Grid supports data set changes (#12645)

Change-Id: I5ceb52dea079f48b0065c1b2dbdc35b30fe8c4ee

2 files changed, 420 insertions, 13 deletions

diff --git a/server/src/com/vaadin/data/RpcDataProviderExtension.java b/server/src/com/vaadin/data/RpcDataProviderExtension.java
index 48f03b98c0..b22e6a209b 100644
--- a/server/src/com/vaadin/data/RpcDataProviderExtension.java
+++ b/server/src/com/vaadin/data/RpcDataProviderExtension.java
@@ -18,6 +18,7 @@ package com.vaadin.data;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 
 import com.vaadin.data.Container.Indexed;
@@ -67,22 +68,24 @@ public class RpcDataProviderExtension extends AbstractExtension {
         Collection<?> propertyIds = container.getContainerPropertyIds();
         List<String[]> rows = new ArrayList<String[]>(itemIds.size());
         for (Object itemId : itemIds) {
-            Item item = container.getItem(itemId);
-            String[] row = new String[propertyIds.size()];
-
-            int i = 0;
-            for (Object propertyId : propertyIds) {
-                Object value = item.getItemProperty(propertyId).getValue();
-                String stringValue = String.valueOf(value);
-                row[i++] = stringValue;
-            }
-
-            rows.add(row);
+            rows.add(getRowData(propertyIds, itemId));
         }
-
         getRpcProxy(DataProviderRpc.class).setRowData(firstRow, rows);
     }
 
+    private String[] getRowData(Collection<?> propertyIds, Object itemId) {
+        Item item = container.getItem(itemId);
+        String[] row = new String[propertyIds.size()];
+
+        int i = 0;
+        for (Object propertyId : propertyIds) {
+            Object value = item.getItemProperty(propertyId).getValue();
+            String stringValue = String.valueOf(value);
+            row[i++] = stringValue;
+        }
+        return row;
+    }
+
     @Override
     protected DataProviderState getState() {
         return (DataProviderState) super.getState();
@@ -98,4 +101,48 @@ public class RpcDataProviderExtension extends AbstractExtension {
         super.extend(component);
     }
 
+    /**
+     * Informs the client side that new rows have been inserted into the data
+     * source.
+     * 
+     * @param index
+     *            the index at which new rows have been inserted
+     * @param count
+     *            the number of rows inserted at <code>index</code>
+     */
+    public void insertRowData(int index, int count) {
+        getState().containerSize += count;
+        getRpcProxy(DataProviderRpc.class).insertRowData(index, count);
+    }
+
+    /**
+     * Informs the client side that rows have been removed from the data source.
+     * 
+     * @param firstIndex
+     *            the index of the first row removed
+     * @param count
+     *            the number of rows removed
+     */
+    public void removeRowData(int firstIndex, int count) {
+        getState().containerSize -= count;
+        getRpcProxy(DataProviderRpc.class).removeRowData(firstIndex, count);
+    }
+
+    /**
+     * Informs the client side that data of a row has been modified in the data
+     * source.
+     * 
+     * @param index
+     *            the index of the row that was updated
+     */
+    public void updateRowData(int index) {
+        /*
+         * TODO: ignore duplicate requests for the same index during the same
+         * roundtrip.
+         */
+        Object itemId = container.getIdByIndex(index);
+        String[] row = getRowData(container.getContainerPropertyIds(), itemId);
+        getRpcProxy(DataProviderRpc.class).setRowData(index,
+                Collections.singletonList(row));
+    }
 }
diff --git a/server/src/com/vaadin/ui/components/grid/Grid.java b/server/src/com/vaadin/ui/components/grid/Grid.java
index 1fb0692104..08685874c1 100644
--- a/server/src/com/vaadin/ui/components/grid/Grid.java
+++ b/server/src/com/vaadin/ui/components/grid/Grid.java
@@ -26,15 +26,28 @@ import java.util.List;
 import java.util.Map;
 
 import com.vaadin.data.Container;
+import com.vaadin.data.Container.Indexed.ItemAddEvent;
+import com.vaadin.data.Container.Indexed.ItemRemoveEvent;
+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.Item;
+import com.vaadin.data.Property;
+import com.vaadin.data.Property.ValueChangeEvent;
+import com.vaadin.data.Property.ValueChangeListener;
+import com.vaadin.data.Property.ValueChangeNotifier;
 import com.vaadin.data.RpcDataProviderExtension;
 import com.vaadin.server.KeyMapper;
 import com.vaadin.shared.ui.grid.ColumnGroupRowState;
 import com.vaadin.shared.ui.grid.GridColumnState;
+import com.vaadin.shared.ui.grid.GridServerRpc;
 import com.vaadin.shared.ui.grid.GridState;
+import com.vaadin.shared.ui.grid.Range;
 import com.vaadin.ui.AbstractComponent;
+import com.vaadin.ui.Component;
 
