vaadin-framework/compatibility-client/src/main/java/com/vaadin/v7/client/connectors/GridConnector.java

/*
 * 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.v7.client.connectors;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.logging.Logger;

import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.EventTarget;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.client.ComponentConnector;
import com.vaadin.client.ConnectorHierarchyChangeEvent;
import com.vaadin.client.DeferredWorker;
import com.vaadin.client.MouseEventDetailsBuilder;
import com.vaadin.client.ServerConnector;
import com.vaadin.client.TooltipInfo;
import com.vaadin.client.WidgetUtil;
import com.vaadin.client.communication.StateChangeEvent;
import com.vaadin.client.communication.StateChangeEvent.StateChangeHandler;
import com.vaadin.client.ui.AbstractComponentConnector;
import com.vaadin.client.ui.AbstractHasComponentsConnector;
import com.vaadin.client.ui.ConnectorFocusAndBlurHandler;
import com.vaadin.client.ui.SimpleManagedLayout;
import com.vaadin.shared.MouseEventDetails;
import com.vaadin.shared.data.sort.SortDirection;
import com.vaadin.shared.ui.Connect;
import com.vaadin.v7.client.connectors.RpcDataSourceConnector.DetailsListener;
import com.vaadin.v7.client.connectors.RpcDataSourceConnector.RpcDataSource;
import com.vaadin.v7.client.widget.escalator.events.RowHeightChangedEvent;
import com.vaadin.v7.client.widget.escalator.events.RowHeightChangedHandler;
import com.vaadin.v7.client.widget.grid.CellReference;
import com.vaadin.v7.client.widget.grid.CellStyleGenerator;
import com.vaadin.v7.client.widget.grid.EditorHandler;
import com.vaadin.v7.client.widget.grid.EventCellReference;
import com.vaadin.v7.client.widget.grid.HeightAwareDetailsGenerator;
import com.vaadin.v7.client.widget.grid.RowReference;
import com.vaadin.v7.client.widget.grid.RowStyleGenerator;
import com.vaadin.v7.client.widget.grid.events.BodyClickHandler;
import com.vaadin.v7.client.widget.grid.events.BodyDoubleClickHandler;
import com.vaadin.v7.client.widget.grid.events.ColumnReorderEvent;
import com.vaadin.v7.client.widget.grid.events.ColumnReorderHandler;
import com.vaadin.v7.client.widget.grid.events.ColumnResizeEvent;
import com.vaadin.v7.client.widget.grid.events.ColumnResizeHandler;
import com.vaadin.v7.client.widget.grid.events.ColumnVisibilityChangeEvent;
import com.vaadin.v7.client.widget.grid.events.ColumnVisibilityChangeHandler;
import com.vaadin.v7.client.widget.grid.events.GridClickEvent;
import com.vaadin.v7.client.widget.grid.events.GridDoubleClickEvent;
import com.vaadin.v7.client.widget.grid.sort.SortEvent;
import com.vaadin.v7.client.widget.grid.sort.SortHandler;
import com.vaadin.v7.client.widget.grid.sort.SortOrder;
import com.vaadin.v7.client.widgets.Grid;
import com.vaadin.v7.client.widgets.Grid.Column;
import com.vaadin.v7.client.widgets.Grid.FooterCell;
import com.vaadin.v7.client.widgets.Grid.FooterRow;
import com.vaadin.v7.client.widgets.Grid.HeaderCell;
import com.vaadin.v7.client.widgets.Grid.HeaderRow;
import com.vaadin.v7.shared.ui.grid.EditorClientRpc;
import com.vaadin.v7.shared.ui.grid.EditorServerRpc;
import com.vaadin.v7.shared.ui.grid.GridClientRpc;
import com.vaadin.v7.shared.ui.grid.GridColumnState;
import com.vaadin.v7.shared.ui.grid.GridConstants;
import com.vaadin.v7.shared.ui.grid.GridConstants.Section;
import com.vaadin.v7.shared.ui.grid.GridServerRpc;
import com.vaadin.v7.shared.ui.grid.GridState;
import com.vaadin.v7.shared.ui.grid.GridStaticSectionState;
import com.vaadin.v7.shared.ui.grid.GridStaticSectionState.CellState;
import com.vaadin.v7.shared.ui.grid.GridStaticSectionState.RowState;
import com.vaadin.v7.shared.ui.grid.ScrollDestination;

import elemental.json.JsonObject;
import elemental.json.JsonValue;

/**
 * Connects the client side {@link Grid} widget with the server side
 * {@link com.vaadin.ui.components.grid.Grid} component.
 * <p>
 * The Grid is typed to JSONObject. The structure of the JSONObject is described
 * at {@link com.vaadin.shared.data.DataProviderRpc#setRowData(int, List)
 * DataProviderRpc.setRowData(int, List)}.
 *
 * @since 7.4
 * @author Vaadin Ltd
 */
@Connect(com.vaadin.v7.ui.Grid.class)
public class GridConnector extends AbstractHasComponentsConnector
        implements SimpleManagedLayout, DeferredWorker {

    private static final class CustomStyleGenerator implements
            CellStyleGenerator<JsonObject>, RowStyleGenerator<JsonObject> {
        @Override
        public String getStyle(CellReference<JsonObject> cellReference) {
            JsonObject row = cellReference.getRow();
            if (!row.hasKey(GridState.JSONKEY_CELLSTYLES)) {
                return null;
            }

