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1
11
12 package org.eclipse.core.internal.databinding.observable;
13
14 import java.util.HashMap  ;
15 import java.util.Map ;
16
17 import org.eclipse.core.databinding.observable.ChangeEvent;
18 import org.eclipse.core.databinding.observable.IChangeListener;
19 import org.eclipse.core.databinding.observable.IObservable;
20 import org.eclipse.core.databinding.observable.IStaleListener;
21 import org.eclipse.core.databinding.observable.StaleEvent;
22 import org.eclipse.core.internal.databinding.IdentityWrapper;
23
24
28 public class StalenessTracker {
29
30 private Map staleMap = new HashMap ();
31
32 private int staleCount = 0;
33
34 private final IStalenessConsumer stalenessConsumer;
35
36 private class ChildListener implements IStaleListener, IChangeListener {
37 public void handleStale(StaleEvent event) {
38 processStalenessChange((IObservable) event.getSource(), true);
39 }
40
41 public void handleChange(ChangeEvent event) {
42 processStalenessChange((IObservable) event.getSource(), true);
43 }
44 }
45
46 private ChildListener childListener = new ChildListener();
47
48
52 public StalenessTracker(IObservable[] observables,
53 IStalenessConsumer stalenessConsumer) {
54 this.stalenessConsumer = stalenessConsumer;
55 for (int i = 0; i < observables.length; i++) {
56 IObservable observable = observables[i];
57 doAddObservable(observable, false);
58 }
59 stalenessConsumer.setStale(staleCount > 0);
60 }
61
62
66 public void processStalenessChange(IObservable child, boolean callback) {
67 boolean oldStale = staleCount > 0;
68 IdentityWrapper wrappedChild = new IdentityWrapper(child);
69 boolean oldChildStale = getOldChildStale(wrappedChild);
70 boolean newChildStale = child.isStale();
71 if (oldChildStale != newChildStale) {
72 if (oldChildStale) {
73 staleCount--;
74 } else {
75 staleCount++;
76 }
77 staleMap.put(wrappedChild, newChildStale ? Boolean.TRUE : Boolean.FALSE);
78 }
79 boolean newStale = staleCount > 0;
80 if (callback && (newStale != oldStale)) {
81 stalenessConsumer.setStale(newStale);
82 }
83 }
84
85
88 private boolean getOldChildStale(IdentityWrapper wrappedChild) {
89 Object oldChildValue = staleMap.get(wrappedChild);
90 boolean oldChildStale = oldChildValue == null ? false
91 : ((Boolean ) oldChildValue).booleanValue();
92 return oldChildStale;
93 }
94
95
98 public void addObservable(IObservable observable) {
99 doAddObservable(observable, true);
100 }
101
102 private void doAddObservable(IObservable observable, boolean callback) {
103 processStalenessChange(observable, callback);
104 observable.addChangeListener(childListener);
105 observable.addStaleListener(childListener);
106 }
107
108
111 public void removeObservable(IObservable observable) {
112 boolean oldStale = staleCount > 0;
113 IdentityWrapper wrappedChild = new IdentityWrapper(observable);
114 boolean oldChildStale = getOldChildStale(wrappedChild);
115 if (oldChildStale) {
116 staleCount--;
117 }
118 staleMap.remove(wrappedChild);
119 observable.removeChangeListener(childListener);
120 observable.removeStaleListener(childListener);
121 boolean newStale = staleCount > 0;
122 if (newStale != oldStale) {
123 stalenessConsumer.setStale(newStale);
124 }
125 }
126
127 }
128 |
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