 /**
  * Data grid component
@@ -57,6 +70,282 @@ import com.vaadin.ui.AbstractComponent;
 public class Grid extends AbstractComponent {
 
     /**
+     * A helper class that handles the client-side Escalator logic relating to
+     * making sure that whatever is currently visible to the user, is properly
+     * initialized and otherwise handled on the server side (as far as
+     * requried).
+     * <p>
+     * This bookeeping includes, but is not limited to:
+     * <ul>
+     * <li>listening to the currently visible {@link Property Properties'} value
+     * changes on the server side and sending those back to the client; and
+     * <li>attaching and detaching {@link Component Components} from the Vaadin
+     * Component hierarchy.
+     * </ul>
+     */
+    private final class ActiveRowHandler {
+        /**
+         * A map from itemId to the value change listener used for all of its
+         * properties
+         */
+        private final Map<Object, GridValueChangeListener> valueChangeListeners = new HashMap<Object, GridValueChangeListener>();
+
+        /**
+         * The currently active range. Practically, it's the range of row
+         * indices being displayed currently.
+         */
+        private Range activeRange = Range.withLength(0, 0);
+
+        /**
+         * A hook for making sure that appropriate data is "active". All other
+         * rows should be "inactive".
+         * <p>
+         * "Active" can mean different things in different contexts. For
+         * example, only the Properties in the active range need
+         * ValueChangeListeners. Also, whenever a row with a Component becomes
+         * active, it needs to be attached (and conversely, when inactive, it
+         * needs to be detached).
+         * 
+         * @param firstActiveRow
+         *            the first active row
+         * @param activeRowCount
+         *            the number of active rows
+         */
+        public void setActiveRows(int firstActiveRow, int activeRowCount) {
+
+            final Range newActiveRange = Range.withLength(firstActiveRow,
+                    activeRowCount);
+
+            // TODO [[Components]] attach and detach components
+
+            /*-
+             *  Example
+             * 
+             *  New Range:       [3, 4, 5, 6, 7]
+             *  Old Range: [1, 2, 3, 4, 5]
+             *  Result:    [1, 2][3, 4, 5]      []
+             */
+            final Range[] depractionPartition = activeRange
+                    .partitionWith(newActiveRange);
+            removeValueChangeListeners(depractionPartition[0]);
+            removeValueChangeListeners(depractionPartition[2]);
+
+            /*-
+             *  Example
+             *  
+             *  Old Range: [1, 2, 3, 4, 5]
+             *  New Range:       [3, 4, 5, 6, 7]
+             *  Result:    []    [3, 4, 5][6, 7]
+             */
+            final Range[] activationPartition = newActiveRange
+                    .partitionWith(activeRange);
+            addValueChangeListeners(activationPartition[0]);
+            addValueChangeListeners(activationPartition[2]);
+
+            activeRange = newActiveRange;
+        }
+
+        private void addValueChangeListeners(Range range) {
+            for (int i = range.getStart(); i < range.getEnd(); i++) {
+
+                final Object itemId = datasource.getIdByIndex(i);
+                final Item item = datasource.getItem(itemId);
+
+                if (valueChangeListeners.containsKey(itemId)) {
+                    /*
+                     * This might occur when items are removed from above the
+                     * viewport, the escalator scrolls up to compensate, but the
+                     * same items remain in the view: It looks as if one row was
+                     * scrolled, when in fact the whole viewport was shifted up.
+                     */
+                    continue;
+                }
+
+                GridValueChangeListener listener = new GridValueChangeListener(
+                        itemId);
+                valueChangeListeners.put(itemId, listener);
+
+                for (final Object propertyId : item.getItemPropertyIds()) {
+                    final Property<?> property = item
+                            .getItemProperty(propertyId);
+                    if (property instanceof ValueChangeNotifier) {
+                        ((ValueChangeNotifier) property)
+                                .addValueChangeListener(listener);
+                    }
+                }
+            }
+        }
+
+        private void removeValueChangeListeners(Range range) {
+            for (int i = range.getStart(); i < range.getEnd(); i++) {
+                final Object itemId = datasource.getIdByIndex(i);
+                final Item item = datasource.getItem(itemId);
+                final GridValueChangeListener listener = valueChangeListeners
+                        .remove(itemId);
+
+                if (listener != null) {
+                    for (final Object propertyId : item.getItemPropertyIds()) {
+                        final Property<?> property = item
+                                .getItemProperty(propertyId);
+
+                        /*
+                         * Because listener != null, we can be certain that this
+                         * property is a ValueChangeNotifier: It wouldn't be
+                         * inserted in addValueChangeListeners if the property
+                         * wasn't a suitable type. I.e. No need for "instanceof"
+                         * check.
+                         */
+                        ((ValueChangeNotifier) property)
+                                .removeValueChangeListener(listener);
+                    }
+                }
+            }
+        }
+
+        public void clear() {
+            removeValueChangeListeners(activeRange);
+            /*
+             * we're doing an assert for emptiness there (instead of a
+             * carte-blanche ".clear()"), to be absolutely sure that everything