            Column<?, JsonObject> column = cellReference.getColumn();
            if (!(column instanceof CustomGridColumn)) {
                // Selection checkbox column
                return null;
            }
            CustomGridColumn c = (CustomGridColumn) column;

            JsonObject cellStylesObject = row
                    .getObject(GridState.JSONKEY_CELLSTYLES);
            assert cellStylesObject != null;

            if (cellStylesObject.hasKey(c.id)) {
                return cellStylesObject.getString(c.id);
            } else {
                return null;
            }
        }

        @Override
        public String getStyle(RowReference<JsonObject> rowReference) {
            JsonObject row = rowReference.getRow();
            if (row.hasKey(GridState.JSONKEY_ROWSTYLE)) {
                return row.getString(GridState.JSONKEY_ROWSTYLE);
            } else {
                return null;
            }
        }
    }

    /**
     * Custom implementation of the custom grid column using a JSONObject to
     * represent the cell value and String as a column type.
     */
    private class CustomGridColumn extends Grid.Column<Object, JsonObject> {

        private final String id;

        private AbstractGridRendererConnector<Object> rendererConnector;

        private AbstractComponentConnector editorConnector;

        private HandlerRegistration errorStateHandler;

        public CustomGridColumn(String id,
                AbstractGridRendererConnector<Object> rendererConnector) {
            super(rendererConnector.getRenderer());
            this.rendererConnector = rendererConnector;
            this.id = id;
        }

        /**
         * Sets a new renderer for this column object
         *
         * @param rendererConnector
         *            a renderer connector object
         */
        public void setRenderer(
                AbstractGridRendererConnector<Object> rendererConnector) {
            setRenderer(rendererConnector.getRenderer());
            this.rendererConnector = rendererConnector;
        }

        @Override
        public Object getValue(final JsonObject obj) {
            final JsonObject rowData = obj.getObject(GridState.JSONKEY_DATA);

            if (rowData.hasKey(id)) {
                final JsonValue columnValue = rowData.get(id);

                return rendererConnector.decode(columnValue);
            }

            return null;
        }

        private AbstractComponentConnector getEditorConnector() {
            return editorConnector;
        }

        private void setEditorConnector(
                final AbstractComponentConnector editorConnector) {
            this.editorConnector = editorConnector;

            if (errorStateHandler != null) {
                errorStateHandler.removeHandler();
                errorStateHandler = null;
            }

            // Avoid nesting too deep
            if (editorConnector == null) {
                return;
            }

            errorStateHandler = editorConnector.addStateChangeHandler(
                    "errorMessage", new StateChangeHandler() {

                        @Override
                        public void onStateChanged(
                                StateChangeEvent stateChangeEvent) {

                            String error = editorConnector
                                    .getState().errorMessage;

                            if (error == null) {
                                columnToErrorMessage
                                        .remove(CustomGridColumn.this);
                            } else {
                                // The error message is formatted as HTML;
                                // therefore, we use this hack to make the
                                // string human-readable.
                                Element e = DOM.createElement("div");
                                e.setInnerHTML(editorConnector
                                        .getState().errorMessage);
                                error = getHeaderCaption() + ": "
                                        + e.getInnerText();

                                columnToErrorMessage.put(CustomGridColumn.this,
                                        error);
                            }

                            // Handle Editor RPC before updating error status
                            Scheduler.get()
                                    .scheduleFinally(new ScheduledCommand() {

                                        @Override
                                        public void execute() {
                                            updateErrorColumns();
                                        }
                                    });
                        }

                        public void updateErrorColumns() {
                            getWidget().getEditor().setEditorError(
                                    getColumnErrors(),
                                    columnToErrorMessage.keySet());
                        }
                    });
        }
    }

    /*
     * An editor handler using Vaadin RPC to manage the editor state.
     */
    private class CustomEditorHandler implements EditorHandler<JsonObject> {

        private EditorServerRpc rpc = getRpcProxy(EditorServerRpc.class);

        private EditorRequest<JsonObject> currentRequest = null;
        private boolean serverInitiated = false;

        public CustomEditorHandler() {
            registerRpc(EditorClientRpc.class, new EditorClientRpc() {

                @Override
                public void bind(final int rowIndex) {
                    // call this deferred to avoid issues with editing on init
                    Scheduler.get().scheduleDeferred(new ScheduledCommand() {
                        @Override
                        public void execute() {
                            GridConnector.this.getWidget().editRow(rowIndex);
                        }
                    });
                }

                @Override
                public void cancel(int rowIndex) {
                    serverInitiated = true;
                    GridConnector.this.getWidget().cancelEditor();
                }

                @Override
                public void confirmBind(final boolean bindSucceeded) {
                    endRequest(bindSucceeded, null, null);
                }

