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1 /*******************************************************************************
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2 * Copyright (c) 2006 IBM Corporation and others.
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3 * All rights reserved. This program and the accompanying materials
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4 * are made available under the terms of the Eclipse Public License v1.0
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5 * which accompanies this distribution, and is available at
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6 * http://www.eclipse.org/legal/epl-v10.html
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7 *
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8 * Contributors:
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9 * IBM Corporation - initial API and implementation
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10 ******************************************************************************/
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11
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12 module org.eclipse.core.internal.databinding.observable.StalenessTracker;
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81
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13 import org.eclipse.core.internal.databinding.observable.IStalenessConsumer;
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78
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14
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15 import java.lang.all;
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16
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17 import java.util.HashMap;
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18 import java.util.Map;
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19
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20 import org.eclipse.core.databinding.observable.ChangeEvent;
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21 import org.eclipse.core.databinding.observable.IChangeListener;
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22 import org.eclipse.core.databinding.observable.IObservable;
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23 import org.eclipse.core.databinding.observable.IStaleListener;
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24 import org.eclipse.core.databinding.observable.StaleEvent;
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25 import org.eclipse.core.internal.databinding.IdentityWrapper;
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26
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27 /**
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28 * @since 1.0
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29 *
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30 */
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31 public class StalenessTracker {
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32
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33 private Map staleMap = new HashMap();
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34
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35 private int staleCount = 0;
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36
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37 private final IStalenessConsumer stalenessConsumer;
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38
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39 private class ChildListener : IStaleListener, IChangeListener {
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40 public void handleStale(StaleEvent event) {
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41 processStalenessChange(cast(IObservable) event.getSource(), true);
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42 }
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43
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44 public void handleChange(ChangeEvent event) {
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45 processStalenessChange(cast(IObservable) event.getSource(), true);
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46 }
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47 }
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48
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49 private ChildListener childListener = new ChildListener();
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50
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51 /**
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52 * @param observables
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53 * @param stalenessConsumer
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54 */
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55 public this(IObservable[] observables,
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56 IStalenessConsumer stalenessConsumer) {
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57 this.stalenessConsumer = stalenessConsumer;
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58 for (int i = 0; i < observables.length; i++) {
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59 IObservable observable = observables[i];
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60 doAddObservable(observable, false);
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61 }
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62 stalenessConsumer.setStale(staleCount > 0);
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63 }
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64
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65 /**
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66 * @param child
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67 * @param callback
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68 */
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69 public void processStalenessChange(IObservable child, bool callback) {
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70 bool oldStale = staleCount > 0;
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71 IdentityWrapper wrappedChild = new IdentityWrapper(child);
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72 bool oldChildStale = getOldChildStale(wrappedChild);
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73 bool newChildStale = child.isStale();
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74 if (oldChildStale !is newChildStale) {
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75 if (oldChildStale) {
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76 staleCount--;
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77 } else {
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78 staleCount++;
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79 }
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80 staleMap.put(wrappedChild, newChildStale ? Boolean.TRUE : Boolean.FALSE);
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81 }
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82 bool newStale = staleCount > 0;
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83 if (callback && (newStale !is oldStale)) {
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84 stalenessConsumer.setStale(newStale);
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85 }
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86 }
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87
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88 /**
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89 * @param wrappedChild
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90 */
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91 private bool getOldChildStale(IdentityWrapper wrappedChild) {
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92 Object oldChildValue = staleMap.get(wrappedChild);
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93 bool oldChildStale = oldChildValue is null ? false
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94 : (cast(Boolean) oldChildValue).booleanValue();
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95 return oldChildStale;
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96 }
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97
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98 /**
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99 * @param observable
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100 */
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101 public void addObservable(IObservable observable) {
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102 doAddObservable(observable, true);
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103 }
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104
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105 private void doAddObservable(IObservable observable, bool callback) {
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106 processStalenessChange(observable, callback);
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107 observable.addChangeListener(childListener);
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108 observable.addStaleListener(childListener);
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109 }
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110
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111 /**
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112 * @param observable
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113 */
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114 public void removeObservable(IObservable observable) {
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115 bool oldStale = staleCount > 0;
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116 IdentityWrapper wrappedChild = new IdentityWrapper(observable);
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117 bool oldChildStale = getOldChildStale(wrappedChild);
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118 if (oldChildStale) {
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119 staleCount--;
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120 }
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121 staleMap.remove(wrappedChild);
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122 observable.removeChangeListener(childListener);
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123 observable.removeStaleListener(childListener);
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124 bool newStale = staleCount > 0;
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125 if (newStale !is oldStale) {
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126 stalenessConsumer.setStale(newStale);
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127 }
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128 }
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129
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130 }
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