+             * is cleaned up properly, and that we have no dangling listeners.
+             */
+            assert valueChangeListeners.isEmpty() : "GridValueChangeListeners are leaking";
+
+            activeRange = Range.withLength(0, 0);
+        }
+
+        /**
+         * Manages removed properties in active rows.
+         * 
+         * @param removedPropertyIds
+         *            the property ids that have been removed from the container
+         */
+        public void propertiesRemoved(Collection<Object> removedPropertyIds) {
+            /*
+             * no-op, for now.
+             * 
+             * The Container should be responsible for cleaning out any
+             * ValueChangeListeners from removed Properties. Components will
+             * benefit from this, however.
+             */
+        }
+
+        /**
+         * Manages added properties in active rows.
+         * 
+         * @param addedPropertyIds
+         *            the property ids that have been added to the container
+         */
+        public void propertiesAdded(Collection<Object> addedPropertyIds) {
+            for (int i = activeRange.getStart(); i < activeRange.getEnd(); i++) {
+                final Object itemId = datasource.getIdByIndex(i);
+                final Item item = datasource.getItem(itemId);
+                final GridValueChangeListener listener = valueChangeListeners
+                        .get(itemId);
+                assert (listener != null) : "a listener should've been pre-made by addValueChangeListeners";
+
+                for (final Object propertyId : addedPropertyIds) {
+                    final Property<?> property = item
+                            .getItemProperty(propertyId);
+                    if (property instanceof ValueChangeNotifier) {
+                        ((ValueChangeNotifier) property)
+                                .addValueChangeListener(listener);
+                    }
+                }
+            }
+        }
+
+        /**
+         * Handles the insertion of rows.
+         * <p>
+         * This method's responsibilities are to:
+         * <ul>
+         * <li>shift the internal bookkeeping by <code>count</code> if the
+         * insertion happens above currently active range
+         * <li>ignore rows inserted below the currently active range
+         * <li>shift (and deactivate) rows pushed out of view
+         * <li>activate rows that are inserted in the current viewport
+         * </ul>
+         * 
+         * @param firstIndex
+         *            the index of the first inserted rows
+         * @param count
+         *            the number of rows inserted at <code>firstIndex</code>
+         */
+        public void insertRows(int firstIndex, int count) {
+            if (firstIndex < activeRange.getStart()) {
+                activeRange = activeRange.offsetBy(count);
+            } else if (firstIndex < activeRange.getEnd()) {
+                final Range deprecatedRange = Range.withLength(
+                        activeRange.getEnd(), count);
+                removeValueChangeListeners(deprecatedRange);
+
+                final Range freshRange = Range.between(firstIndex, count);
+                addValueChangeListeners(freshRange);
+            } else {
+                // out of view, noop
+            }
+        }
+
+        /**
+         * Removes a single item by its id.
+         * 
+         * @param itemId
+         *            the id of the removed id. <em>Note:</em> this item does
+         *            not exist anymore in the datasource
+         */
+        public void removeItemId(Object itemId) {
+            final GridValueChangeListener removedListener = valueChangeListeners
+                    .remove(itemId);
+            if (removedListener != null) {
+                /*
+                 * We removed an item from somewhere in the visible range, so we
+                 * make the active range shorter. The empty hole will be filled
+                 * by the client-side code when it asks for more information.
+                 */
+                activeRange = Range.withLength(activeRange.getStart(),
+                        activeRange.length() - 1);
+            }
+        }
+    }
+
+    /**
+     * A class to listen to changes in property values in the Container added
+     * with {@link Grid#setContainerDatasource(Container.Indexed)}, and notifies
+     * the data source to update the client-side representation of the modified
+     * item.
+     * <p>
+     * One instance of this class can (and should) be reused for all the
+     * properties in an item, since this class will inform that the entire row
+     * needs to be re-evaluated (in contrast to a property-based change
+     * management)
+     * <p>
+     * Since there's no Container-wide possibility to listen to any kind of
+     * value changes, an instance of this class needs to be attached to each and
+     * every Item's Property in the container.
+     * 
+     * @see Grid#addValueChangeListener(Container, Object, Object)
+     * @see Grid#valueChangeListeners
+     */
+    private class GridValueChangeListener implements ValueChangeListener {
+        private final Object itemId;
+
+        public GridValueChangeListener(Object itemId) {
+            /*
+             * Using an assert instead of an exception throw, just to optimize
+             * prematurely
+             */
+            assert itemId != null : "null itemId not accepted";
+            this.itemId = itemId;
+        }
+
+        @Override
+        public void valueChange(ValueChangeEvent event) {
+            datasourceExtension.updateRowData(datasource.indexOfId(itemId));
+        }
+    }
+
+    /**
      * The data source attached to the grid
      */
     private Container.Indexed datasource;
@@ -98,13 +387,17 @@ public class Grid extends AbstractComponent {
                 columnKeys.remove(columnId);
                 getState().columns.remove(column.getState());
             }
+            activeRowHandler.propertiesRemoved(removedColumns);
 