                @Override
                public void confirmSave(boolean saveSucceeded,
                        String errorMessage, List<String> errorColumnsIds) {
                    endRequest(saveSucceeded, errorMessage, errorColumnsIds);
                }
            });
        }

        @Override
        public void bind(EditorRequest<JsonObject> request) {
            startRequest(request);
            rpc.bind(request.getRowIndex());
        }

        @Override
        public void save(EditorRequest<JsonObject> request) {
            startRequest(request);
            rpc.save(request.getRowIndex());
        }

        @Override
        public void cancel(EditorRequest<JsonObject> request) {
            if (!handleServerInitiated(request)) {
                // No startRequest as we don't get (or need)
                // a confirmation from the server
                rpc.cancel(request.getRowIndex());
            }
        }

        @Override
        public Widget getWidget(Grid.Column<?, JsonObject> column) {
            assert column != null;

            if (column instanceof CustomGridColumn) {
                AbstractComponentConnector c = ((CustomGridColumn) column)
                        .getEditorConnector();

                if (c == null) {
                    return null;
                }

                return c.getWidget();
            } else {
                throw new IllegalStateException("Unexpected column type: "
                        + column.getClass().getName());
            }
        }

        /**
         * Used to handle the case where the editor calls us because it was
         * invoked by the server via RPC and not by the client. In that case,
         * the request can be simply synchronously completed.
         *
         * @param request
         *            the request object
         * @return true if the request was originally triggered by the server,
         *         false otherwise
         */
        private boolean handleServerInitiated(EditorRequest<?> request) {
            assert request != null : "Cannot handle null request";
            assert currentRequest == null : "Earlier request not yet finished";

            if (serverInitiated) {
                serverInitiated = false;
                request.success();
                return true;
            } else {
                return false;
            }
        }

        private void startRequest(EditorRequest<JsonObject> request) {
            assert currentRequest == null : "Earlier request not yet finished";

            currentRequest = request;
        }

        private void endRequest(boolean succeeded, String errorMessage,
                List<String> errorColumnsIds) {
            assert currentRequest != null : "Current request was null";
            /*
             * Clear current request first to ensure the state is valid if
             * another request is made in the callback.
             */
            EditorRequest<JsonObject> request = currentRequest;
            currentRequest = null;
            if (succeeded) {
                request.success();
            } else {
                Collection<Column<?, JsonObject>> errorColumns;
                if (errorColumnsIds != null) {
                    errorColumns = new ArrayList<>();
                    for (String colId : errorColumnsIds) {
                        errorColumns.add(columnIdToColumn.get(colId));
                    }
                } else {
                    errorColumns = null;
                }

                request.failure(errorMessage, errorColumns);
            }
        }
    }

    private class ItemClickHandler
            implements BodyClickHandler, BodyDoubleClickHandler {

        @Override
        public void onClick(GridClickEvent event) {
            if (hasEventListener(GridConstants.ITEM_CLICK_EVENT_ID)) {
                fireItemClick(event.getTargetCell(), event.getNativeEvent());
            }
        }

        @Override
        public void onDoubleClick(GridDoubleClickEvent event) {
            if (hasEventListener(GridConstants.ITEM_CLICK_EVENT_ID)) {
                fireItemClick(event.getTargetCell(), event.getNativeEvent());
            }
        }

        private void fireItemClick(CellReference<?> cell,
                NativeEvent mouseEvent) {
            String rowKey = getRowKey((JsonObject) cell.getRow());
            String columnId = getColumnId(cell.getColumn());
            getRpcProxy(GridServerRpc.class).itemClick(rowKey, columnId,
                    MouseEventDetailsBuilder
                            .buildMouseEventDetails(mouseEvent));
        }
    }

    private ColumnReorderHandler<JsonObject> columnReorderHandler = new ColumnReorderHandler<JsonObject>() {

        @Override
        public void onColumnReorder(ColumnReorderEvent<JsonObject> event) {
            if (!columnsUpdatedFromState) {
                List<Column<?, JsonObject>> columns = getWidget().getColumns();
                final List<String> newColumnOrder = new ArrayList<>();
                for (Column<?, JsonObject> column : columns) {
                    if (column instanceof CustomGridColumn) {
                        newColumnOrder.add(((CustomGridColumn) column).id);
                    } // the other case would be the multi selection column
                }
                getRpcProxy(GridServerRpc.class)
                        .columnsReordered(newColumnOrder, columnOrder);
                columnOrder = newColumnOrder;
                getState().columnOrder = newColumnOrder;
            }
        }
    };

    private ColumnVisibilityChangeHandler<JsonObject> columnVisibilityChangeHandler = new ColumnVisibilityChangeHandler<JsonObject>() {

