
+
+    /**
+     * Gets the field factory for the {@link FieldGroup}. The field factory is
+     * only used when {@link FieldGroup} creates a new field.
+     * <p>
+     * <em>Note:</em> This is a pass-through call to the backing field group.
+     *
+     * @return The field factory in use
+     */
+    public FieldGroupFieldFactory getEditorFieldFactory() {
+        return editorFieldGroup.getFieldFactory();
+    }
+
+    /**
+     * Sets the caption on the save button in the Grid editor.
+     *
+     * @param saveCaption
+     *            the caption to set
+     * @throws IllegalArgumentException
+     *             if {@code saveCaption} is {@code null}
+     */
+    public void setEditorSaveCaption(String saveCaption)
+            throws IllegalArgumentException {
+        if (saveCaption == null) {
+            throw new IllegalArgumentException("Save caption cannot be null");
+        }
+        getState().editorSaveCaption = saveCaption;
+    }
+
+    /**
+     * Gets the current caption of the save button in the Grid editor.
+     *
+     * @return the current caption of the save button
+     */
+    public String getEditorSaveCaption() {
+        return getState(false).editorSaveCaption;
+    }
+
+    /**
+     * Sets the caption on the cancel button in the Grid editor.
+     *
+     * @param cancelCaption
+     *            the caption to set
+     * @throws IllegalArgumentException
+     *             if {@code cancelCaption} is {@code null}
+     */
+    public void setEditorCancelCaption(String cancelCaption)
+            throws IllegalArgumentException {
+        if (cancelCaption == null) {
+            throw new IllegalArgumentException("Cancel caption cannot be null");
+        }
+        getState().editorCancelCaption = cancelCaption;
+    }
+
+    /**
+     * Gets the current caption of the cancel button in the Grid editor.
+     *
+     * @return the current caption of the cancel button
+     */
+    public String getEditorCancelCaption() {
+        return getState(false).editorCancelCaption;
+    }
+
+    /**
+     * Sets the buffered editor mode. The default mode is buffered (
+     * <code>true</code>).
+     *
+     * @since 7.6
+     * @param editorBuffered
+     *            <code>true</code> to enable buffered editor,
+     *            <code>false</code> to disable it
+     * @throws IllegalStateException
+     *             If editor is active while attempting to change the buffered
+     *             mode.
+     */
+    public void setEditorBuffered(boolean editorBuffered)
+            throws IllegalStateException {
+        if (isEditorActive()) {
+            throw new IllegalStateException(
+                    "Can't change editor unbuffered mode while editor is active.");
+        }
+        getState().editorBuffered = editorBuffered;
+        editorFieldGroup.setBuffered(editorBuffered);
+    }
+
+    /**
+     * Gets the buffered editor mode.
+     *
+     * @since 7.6
+     * @return <code>true</code> if buffered editor is enabled,
+     *         <code>false</code> otherwise
+     */
+    public boolean isEditorBuffered() {
+        return getState(false).editorBuffered;
+    }
+
+    @Override
+    public void addItemClickListener(ItemClickListener listener) {
+        addListener(GridConstants.ITEM_CLICK_EVENT_ID, ItemClickEvent.class,
+                listener, ItemClickEvent.ITEM_CLICK_METHOD);
+    }
+
+    @Override
+    @Deprecated
+    public void addListener(ItemClickListener listener) {
+        addItemClickListener(listener);
+    }
+
+    @Override
+    public void removeItemClickListener(ItemClickListener listener) {
+        removeListener(GridConstants.ITEM_CLICK_EVENT_ID, ItemClickEvent.class,
+                listener);
+    }
+
+    @Override
+    @Deprecated
+    public void removeListener(ItemClickListener listener) {
+        removeItemClickListener(listener);
+    }
+
+    /**
+     * Requests that the column widths should be recalculated.
+     * <p>
+     * In most cases Grid will know when column widths need to be recalculated
+     * but this method can be used to force recalculation in situations when
+     * grid does not recalculate automatically.
