Mercurial > projects > dwt2

comparison org.eclipse.core.databinding/src/org/eclipse/core/internal/databinding/observable/StalenessTracker.d @ 78:0a55d2d5a946

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added file for databinding
author Frank Benoit <benoit@tionex.de>
date Tue, 14 Apr 2009 11:35:29 +0200
parents
children 383ce7bd736b
comparison
equal deleted inserted replaced
76:f05e6e8b2f2d 78:0a55d2d5a946
1 /*******************************************************************************
2 * Copyright (c) 2006 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 module org.eclipse.core.internal.databinding.observable.StalenessTracker;
13
14 import java.lang.all;
15
16 import java.util.HashMap;
17 import java.util.Map;
18
19 import org.eclipse.core.databinding.observable.ChangeEvent;
20 import org.eclipse.core.databinding.observable.IChangeListener;
21 import org.eclipse.core.databinding.observable.IObservable;
22 import org.eclipse.core.databinding.observable.IStaleListener;
23 import org.eclipse.core.databinding.observable.StaleEvent;
24 import org.eclipse.core.internal.databinding.IdentityWrapper;
25
26 /**
27 * @since 1.0
28 *
29 */
30 public class StalenessTracker {
31
32 private Map staleMap = new HashMap();
33
34 private int staleCount = 0;
35
36 private final IStalenessConsumer stalenessConsumer;
37
38 private class ChildListener : IStaleListener, IChangeListener {
39 public void handleStale(StaleEvent event) {
40 processStalenessChange(cast(IObservable) event.getSource(), true);
41 }
42
43 public void handleChange(ChangeEvent event) {
44 processStalenessChange(cast(IObservable) event.getSource(), true);
45 }
46 }
47
48 private ChildListener childListener = new ChildListener();
49
50 /**
51 * @param observables
52 * @param stalenessConsumer
53 */
54 public this(IObservable[] observables,
55 IStalenessConsumer stalenessConsumer) {
56 this.stalenessConsumer = stalenessConsumer;
57 for (int i = 0; i < observables.length; i++) {
58 IObservable observable = observables[i];
59 doAddObservable(observable, false);
60 }
61 stalenessConsumer.setStale(staleCount > 0);
62 }
63
64 /**
65 * @param child
66 * @param callback
67 */
68 public void processStalenessChange(IObservable child, bool callback) {
69 bool oldStale = staleCount > 0;
70 IdentityWrapper wrappedChild = new IdentityWrapper(child);
71 bool oldChildStale = getOldChildStale(wrappedChild);
72 bool newChildStale = child.isStale();
73 if (oldChildStale !is newChildStale) {
74 if (oldChildStale) {
75 staleCount--;
76 } else {
77 staleCount++;
78 }
79 staleMap.put(wrappedChild, newChildStale ? Boolean.TRUE : Boolean.FALSE);
80 }
81 bool newStale = staleCount > 0;
82 if (callback && (newStale !is oldStale)) {
83 stalenessConsumer.setStale(newStale);
84 }
85 }
86
87 /**
88 * @param wrappedChild
89 */
90 private bool getOldChildStale(IdentityWrapper wrappedChild) {
91 Object oldChildValue = staleMap.get(wrappedChild);
92 bool oldChildStale = oldChildValue is null ? false
93 : (cast(Boolean) oldChildValue).booleanValue();
94 return oldChildStale;
95 }
96
97 /**
98 * @param observable
99 */
100 public void addObservable(IObservable observable) {
101 doAddObservable(observable, true);
102 }
103
104 private void doAddObservable(IObservable observable, bool callback) {
105 processStalenessChange(observable, callback);
106 observable.addChangeListener(childListener);
107 observable.addStaleListener(childListener);
108 }
109
110 /**
111 * @param observable
112 */
113 public void removeObservable(IObservable observable) {
114 bool oldStale = staleCount > 0;
115 IdentityWrapper wrappedChild = new IdentityWrapper(observable);
116 bool oldChildStale = getOldChildStale(wrappedChild);
117 if (oldChildStale) {
118 staleCount--;
119 }
120 staleMap.remove(wrappedChild);
121 observable.removeChangeListener(childListener);
122 observable.removeStaleListener(childListener);
123 bool newStale = staleCount > 0;
124 if (newStale !is oldStale) {
125 stalenessConsumer.setStale(newStale);
126 }
127 }
128
129 }