        @Override
        public void onVisibilityChange(
                ColumnVisibilityChangeEvent<JsonObject> event) {
            if (!columnsUpdatedFromState) {
                Column<?, JsonObject> column = event.getColumn();
                if (column instanceof CustomGridColumn) {
                    getRpcProxy(GridServerRpc.class).columnVisibilityChanged(
                            ((CustomGridColumn) column).id, column.isHidden(),
                            event.isUserOriginated());
                    for (GridColumnState state : getState().columns) {
                        if (state.id.equals(((CustomGridColumn) column).id)) {
                            state.hidden = event.isHidden();
                            break;
                        }
                    }
                } else {
                    getLogger().warning(
                            "Visibility changed for a unknown column type in Grid: "
                                    + column.toString() + ", type "
                                    + column.getClass());
                }
            }
        }
    };

    private ColumnResizeHandler<JsonObject> columnResizeHandler = new ColumnResizeHandler<JsonObject>() {

        @Override
        public void onColumnResize(ColumnResizeEvent<JsonObject> event) {
            if (!columnsUpdatedFromState) {
                Column<?, JsonObject> column = event.getColumn();
                if (column instanceof CustomGridColumn) {
                    getRpcProxy(GridServerRpc.class).columnResized(
                            ((CustomGridColumn) column).id,
                            column.getWidthActual());
                }
            }
        }
    };

    private class CustomDetailsGenerator
            implements HeightAwareDetailsGenerator {

        private final Map<String, ComponentConnector> idToDetailsMap = new HashMap<>();
        private final Map<String, Integer> idToRowIndex = new HashMap<>();

        @Override
        public Widget getDetails(int rowIndex) {
            String id = getId(rowIndex);
            if (id == null) {
                return null;
            }
            ComponentConnector componentConnector = idToDetailsMap.get(id);
            idToRowIndex.put(id, rowIndex);

            return componentConnector.getWidget();
        }

        @Override
        public double getDetailsHeight(int rowIndex) {
            // Case of null is handled in the getDetails method and this method
            // will not called if it returns null.
            String id = getId(rowIndex);
            ComponentConnector componentConnector = idToDetailsMap.get(id);

            getLayoutManager().setNeedsMeasureRecursively(componentConnector);
            getLayoutManager().layoutNow();

            return getLayoutManager().getOuterHeightDouble(
                    componentConnector.getWidget().getElement());
        }

        /**
         * Fetches id from the row object that corresponds with the given
         * rowIndex.
         *
         * @since 7.6.1
         * @param rowIndex
         *            the index of the row for which to fetch the id
         * @return id of the row if such id exists, {@code null} otherwise
         */
        private String getId(int rowIndex) {
            JsonObject row = getWidget().getDataSource().getRow(rowIndex);

            if (!row.hasKey(GridState.JSONKEY_DETAILS_VISIBLE) || row
                    .getString(GridState.JSONKEY_DETAILS_VISIBLE).isEmpty()) {
                return null;
            }

            return row.getString(GridState.JSONKEY_DETAILS_VISIBLE);
        }

        public void updateConnectorHierarchy(List<ServerConnector> children) {
            Set<String> connectorIds = new HashSet<>();
            for (ServerConnector child : children) {
                if (child instanceof ComponentConnector) {
                    connectorIds.add(child.getConnectorId());
                    idToDetailsMap.put(child.getConnectorId(),
                            (ComponentConnector) child);
                }
            }

            Set<String> removedDetails = new HashSet<>();
            for (Entry<String, ComponentConnector> entry : idToDetailsMap
                    .entrySet()) {
                ComponentConnector connector = entry.getValue();
                String id = connector.getConnectorId();
                if (!connectorIds.contains(id)) {
                    removedDetails.add(entry.getKey());
                    if (idToRowIndex.containsKey(id)) {
                        getWidget().setDetailsVisible(idToRowIndex.get(id),
                                false);
                    }
                }
            }

            for (String id : removedDetails) {
                idToDetailsMap.remove(id);
                idToRowIndex.remove(id);
            }
        }
    }

    /**
     * Class for handling scrolling issues with open details.
     *
     * @since 7.5.2
     */
    private class LazyDetailsScroller implements DeferredWorker {

        /* Timer value tested to work in our test cluster with slow IE8s. */
        private static final int DISABLE_LAZY_SCROLL_TIMEOUT = 1500;

        /*
         * Cancels details opening scroll after timeout. Avoids any unexpected
         * scrolls via details opening.
         */
        private Timer disableScroller = new Timer() {
            @Override
            public void run() {
                targetRow = -1;
            }
        };

        private Integer targetRow = -1;
        private ScrollDestination destination = null;

        public void scrollToRow(Integer row, ScrollDestination dest) {
            targetRow = row;
            destination = dest;
            disableScroller.schedule(DISABLE_LAZY_SCROLL_TIMEOUT);
        }

        /**
         * Inform LazyDetailsScroller that a details row has opened on a row.
         *
         * @param rowIndex
         *            index of row with details now open
         */
        public void detailsOpened(int rowIndex) {
            if (targetRow == rowIndex) {
                getWidget().scrollToRow(targetRow, destination);
                disableScroller.run();
            }
        }

        @Override
        public boolean isWorkPending() {
            return disableScroller.isRunning();
        }
    }

    /**
     * Maps a generated column id to a grid column instance
     */
    private Map<String, CustomGridColumn> columnIdToColumn = new HashMap<>();

    private List<String> columnOrder = new ArrayList<>();