+     *
+     * @since 7.4.1
+     */
+    public void recalculateColumnWidths() {
+        getRpcProxy(GridClientRpc.class).recalculateColumnWidths();
+    }
+
+    /**
+     * Registers a new column visibility change listener
+     *
+     * @since 7.5.0
+     * @param listener
+     *            the listener to register
+     */
+    public void addColumnVisibilityChangeListener(
+            ColumnVisibilityChangeListener listener) {
+        addListener(ColumnVisibilityChangeEvent.class, listener,
+                COLUMN_VISIBILITY_METHOD);
+    }
+
+    /**
+     * Removes a previously registered column visibility change listener
+     *
+     * @since 7.5.0
+     * @param listener
+     *            the listener to remove
+     */
+    public void removeColumnVisibilityChangeListener(
+            ColumnVisibilityChangeListener listener) {
+        removeListener(ColumnVisibilityChangeEvent.class, listener,
+                COLUMN_VISIBILITY_METHOD);
+    }
+
+    private void fireColumnVisibilityChangeEvent(Column column, boolean hidden,
+            boolean isUserOriginated) {
+        fireEvent(new ColumnVisibilityChangeEvent(this, column, hidden,
+                isUserOriginated));
+    }
+
+    /**
+     * Sets a new details generator for row details.
+     * <p>
+     * The currently opened row details will be re-rendered.
+     *
+     * @since 7.5.0
+     * @param detailsGenerator
+     *            the details generator to set
+     * @throws IllegalArgumentException
+     *             if detailsGenerator is <code>null</code>;
+     */
+    public void setDetailsGenerator(DetailsGenerator detailsGenerator)
+            throws IllegalArgumentException {
+        detailComponentManager.setDetailsGenerator(detailsGenerator);
+    }
+
+    /**
+     * Gets the current details generator for row details.
+     *
+     * @since 7.5.0
+     * @return the detailsGenerator the current details generator
+     */
+    public DetailsGenerator getDetailsGenerator() {
+        return detailComponentManager.getDetailsGenerator();
+    }
+
+    /**
+     * Shows or hides the details for a specific item.
+     *
+     * @since 7.5.0
+     * @param itemId
+     *            the id of the item for which to set details visibility
+     * @param visible
+     *            <code>true</code> to show the details, or <code>false</code>
+     *            to hide them
+     */
+    public void setDetailsVisible(Object itemId, boolean visible) {
+        detailComponentManager.setDetailsVisible(itemId, visible);
+    }
+
+    /**
+     * Checks whether details are visible for the given item.
+     *
+     * @since 7.5.0
+     * @param itemId
+     *            the id of the item for which to check details visibility
+     * @return <code>true</code> iff the details are visible
+     */
+    public boolean isDetailsVisible(Object itemId) {
+        return detailComponentManager.isDetailsVisible(itemId);
+    }
+
+    private static SelectionMode getDefaultSelectionMode() {
+        return SelectionMode.SINGLE;
+    }
+
+    @Override
+    public void readDesign(Element design, DesignContext context) {
+        super.readDesign(design, context);
+
+        Attributes attrs = design.attributes();
+        if (attrs.hasKey("editable")) {
+            setEditorEnabled(DesignAttributeHandler.readAttribute("editable",
+                    attrs, boolean.class));
+        }
+        if (attrs.hasKey("rows")) {
+            setHeightByRows(DesignAttributeHandler.readAttribute("rows", attrs,
+                    double.class));
+            setHeightMode(HeightMode.ROW);
+        }
+        if (attrs.hasKey("selection-mode")) {
+            setSelectionMode(DesignAttributeHandler.readAttribute(
+                    "selection-mode", attrs, SelectionMode.class));
+        }
+
+        if (design.children().size() > 0) {
+            if (design.children().size() > 1
+                    || !design.child(0).tagName().equals("table")) {
+                throw new DesignException(
+                        "Grid needs to have a table element as its only child");
+            }
+            Element table = design.child(0);
+
+            Elements colgroups = table.getElementsByTag("colgroup");
+            if (colgroups.size() != 1) {
+                throw new DesignException(
+                        "Table element in declarative Grid needs to have a"
+                                + " colgroup defining the columns used in Grid");
+            }
+
+            int i = 0;
+            for (Element col : colgroups.get(0).getElementsByTag("col")) {
+                String propertyId = DesignAttributeHandler.readAttribute(
+                        "property-id", col.attributes(), "property-" + i,
+                        String.class);
+                addColumn(propertyId, String.class).readDesign(col, context);
+                ++i;
+            }
+
+            for (Element child : table.children()) {
+                if (child.tagName().equals("thead")) {
+                    header.readDesign(child, context);
+                } else if (child.tagName().equals("tbody")) {
+                    for (Element row : child.children()) {
+                        Elements cells = row.children();
+                        Object[] data = new String[cells.size()];
+                        for (int c = 0; c < cells.size(); ++c) {
+                            data[c] = cells.get(c).html();
+                        }
+                        addRow(data);
+                    }
+
+                    // Since inline data is used, set HTML renderer for columns
+                    for (Column c : getColumns()) {
+                        c.setRenderer(new HtmlRenderer());
+                    }
+                } else if (child.tagName().equals("tfoot")) {
+                    footer.readDesign(child, context);
+                }
+            }
+        }
+
+        // Read frozen columns after columns are read.
