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comparison org.eclipse.core.databinding/src/org/eclipse/core/internal/databinding/observable/MapEntryObservableValue.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 Marko Topolnik 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 * Marko Topolnik - initial API and implementation (bug 184830)
10 * Matthew Hall - bug 184830
11 ******************************************************************************/
12
13 module org.eclipse.core.internal.databinding.observable.MapEntryObservableValue;
14
15 import java.lang.all;
16
17 import org.eclipse.core.databinding.observable.Diffs;
18 import org.eclipse.core.databinding.observable.IStaleListener;
19 import org.eclipse.core.databinding.observable.ObservableTracker;
20 import org.eclipse.core.databinding.observable.StaleEvent;
21 import org.eclipse.core.databinding.observable.map.IMapChangeListener;
22 import org.eclipse.core.databinding.observable.map.IObservableMap;
23 import org.eclipse.core.databinding.observable.map.MapChangeEvent;
24 import org.eclipse.core.databinding.observable.value.AbstractObservableValue;
25 import org.eclipse.core.databinding.observable.value.IObservableValue;
26
27 /**
28 * An {@link IObservableValue} that tracks the value of an entry in an
29 * {@link IObservableMap}, identified by the entry's key.
30 *
31 * @since 1.1
32 */
33 public class MapEntryObservableValue : AbstractObservableValue {
34 private IObservableMap map;
35 private Object key;
36 private Object valueType;
37
38 private IMapChangeListener changeListener = new class() IMapChangeListener {
39 public void handleMapChange(MapChangeEvent event) {
40 if (event.diff.getAddedKeys().contains(key)) {
41 final Object newValue = event.diff.getNewValue(key);
42 if (newValue !is null) {
43 fireValueChange(Diffs.createValueDiff(null, newValue));
44 }
45 } else if (event.diff.getChangedKeys().contains(key)) {
46 fireValueChange(Diffs.createValueDiff(event.diff
47 .getOldValue(key), event.diff.getNewValue(key)));
48 } else if (event.diff.getRemovedKeys().contains(key)) {
49 final Object oldValue = event.diff.getOldValue(key);
50 if (oldValue !is null) {
51 fireValueChange(Diffs.createValueDiff(oldValue, null));
52 }
53 }
54 }
55 };
56
57 private IStaleListener staleListener = new class() IStaleListener {
58 public void handleStale(StaleEvent staleEvent) {
59 fireStale();
60 }
61 };
62
63 /**
64 * Creates a map entry observable.
65 *
66 * @param map
67 * the observable map whose entry will be tracked
68 * @param key
69 * the key identifying the entry whose value will be tracked
70 * @param valueType
71 * the type of the value
72 */
73 public this(IObservableMap map, Object key,
74 Object valueType) {
75 super(map.getRealm());
76 this.map = map;
77 this.key = key;
78 this.valueType = valueType;
79
80 map.addMapChangeListener(changeListener);
81 map.addStaleListener(staleListener);
82 }
83
84 public Object getValueType() {
85 return this.valueType;
86 }
87
88 public bool isStale() {
89 ObservableTracker.getterCalled(this);
90 return map.isStale();
91 }
92
93 public synchronized void dispose() {
94 if (map !is null) {
95 map.removeMapChangeListener(changeListener);
96 map.removeStaleListener(staleListener);
97 map = null;
98 changeListener = null;
99 staleListener = null;
100 }
101 super.dispose();
102 }
103
104 protected Object doGetValue() {
105 return this.map.get(this.key);
106 }
107
108 protected void doSetValue(Object value) {
109 this.map.put(this.key, value);
110 }
111 }