    /**
     * {@link #columnsUpdatedFromState} is set to true when
     * {@link #updateColumnOrderFromState(List)} is updating the column order
     * for the widget. This flag tells the {@link #columnReorderHandler} to not
     * send same data straight back to server. After updates, listener sets the
     * value back to false.
     */
    private boolean columnsUpdatedFromState;

    private RpcDataSource dataSource;

    /* Used to track Grid editor columns with validation errors */
    private final Map<Column<?, JsonObject>, String> columnToErrorMessage = new HashMap<>();

    private ItemClickHandler itemClickHandler = new ItemClickHandler();

    private String lastKnownTheme = null;

    private final CustomDetailsGenerator customDetailsGenerator = new CustomDetailsGenerator();
    private final CustomStyleGenerator styleGenerator = new CustomStyleGenerator();

    private final DetailsListener detailsListener = new DetailsListener() {
        @Override
        public void reapplyDetailsVisibility(final int rowIndex,
                final JsonObject row) {

            if (hasDetailsOpen(row)) {
                // Command for opening details row.
                ScheduledCommand openDetails = new ScheduledCommand() {
                    @Override
                    public void execute() {
                        // Re-apply to force redraw.
                        getWidget().setDetailsVisible(rowIndex, false);
                        getWidget().setDetailsVisible(rowIndex, true);
                        lazyDetailsScroller.detailsOpened(rowIndex);
                    }
                };

                if (initialChange) {
                    Scheduler.get().scheduleDeferred(openDetails);
                } else {
                    Scheduler.get().scheduleFinally(openDetails);
                }
            } else {
                getWidget().setDetailsVisible(rowIndex, false);
            }
        }

        private boolean hasDetailsOpen(JsonObject row) {
            return row.hasKey(GridState.JSONKEY_DETAILS_VISIBLE)
                    && row.getString(GridState.JSONKEY_DETAILS_VISIBLE) != null;
        }
    };

    private final LazyDetailsScroller lazyDetailsScroller = new LazyDetailsScroller();
    private final CustomEditorHandler editorHandler = new CustomEditorHandler();

    /*
     * Initially details need to behave a bit differently to allow some
     * escalator magic.
     */
    private boolean initialChange;

    @Override
    @SuppressWarnings("unchecked")
    public Grid<JsonObject> getWidget() {
        return (Grid<JsonObject>) super.getWidget();
    }

    @Override
    public GridState getState() {
        return (GridState) super.getState();
    }

    @Override
    protected void init() {
        super.init();

        // All scroll RPC calls are executed finally to avoid issues on init
        registerRpc(GridClientRpc.class, new GridClientRpc() {
            @Override
            public void scrollToStart() {
                /*
                 * no need for lazyDetailsScrollAdjuster, because the start is
                 * always 0, won't change a bit.
                 */
                Scheduler.get().scheduleFinally(new ScheduledCommand() {
                    @Override
                    public void execute() {
                        getWidget().scrollToStart();
                    }
                });
            }

            @Override
            public void scrollToEnd() {
                Scheduler.get().scheduleFinally(new ScheduledCommand() {
                    @Override
                    public void execute() {
                        getWidget().scrollToEnd();
                        // Scrolls further if details opens.
                        lazyDetailsScroller.scrollToRow(dataSource.size() - 1,
                                ScrollDestination.END);
                    }
                });
            }

            @Override
            public void scrollToRow(final int row,
                    final ScrollDestination destination) {
                Scheduler.get().scheduleFinally(new ScheduledCommand() {
                    @Override
                    public void execute() {
                        getWidget().scrollToRow(row, destination);
                        // Scrolls a bit further if details opens.
                        lazyDetailsScroller.scrollToRow(row, destination);
                    }
                });
            }

            @Override
            public void recalculateColumnWidths() {
                getWidget().recalculateColumnWidths();
            }
        });

        /* Item click events */
        getWidget().addBodyClickHandler(itemClickHandler);
        getWidget().addBodyDoubleClickHandler(itemClickHandler);

        /* Style Generators */
        getWidget().setCellStyleGenerator(styleGenerator);
        getWidget().setRowStyleGenerator(styleGenerator);

        getWidget().addSortHandler(new SortHandler<JsonObject>() {
            @Override
            public void sort(SortEvent<JsonObject> event) {
                List<SortOrder> order = event.getOrder();
                String[] columnIds = new String[order.size()];
                SortDirection[] directions = new SortDirection[order.size()];
                for (int i = 0; i < order.size(); i++) {
                    SortOrder sortOrder = order.get(i);
                    CustomGridColumn column = (CustomGridColumn) sortOrder
                            .getColumn();
                    columnIds[i] = column.id;

                    directions[i] = sortOrder.getDirection();
                }

                if (!Arrays.equals(columnIds, getState().sortColumns)
                        || !Arrays.equals(directions, getState().sortDirs)) {
                    // Report back to server if changed
                    getRpcProxy(GridServerRpc.class).sort(columnIds, directions,
                            event.isUserOriginated());
                }
            }
        });

        getWidget().setEditorHandler(editorHandler);
        getWidget().addColumnReorderHandler(columnReorderHandler);
        getWidget().addColumnVisibilityChangeHandler(
                columnVisibilityChangeHandler);
        getWidget().addColumnResizeHandler(columnResizeHandler);

