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comparison org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/viewers/ObservableCollectionContentProvider.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) 2008 Matthew Hall 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 * Matthew Hall - initial API and implementation (bug 215531)
10 * Matthew Hall - bug 226765
11 ******************************************************************************/
12
13 module org.eclipse.jface.internal.databinding.viewers.ObservableCollectionContentProvider;
14
15 import java.lang.all;
16
17 import org.eclipse.core.databinding.observable.IObservable;
18 import org.eclipse.core.databinding.observable.IObservableCollection;
19 import org.eclipse.core.databinding.observable.Observables;
20 import org.eclipse.core.databinding.observable.Realm;
21 import org.eclipse.core.databinding.observable.masterdetail.IObservableFactory;
22 import org.eclipse.core.databinding.observable.masterdetail.MasterDetailObservables;
23 import org.eclipse.core.databinding.observable.set.IObservableSet;
24 import org.eclipse.core.databinding.observable.value.IObservableValue;
25 import org.eclipse.core.databinding.observable.value.WritableValue;
26 import org.eclipse.core.runtime.Assert;
27 import org.eclipse.jface.databinding.swt.SWTObservables;
28 import org.eclipse.jface.viewers.AbstractListViewer;
29 import org.eclipse.jface.viewers.AbstractTableViewer;
30 import org.eclipse.jface.viewers.IElementComparer;
31 import org.eclipse.jface.viewers.IStructuredContentProvider;
32 import org.eclipse.jface.viewers.StructuredViewer;
33 import org.eclipse.jface.viewers.Viewer;
34 import org.eclipse.swt.widgets.Display;
35
36 /**
37 * NON-API - Abstract base class for content providers where the viewer input is
38 * expected to be an {@link IObservableCollection}.
39 *
40 * @since 1.2
41 */
42 public abstract class ObservableCollectionContentProvider :
43 IStructuredContentProvider {
44 private IObservableValue viewerObservable;
45
46 /**
47 * Element comparer used by the viewer (may be null).
48 */
49 protected IElementComparer comparer;
50
51 /**
52 * Interface for sending updates to the viewer.
53 */
54 protected ViewerUpdater viewerUpdater;
55
56 /**
57 * Observable set of all elements known to the content provider. Subclasses
58 * must add new elements to this set <b>before</b> adding them to the
59 * viewer, and must remove old elements from this set <b>after</b> removing
60 * them from the viewer.
61 */
62 protected IObservableSet knownElements;
63
64 private IObservableSet unmodifiableKnownElements;
65 private IObservableCollection observableCollection;
66
67 /**
68 * Constructs an ObservableCollectionContentProvider
69 */
70 protected this() {
71 final Realm realm = SWTObservables.getRealm(Display.getDefault());
72 viewerObservable = new WritableValue(realm);
73 viewerUpdater = null;
74
75 // Known elements is a detail set of viewerObservable, so that when we
76 // get the viewer instance we can swap in a set that uses its
77 // IElementComparer, if any.
78 IObservableFactory knownElementsFactory = new class() IObservableFactory {
79 public IObservable createObservable(Object target) {
80 IElementComparer comparer = null;
81 if (null !is cast(StructuredViewer)target)
82 comparer = (cast(StructuredViewer) target).getComparer();
83 return ObservableViewerElementSet.withComparer(realm, null,
84 comparer);
85 }
86 };
87 knownElements = MasterDetailObservables.detailSet(viewerObservable,
88 knownElementsFactory, null);
89 unmodifiableKnownElements = Observables
90 .unmodifiableObservableSet(knownElements);
91
92 observableCollection = null;
93 }
94
95 public Object[] getElements(Object inputElement) {
96 if (observableCollection is null)
97 return new Object[0];
98 return observableCollection.toArray();
99 }
100
101 public void dispose() {
102 if (observableCollection !is null)
103 removeCollectionChangeListener(observableCollection);
104
105 if (viewerObservable !is null) {
106 viewerObservable.setValue(null);
107 viewerObservable.dispose();
108 viewerObservable = null;
109 }
110 viewerUpdater = null;
111 knownElements = null;
112 unmodifiableKnownElements = null;
113 }
114
115 public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
116 setViewer(viewer);
117 setInput(newInput);
118 }
119
120 private void setViewer(Viewer viewer) {
121 viewerUpdater = createViewerUpdater(viewer);
122 comparer = getElementComparer(viewer);
123 viewerObservable.setValue(viewer); // (clears knownElements)
124 }
125
126 private static IElementComparer getElementComparer(Viewer viewer) {
127 if (null !is cast(StructuredViewer)viewer)
128 return (cast(StructuredViewer) viewer).getComparer();
129 return null;
130 }
131
132 ViewerUpdater createViewerUpdater(Viewer viewer) {
133 if (null !is cast(AbstractListViewer)viewer)
134 return new ListViewerUpdater(cast(AbstractListViewer) viewer);
135 if (null !is cast(AbstractTableViewer)viewer)
136 return new TableViewerUpdater(cast(AbstractTableViewer) viewer);
137 throw new IllegalArgumentException(
138 "This content provider only works with AbstractTableViewer or AbstractListViewer"); //$NON-NLS-1$
139 }
140
141 void setInput(Object input) {
142 if (observableCollection !is null) {
143 removeCollectionChangeListener(observableCollection);
144 observableCollection = null;
145 }
146
147 if (input !is null) {
148 checkInput(input);
149 Assert.isTrue(null !is cast(IObservableCollection)input,
150 "Input must be an IObservableCollection"); //$NON-NLS-1$
151 observableCollection = cast(IObservableCollection) input;
152 addCollectionChangeListener(observableCollection);
153 knownElements.addAll(observableCollection);
154 }
155 }
156
157 /**
158 * Throws an exception if the input is not the correct type.
159 *
160 * @param input
161 * the input to check
162 */
163 protected abstract void checkInput(Object input);
164
165 /**
166 * Register for change event notification from the given collection.
167 *
168 * @param collection
169 * observable collection to listen to
170 */
171 protected abstract void addCollectionChangeListener(
172 IObservableCollection collection);
173
174 /**
175 * Deregisters from change events notification on the given collection.
176 *
177 * @param collection
178 * observable collection to stop listening to
179 */
180 protected abstract void removeCollectionChangeListener(
181 IObservableCollection collection);
182
183 /**
184 * Returns whether the viewer is disposed. Collection change listeners in
185 * subclasses should verify that the viewer is not disposed before sending
186 * any updates to the {@link ViewerUpdater viewer updater}.
187 *
188 * @return whether the viewer is disposed.
189 */
190 protected final bool isViewerDisposed() {
191 Viewer viewer = cast(Viewer) viewerObservable.getValue();
192 return viewer is null || viewer.getControl() is null
193 || viewer.getControl().isDisposed();
194 }
195
196 /**
197 * Returns the set of elements known to this content provider. Label
198 * providers may track this set if they need to be notified about additions
199 * before the viewer sees the added element, and notified about removals
200 * after the element was removed from the viewer. This is intended for use
201 * by label providers, as it will always return the items that need labels.
202 *
203 * @return unmodifiable observable set of items that will need labels
204 */
205 public IObservableSet getKnownElements() {
206 return unmodifiableKnownElements;
207 }
208 }