+        if (attrs.hasKey("frozen-columns")) {
+            setFrozenColumnCount(DesignAttributeHandler
+                    .readAttribute("frozen-columns", attrs, int.class));
+        }
+    }
+
+    @Override
+    public void writeDesign(Element design, DesignContext context) {
+        super.writeDesign(design, context);
+
+        Attributes attrs = design.attributes();
+        LegacyGrid def = context.getDefaultInstance(this);
+
+        DesignAttributeHandler.writeAttribute("editable", attrs,
+                isEditorEnabled(), def.isEditorEnabled(), boolean.class);
+
+        DesignAttributeHandler.writeAttribute("frozen-columns", attrs,
+                getFrozenColumnCount(), def.getFrozenColumnCount(), int.class);
+
+        if (getHeightMode() == HeightMode.ROW) {
+            DesignAttributeHandler.writeAttribute("rows", attrs,
+                    getHeightByRows(), def.getHeightByRows(), double.class);
+        }
+
+        SelectionMode selectionMode = null;
+
+        if (selectionModel.getClass().equals(SingleSelectionModel.class)) {
+            selectionMode = SelectionMode.SINGLE;
+        } else if (selectionModel.getClass()
+                .equals(MultiSelectionModel.class)) {
+            selectionMode = SelectionMode.MULTI;
+        } else if (selectionModel.getClass().equals(NoSelectionModel.class)) {
+            selectionMode = SelectionMode.NONE;
+        }
+
+        assert selectionMode != null : "Unexpected selection model "
+                + selectionModel.getClass().getName();
+
+        DesignAttributeHandler.writeAttribute("selection-mode", attrs,
+                selectionMode, getDefaultSelectionMode(), SelectionMode.class);
+
+        if (columns.isEmpty()) {
+            // Empty grid. Structure not needed.
+            return;
+        }
+
+        // Do structure.
+        Element tableElement = design.appendElement("table");
+        Element colGroup = tableElement.appendElement("colgroup");
+
+        List<Column> columnOrder = getColumns();
+        for (int i = 0; i < columnOrder.size(); ++i) {
+            Column column = columnOrder.get(i);
+            Element colElement = colGroup.appendElement("col");
+            column.writeDesign(colElement, context);
+        }
+
+        // Always write thead. Reads correctly when there no header rows
+        header.writeDesign(tableElement.appendElement("thead"), context);
+
+        if (context.shouldWriteData(this)) {
+            Element bodyElement = tableElement.appendElement("tbody");
+            for (Object itemId : datasource.getItemIds()) {
+                Element tableRow = bodyElement.appendElement("tr");
+                for (Column c : getColumns()) {
+                    Object value = datasource.getItem(itemId)
+                            .getItemProperty(c.getPropertyId()).getValue();
+                    tableRow.appendElement("td")
+                            .append((value != null ? DesignFormatter
+                                    .encodeForTextNode(value.toString()) : ""));
+                }
+            }
+        }
+
+        if (footer.getRowCount() > 0) {
+            footer.writeDesign(tableElement.appendElement("tfoot"), context);
+        }
+    }
+
+    @Override
+    protected Collection<String> getCustomAttributes() {
+        Collection<String> result = super.getCustomAttributes();
+        result.add("editor-enabled");
+        result.add("editable");
+        result.add("frozen-column-count");
+        result.add("frozen-columns");
+        result.add("height-by-rows");
+        result.add("rows");
+        result.add("selection-mode");
+        result.add("header-visible");
+        result.add("footer-visible");
+        result.add("editor-error-handler");
+        result.add("height-mode");
+
+        return result;
+    }
+}