        ConnectorFocusAndBlurHandler.addHandlers(this);

        getWidget().setDetailsGenerator(customDetailsGenerator);
        getLayoutManager().registerDependency(this, getWidget().getElement());

        // Handling row height changes
        getWidget().addRowHeightChangedHandler(new RowHeightChangedHandler() {
            @Override
            public void onRowHeightChanged(RowHeightChangedEvent event) {
                getLayoutManager()
                        .setNeedsMeasureRecursively(GridConnector.this);
                getLayoutManager().layoutNow();
            }
        });

        layout();
    }

    @Override
    public void onStateChanged(final StateChangeEvent stateChangeEvent) {
        super.onStateChanged(stateChangeEvent);

        initialChange = stateChangeEvent.isInitialStateChange();

        // Column updates
        if (stateChangeEvent.hasPropertyChanged("columns")) {

            // Remove old columns
            purgeRemovedColumns();

            // Add new columns
            for (GridColumnState state : getState().columns) {
                if (!columnIdToColumn.containsKey(state.id)) {
                    addColumnFromStateChangeEvent(state);
                }
                updateColumnFromStateChangeEvent(state);
            }
        }

        if (stateChangeEvent.hasPropertyChanged("columnOrder")) {
            if (orderNeedsUpdate(getState().columnOrder)) {
                updateColumnOrderFromState(getState().columnOrder);
            }
        }

        // Column resize mode
        if (stateChangeEvent.hasPropertyChanged("columnResizeMode")) {
            getWidget().setColumnResizeMode(getState().columnResizeMode);
        }

        // Header and footer
        if (stateChangeEvent.hasPropertyChanged("header")) {
            updateHeaderFromState(getState().header);
        }

        if (stateChangeEvent.hasPropertyChanged("footer")) {
            updateFooterFromState(getState().footer);
        }

        // Sorting
        if (stateChangeEvent.hasPropertyChanged("sortColumns")
                || stateChangeEvent.hasPropertyChanged("sortDirs")) {
            onSortStateChange();
        }

        // Editor
        if (stateChangeEvent.hasPropertyChanged("editorEnabled")) {
            getWidget().setEditorEnabled(getState().editorEnabled);
        }

        // Frozen columns
        if (stateChangeEvent.hasPropertyChanged("frozenColumnCount")) {
            getWidget().setFrozenColumnCount(getState().frozenColumnCount);
        }

        // Theme features
        String activeTheme = getConnection().getUIConnector().getActiveTheme();
        if (lastKnownTheme == null) {
            lastKnownTheme = activeTheme;
        } else if (!lastKnownTheme.equals(activeTheme)) {
            getWidget().resetSizesFromDom();
            lastKnownTheme = activeTheme;
        }
    }

    private void updateColumnOrderFromState(List<String> stateColumnOrder) {
        CustomGridColumn[] columns = new CustomGridColumn[stateColumnOrder
                .size()];
        int i = 0;
        for (String id : stateColumnOrder) {
            columns[i] = columnIdToColumn.get(id);
            i++;
        }
        columnsUpdatedFromState = true;
        getWidget().setColumnOrder(columns);
        columnsUpdatedFromState = false;
        columnOrder = stateColumnOrder;
    }

    private boolean orderNeedsUpdate(List<String> stateColumnOrder) {
        if (stateColumnOrder.size() == columnOrder.size()) {
            for (int i = 0; i < columnOrder.size(); ++i) {
                if (!stateColumnOrder.get(i).equals(columnOrder.get(i))) {
                    return true;
                }
            }
            return false;
        }
        return true;
    }

    private void updateHeaderFromState(GridStaticSectionState state) {
        getWidget().setHeaderVisible(state.visible);

        while (getWidget().getHeaderRowCount() > 0) {
            getWidget().removeHeaderRow(0);
        }

        for (RowState rowState : state.rows) {
            HeaderRow row = getWidget().appendHeaderRow();

            if (rowState.defaultRow) {
                getWidget().setDefaultHeaderRow(row);
            }

            for (CellState cellState : rowState.cells) {
                CustomGridColumn column = columnIdToColumn
                        .get(cellState.columnId);
                updateHeaderCellFromState(row.getCell(column), cellState);
            }

            for (Set<String> group : rowState.cellGroups.keySet()) {
                Grid.Column<?, ?>[] columns = new Grid.Column<?, ?>[group
                        .size()];
                CellState cellState = rowState.cellGroups.get(group);

                int i = 0;
                for (String columnId : group) {
                    columns[i] = columnIdToColumn.get(columnId);
                    i++;
                }