             // Add new columns
+            HashSet<Object> addedPropertyIds = new HashSet<Object>();
             for (Object propertyId : properties) {
                 if (!columns.containsKey(propertyId)) {
                     appendColumn(propertyId);
+                    addedPropertyIds.add(propertyId);
                 }
             }
+            activeRowHandler.propertiesAdded(addedPropertyIds);
 
             Object frozenPropertyId = columnKeys
                     .get(getState(false).lastFrozenColumnId);
@@ -114,8 +407,53 @@ public class Grid extends AbstractComponent {
         }
     };
 
+    private ItemSetChangeListener itemListener = new ItemSetChangeListener() {
+        @Override
+        public void containerItemSetChange(ItemSetChangeEvent event) {
+
+            if (event instanceof ItemAddEvent) {
+                ItemAddEvent addEvent = (ItemAddEvent) event;
+                int firstIndex = addEvent.getFirstIndex();
+                int count = addEvent.getAddedItemsCount();
+                datasourceExtension.insertRowData(firstIndex, count);
+                activeRowHandler.insertRows(firstIndex, count);
+            }
+
+            else if (event instanceof ItemRemoveEvent) {
+                ItemRemoveEvent removeEvent = (ItemRemoveEvent) event;
+                int firstIndex = removeEvent.getFirstIndex();
+                int count = removeEvent.getRemovedItemsCount();
+                datasourceExtension.removeRowData(firstIndex, count);
+
+                /*
+                 * Unfortunately, there's no sane way of getting the rest of the
+                 * removed itemIds.
+                 * 
+                 * Fortunately, the only time _currently_ an event with more
+                 * than one removed item seems to be when calling
+                 * AbstractInMemoryContainer.removeAllElements(). Otherwise,
+                 * it's only removing one item at a time.
+                 * 
+                 * We _could_ have a backup of all the itemIds, and compare to
+                 * that one, but we really really don't want to go there.
+                 */
+                activeRowHandler.removeItemId(removeEvent.getFirstItemId());
+            }
+
+            else {
+                // TODO no diff info available, redraw everything
+                throw new UnsupportedOperationException("bare "
+                        + "ItemSetChangeEvents are currently "
+                        + "not supported, use a container that "
+                        + "uses AddItemEvents and RemoveItemEvents.");
+            }
+        }
+    };
+
     private RpcDataProviderExtension datasourceExtension;
 
+    private final ActiveRowHandler activeRowHandler = new ActiveRowHandler();
+
     /**
      * Creates a new Grid using the given datasource.
      * 
@@ -124,6 +462,14 @@ public class Grid extends AbstractComponent {
      */
     public Grid(Container.Indexed datasource) {
         setContainerDatasource(datasource);
+
+        registerRpc(new GridServerRpc() {
+            @Override
+            public void setVisibleRows(int firstVisibleRow, int visibleRowCount) {
+                activeRowHandler
+                        .setActiveRows(firstVisibleRow, visibleRowCount);
+            }
+        });
     }
 
     /**
@@ -143,11 +489,16 @@ public class Grid extends AbstractComponent {
             return;
         }
 
-        // Remove old listener
+        // Remove old listeners
         if (datasource instanceof PropertySetChangeNotifier) {
             ((PropertySetChangeNotifier) datasource)
                     .removePropertySetChangeListener(propertyListener);
         }
+        if (datasource instanceof ItemSetChangeNotifier) {
+            ((ItemSetChangeNotifier) datasource)
+                    .removeItemSetChangeListener(itemListener);
+        }
+        activeRowHandler.clear();
 
         if (datasourceExtension != null) {
             removeExtension(datasourceExtension);
@@ -162,6 +513,15 @@ public class Grid extends AbstractComponent {
             ((PropertySetChangeNotifier) datasource)
                     .addPropertySetChangeListener(propertyListener);
         }
+        if (datasource instanceof ItemSetChangeNotifier) {
+            ((ItemSetChangeNotifier) datasource)
+                    .addItemSetChangeListener(itemListener);
+        }
+        /*
+         * 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.
+         */
 
         getState().columns.clear();
         setLastFrozenPropertyId(null);