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comparison org.eclipse.core.databinding.observable/src/org/eclipse/core/databinding/observable/map/ComputedObservableMap.d @ 95:6208d4f6a277

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Added trees for databinding.beans and observable
author Frank Benoit <benoit@tionex.de>
date Tue, 21 Apr 2009 10:55:51 +0200
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children b74ac5dfcc06
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94:1d37a7813832 95:6208d4f6a277
1 /*******************************************************************************
2 * Copyright (c) 2006, 2007 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
12 package org.eclipse.core.databinding.observable.map;
13
14 import java.util.AbstractSet;
15 import java.util.Collections;
16 import java.util.HashMap;
17 import java.util.HashSet;
18 import java.util.Iterator;
19 import java.util.Map;
20 import java.util.Set;
21
22 import org.eclipse.core.databinding.observable.Diffs;
23 import org.eclipse.core.databinding.observable.set.IObservableSet;
24 import org.eclipse.core.databinding.observable.set.ISetChangeListener;
25 import org.eclipse.core.databinding.observable.set.SetChangeEvent;
26
27 /**
28 * Maps objects to one of their attributes. Tracks changes to the underlying
29 * observable set of objects (keys), as well as changes to attribute values.
30 */
31 public abstract class ComputedObservableMap : AbstractObservableMap {
32
33 private final IObservableSet keySet;
34
35 private ISetChangeListener setChangeListener = new class() ISetChangeListener {
36 public void handleSetChange(SetChangeEvent event) {
37 Set addedKeys = new HashSet(event.diff.getAdditions());
38 Set removedKeys = new HashSet(event.diff.getRemovals());
39 Map oldValues = new HashMap();
40 Map newValues = new HashMap();
41 for (Iterator it = removedKeys.iterator(); it.hasNext();) {
42 Object removedKey = it.next();
43 Object oldValue = doGet(removedKey);
44 unhookListener(removedKey);
45 if (oldValue !is null) {
46 oldValues.put(removedKey, oldValue);
47 }
48 }
49 for (Iterator it = addedKeys.iterator(); it.hasNext();) {
50 Object addedKey = it.next();
51 hookListener(addedKey);
52 Object newValue = doGet(addedKey);
53 newValues.put(addedKey, newValue);
54 }
55 fireMapChange(Diffs.createMapDiff(addedKeys, removedKeys,
56 Collections.EMPTY_SET, oldValues, newValues));
57 }
58 };
59
60 private Set entrySet = new EntrySet();
61
62 private class EntrySet : AbstractSet {
63
64 public Iterator iterator() {
65 final Iterator keyIterator = keySet.iterator();
66 return new class() Iterator {
67
68 public bool hasNext() {
69 return keyIterator.hasNext();
70 }
71
72 public Object next() {
73 final Object key = keyIterator.next();
74 return new Map.Entry() {
75
76 public Object getKey() {
77 return key;
78 }
79
80 public Object getValue() {
81 return get(getKey());
82 }
83
84 public Object setValue(Object value) {
85 return put(getKey(), value);
86 }
87 };
88 }
89
90 public void remove() {
91 keyIterator.remove();
92 }
93 };
94 }
95
96 public int size() {
97 return keySet.size();
98 }
99
100 }
101
102 /**
103 * @param keySet
104 */
105 public this(IObservableSet keySet) {
106 super(keySet.getRealm());
107 this.keySet = keySet;
108 this.keySet.addSetChangeListener(setChangeListener);
109 }
110
111 protected void init() {
112 for (Iterator it = this.keySet.iterator(); it.hasNext();) {
113 Object key = it.next();
114 hookListener(key);
115 }
116 }
117
118 protected final void fireSingleChange(Object key, Object oldValue,
119 Object newValue) {
120 fireMapChange(Diffs.createMapDiffSingleChange(key, oldValue, newValue));
121 }
122
123 public Set entrySet() {
124 return entrySet;
125 }
126
127 public Set keySet() {
128 return keySet;
129 }
130
131 final public Object get(Object key) {
132 return doGet(key);
133 }
134
135 final public Object put(Object key, Object value) {
136 return doPut(key, value);
137 }
138
139 /**
140 * @param removedKey
141 */
142 protected abstract void unhookListener(Object removedKey);
143
144 /**
145 * @param addedKey
146 */
147 protected abstract void hookListener(Object addedKey);
148
149 /**
150 * @param key
151 * @return the value for the given key
152 */
153 protected abstract Object doGet(Object key);
154
155 /**
156 * @param key
157 * @param value
158 * @return the old value for the given key
159 */
160 protected abstract Object doPut(Object key, Object value);
161 }