                // Set state to be the same as first in group.
                updateHeaderCellFromState(row.join(columns), cellState);
            }

            row.setStyleName(rowState.styleName);
        }
    }

    private void updateHeaderCellFromState(HeaderCell cell,
            CellState cellState) {
        switch (cellState.type) {
        case TEXT:
            cell.setText(cellState.text);
            break;
        case HTML:
            cell.setHtml(cellState.html);
            break;
        case WIDGET:
            ComponentConnector connector = (ComponentConnector) cellState.connector;
            if (connector != null) {
                cell.setWidget(connector.getWidget());
            } else {
                // This happens if you do setVisible(false) on the component on
                // the server side
                cell.setWidget(null);
            }
            break;
        default:
            throw new IllegalStateException(
                    "unexpected cell type: " + cellState.type);
        }
        cell.setStyleName(cellState.styleName);
    }

    private void updateFooterFromState(GridStaticSectionState state) {
        getWidget().setFooterVisible(state.visible);

        while (getWidget().getFooterRowCount() > 0) {
            getWidget().removeFooterRow(0);
        }

        for (RowState rowState : state.rows) {
            FooterRow row = getWidget().appendFooterRow();

            for (CellState cellState : rowState.cells) {
                CustomGridColumn column = columnIdToColumn
                        .get(cellState.columnId);
                updateFooterCellFromState(row.getCell(column), cellState);
            }

            for (Set<String> group : rowState.cellGroups.keySet()) {
                Grid.Column<?, ?>[] columns = new Grid.Column<?, ?>[group
                        .size()];
                CellState cellState = rowState.cellGroups.get(group);

                int i = 0;
                for (String columnId : group) {
                    columns[i] = columnIdToColumn.get(columnId);
                    i++;
                }

                // Set state to be the same as first in group.
                updateFooterCellFromState(row.join(columns), cellState);
            }

            row.setStyleName(rowState.styleName);
        }
    }

    private void updateFooterCellFromState(FooterCell cell,
            CellState cellState) {
        switch (cellState.type) {
        case TEXT:
            cell.setText(cellState.text);
            break;
        case HTML:
            cell.setHtml(cellState.html);
            break;
        case WIDGET:
            ComponentConnector connector = (ComponentConnector) cellState.connector;
            if (connector != null) {
                cell.setWidget(connector.getWidget());
            } else {
                // This happens if you do setVisible(false) on the component on
                // the server side
                cell.setWidget(null);
            }
            break;
        default:
            throw new IllegalStateException(
                    "unexpected cell type: " + cellState.type);
        }
        cell.setStyleName(cellState.styleName);
    }

    /**
     * Updates a column from a state change event.
     *
     * @param columnIndex
     *            The index of the column to update
     */
    private void updateColumnFromStateChangeEvent(GridColumnState columnState) {
        CustomGridColumn column = columnIdToColumn.get(columnState.id);

        columnsUpdatedFromState = true;
        updateColumnFromState(column, columnState);
        columnsUpdatedFromState = false;
    }

    /**
     * Adds a new column to the grid widget from a state change event
     *
     * @param columnIndex
     *            The index of the column, according to how it
     */
    private void addColumnFromStateChangeEvent(GridColumnState state) {
        @SuppressWarnings("unchecked")
        CustomGridColumn column = new CustomGridColumn(state.id,
                ((AbstractGridRendererConnector<Object>) state.rendererConnector));
        columnIdToColumn.put(state.id, column);

        /*
         * Add column to grid. Reordering is handled as a separate problem.
         */
        getWidget().addColumn(column);
        columnOrder.add(state.id);
    }

    /**
     * Updates the column values from a state
     *
     * @param column
     *            The column to update
     * @param state
     *            The state to get the data from
     */
    @SuppressWarnings("unchecked")
    private static void updateColumnFromState(CustomGridColumn column,
            GridColumnState state) {
        column.setWidth(state.width);
        column.setMinimumWidth(state.minWidth);
        column.setMaximumWidth(state.maxWidth);
        column.setExpandRatio(state.expandRatio);

        assert state.rendererConnector instanceof AbstractGridRendererConnector : "GridColumnState.rendererConnector is invalid (not subclass of AbstractGridRendererConnector)";
        column.setRenderer(
                (AbstractGridRendererConnector<Object>) state.rendererConnector);

        column.setSortable(state.sortable);

        column.setResizable(state.resizable);

        column.setHeaderCaption(state.headerCaption);

        column.setHidden(state.hidden);
        column.setHidable(state.hidable);
        column.setHidingToggleCaption(state.hidingToggleCaption);

        column.setEditable(state.editable);
        column.setEditorConnector(
                (AbstractComponentConnector) state.editorConnector);
    }

    /**
     * Removes any orphan columns that has been removed from the state from the
     * grid
     */
    private void purgeRemovedColumns() {

        // Get columns still registered in the state
        Set<String> columnsInState = new HashSet<>();
        for (GridColumnState columnState : getState().columns) {
            columnsInState.add(columnState.id);
        }

        // Remove column no longer in state
        Iterator<String> columnIdIterator = columnIdToColumn.keySet()
                .iterator();
        while (columnIdIterator.hasNext()) {
            String id = columnIdIterator.next();
            if (!columnsInState.contains(id)) {
                CustomGridColumn column = columnIdToColumn.get(id);
                columnIdIterator.remove();
                getWidget().removeColumn(column);
                columnOrder.remove(id);
            }
        }
    }

    public void setDataSource(RpcDataSource dataSource) {
        this.dataSource = dataSource;
        getWidget().setDataSource(this.dataSource);
    }

    private void onSortStateChange() {
        List<SortOrder> sortOrder = new ArrayList<>();

