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comparison org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/provisional/swt/TableUpdater.d @ 78:0a55d2d5a946

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Added file for databinding
author Frank Benoit <benoit@tionex.de>
date Tue, 14 Apr 2009 11:35:29 +0200
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76:f05e6e8b2f2d 78:0a55d2d5a946
1 /*******************************************************************************
2 * Copyright (c) 2005, 2008 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 *******************************************************************************/
11 module org.eclipse.jface.internal.databinding.provisional.swt.TableUpdater;
12
13 import java.lang.all;
14
15 import org.eclipse.core.databinding.observable.ChangeEvent;
16 import org.eclipse.core.databinding.observable.IChangeListener;
17 import org.eclipse.core.databinding.observable.IObservable;
18 import org.eclipse.core.databinding.observable.ObservableTracker;
19 import org.eclipse.core.databinding.observable.list.IListChangeListener;
20 import org.eclipse.core.databinding.observable.list.IObservableList;
21 import org.eclipse.core.databinding.observable.list.ListChangeEvent;
22 import org.eclipse.core.databinding.observable.list.ListDiffEntry;
23 import org.eclipse.core.runtime.Assert;
24 import org.eclipse.swt.SWT;
25 import org.eclipse.swt.events.DisposeEvent;
26 import org.eclipse.swt.events.DisposeListener;
27 import org.eclipse.swt.widgets.Event;
28 import org.eclipse.swt.widgets.Listener;
29 import org.eclipse.swt.widgets.Table;
30 import org.eclipse.swt.widgets.TableItem;
31
32 /**
33 * NON-API - This class can be used to update a table with automatic dependency
34 * tracking.
35 *
36 * @since 1.1
37 *
38 * @noextend This class is not intended to be subclassed by clients. (We do
39 * encourage experimentation for non-production code and are
40 * interested in feedback though.)
41 *
42 */
43 public abstract class TableUpdater {
44
45 private class UpdateRunnable : Runnable, IChangeListener,
46 DisposeListener {
47 private TableItem item;
48
49 private bool dirty = false;
50
51 private IObservable[] dependencies = new IObservable[0];
52
53 private final Object element;
54
55 this(TableItem item, Object element) {
56 this.item = item;
57 this.element = element;
58 item.addDisposeListener(this);
59 }
60
61 // Runnable implementation. This method runs at most once per repaint
62 // whenever the
63 // value gets marked as dirty.
64 public void run() {
65 if (table !is null && !table.isDisposed() && item !is null
66 && !item.isDisposed()) {
67 if (table.isVisible()) {
68 int tableHeight = table.getClientArea().height;
69 int numVisibleItems = tableHeight / table.getItemHeight();
70 int indexOfItem = table.indexOf(item);
71 int topIndex = table.getTopIndex();
72 if (indexOfItem >= topIndex
73 && indexOfItem <= topIndex + numVisibleItems) {
74 updateIfNecessary(indexOfItem);
75 return;
76 }
77 }
78 table.clear(table.indexOf(item));
79 }
80 }
81
82 private void updateIfNecessary(int indexOfItem) {
83 if (dirty) {
84 dependencies = ObservableTracker.runAndMonitor(dgRunnable( (int indexOfItem_) {
85 updateItem(indexOfItem_, item, element);
86 }, indexOfItem), this, null);
87 dirty = false;
88 }
89 }
90
91 // IChangeListener implementation (listening to the ComputedValue)
92 public void handleChange(ChangeEvent event) {
93 // Whenever this updator becomes dirty, schedule the run() method
94 makeDirty();
95 }
96
97 protected final void makeDirty() {
98 if (!dirty) {
99 dirty = true;
100 stopListening();
101 SWTUtil.runOnce(table.getDisplay(), this);
102 }
103 }
104
105 private void stopListening() {
106 // Stop listening for dependency changes
107 for (int i = 0; i < dependencies.length; i++) {
108 IObservable observable = dependencies[i];
109
110 observable.removeChangeListener(this);
111 }
112 }
113
114 // DisposeListener implementation
115 public void widgetDisposed(DisposeEvent e) {
116 stopListening();
117 dependencies = null;
118 item = null;
119 }
120 }
121
122 private class PrivateInterface : Listener, DisposeListener {
123
124 // Listener implementation
125 public void handleEvent(Event e) {
126 if (e.type is SWT.SetData) {
127 UpdateRunnable runnable = cast(UpdateRunnable) e.item.getData();
128 if (runnable is null) {
129 runnable = new UpdateRunnable(cast(TableItem) e.item, list.get(e.index));
130 e.item.setData(runnable);
131 runnable.makeDirty();
132 } else {
133 runnable.updateIfNecessary(e.index);
134 }
135 }
136 }
137
138 // DisposeListener implementation
139 public void widgetDisposed(DisposeEvent e) {
140 this.outer.dispose();
141 }
142
143 }
144
145 private PrivateInterface privateInterface = new PrivateInterface();
146
147 private Table table;
148
149 private IListChangeListener listChangeListener = new class() IListChangeListener {
150 public void handleListChange(ListChangeEvent event) {
151 ListDiffEntry[] differences = event.diff.getDifferences();
152 for (int i = 0; i < differences.length; i++) {
153 ListDiffEntry entry = differences[i];
154 if (entry.isAddition()) {
155 TableItem item = new TableItem(table, SWT.NONE, entry
156 .getPosition());
157 UpdateRunnable updateRunnable = new UpdateRunnable(item, entry.getElement());
158 item.setData(updateRunnable);
159 updateRunnable.makeDirty();
160 } else {
161 table.getItem(entry.getPosition()).dispose();
162 }
163 }
164 }
165 };
166
167 private IObservableList list;
168
169 /**
170 * Creates an updator for the given control.
171 *
172 * @param table
173 * table to update
174 * @param list
175 * @since 1.2
176 */
177 public this(Table table, IObservableList list) {
178 this.table = table;
179 this.list = list;
180 Assert.isLegal((table.getStyle() & SWT.VIRTUAL) !is 0,
181 "TableUpdater requires virtual table"); //$NON-NLS-1$
182
183 table.setItemCount(list.size());
184 list.addListChangeListener(listChangeListener);
185
186 table.addDisposeListener(privateInterface);
187 table.addListener(SWT.SetData, privateInterface);
188 }
189
190 /**
191 * This is called automatically when the control is disposed. It may also be
192 * called explicitly to remove this updator from the control. Subclasses
193 * will normally extend this method to detach any listeners they attached in
194 * their constructor.
195 */
196 public void dispose() {
197 table.removeDisposeListener(privateInterface);
198 table.removeListener(SWT.SetData, privateInterface);
199 list.removeListChangeListener(listChangeListener);
200 table = null;
201 list = null;
202 }
203
204 /**
205 * Updates the control. This method will be invoked once after the updator
206 * is created, and once before any repaint during which the control is
207 * visible and dirty.
208 *
209 * <p>
210 * Subclasses should overload this method to provide any code that changes
211 * the appearance of the widget.
212 * </p>
213 *
214 * @param index
215 * @param item
216 * the item to update
217 * @param element
218 * @since 1.2
219 */
220 protected abstract void updateItem(int index, TableItem item, Object element);
221
222 }