        String[] sortColumns = getState().sortColumns;
        SortDirection[] sortDirs = getState().sortDirs;

        for (int i = 0; i < sortColumns.length; i++) {
            sortOrder.add(new SortOrder(columnIdToColumn.get(sortColumns[i]),
                    sortDirs[i]));
        }

        getWidget().setSortOrder(sortOrder);
    }

    private Logger getLogger() {
        return Logger.getLogger(getClass().getName());
    }

    /**
     * Gets the row key for a row object.
     *
     * @param row
     *            the row object
     * @return the key for the given row
     */
    public String getRowKey(JsonObject row) {
        final Object key = dataSource.getRowKey(row);
        assert key instanceof String : "Internal key was not a String but a "
                + key.getClass().getSimpleName() + " (" + key + ")";
        return (String) key;
    }

    /*
     * (non-Javadoc)
     *
     * @see
     * com.vaadin.client.HasComponentsConnector#updateCaption(com.vaadin.client
     * .ComponentConnector)
     */
    @Override
    public void updateCaption(ComponentConnector connector) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onConnectorHierarchyChange(
            ConnectorHierarchyChangeEvent connectorHierarchyChangeEvent) {
        customDetailsGenerator.updateConnectorHierarchy(getChildren());
    }

    public String getColumnId(Grid.Column<?, ?> column) {
        if (column instanceof CustomGridColumn) {
            return ((CustomGridColumn) column).id;
        }
        return null;
    }

    @Override
    public void layout() {
        getWidget().onResize();
    }

    @Override
    public boolean isWorkPending() {
        return lazyDetailsScroller.isWorkPending();
    }

    /**
     * Gets the listener used by this connector for tracking when row detail
     * visibility changes.
     *
     * @since 7.5.0
     * @return the used details listener
     */
    public DetailsListener getDetailsListener() {
        return detailsListener;
    }

    @Override
    public boolean hasTooltip() {
        return getState().hasDescriptions || super.hasTooltip();
    }

    @Override
    public TooltipInfo getTooltipInfo(Element element) {
        CellReference<JsonObject> cell = getWidget().getCellReference(element);

        if (cell != null) {
            JsonObject row = cell.getRow();
            if (row == null) {
                return null;
            }

            Column<?, JsonObject> column = cell.getColumn();
            if (!(column instanceof CustomGridColumn)) {
                // Selection checkbox column
                return null;
            }
            CustomGridColumn c = (CustomGridColumn) column;

            JsonObject cellDescriptions = row
                    .getObject(GridState.JSONKEY_CELLDESCRIPTION);

            if (cellDescriptions != null && cellDescriptions.hasKey(c.id)) {
                return new TooltipInfo(cellDescriptions.getString(c.id));
            } else if (row.hasKey(GridState.JSONKEY_ROWDESCRIPTION)) {
                return new TooltipInfo(
                        row.getString(GridState.JSONKEY_ROWDESCRIPTION));
            } else {
                return null;
            }
        }

        return super.getTooltipInfo(element);
    }

    @Override
    protected void sendContextClickEvent(MouseEventDetails details,
            EventTarget eventTarget) {
        // if element is the resize indicator, ignore the event
        if (isResizeHandle(eventTarget)) {
            WidgetUtil.clearTextSelection();
            return;
        }

        EventCellReference<JsonObject> eventCell = getWidget().getEventCell();

        Section section = eventCell.getSection();
        String rowKey = null;
        if (eventCell.isBody() && eventCell.getRow() != null) {
            rowKey = getRowKey(eventCell.getRow());
        }

        String columnId = getColumnId(eventCell.getColumn());

        getRpcProxy(GridServerRpc.class).contextClick(eventCell.getRowIndex(),
                rowKey, columnId, section, details);

        WidgetUtil.clearTextSelection();
    }

    private boolean isResizeHandle(EventTarget eventTarget) {
        if (Element.is(eventTarget)) {
            Element e = Element.as(eventTarget);
            if (e.getClassName().contains("-column-resize-handle")) {
                return true;
            }
        }
        return false;
    }

    /**
     * Creates a concatenation of all columns errors for Editor.
     *
     * @since 7.6
     * @return displayed error string
     */
    private String getColumnErrors() {
        List<String> errors = new ArrayList<>();

        for (Grid.Column<?, JsonObject> c : getWidget().getColumns()) {
            if (!(c instanceof CustomGridColumn)) {
                continue;
            }

            String error = columnToErrorMessage.get(c);
            if (error != null) {
                errors.add(error);
            }
        }

        String result = "";
        Iterator<String> i = errors.iterator();
        while (i.hasNext()) {
            result += i.next();
            if (i.hasNext()) {
                result += ", ";
            }
        }
        return result.isEmpty() ? null : result;
    }

}