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1 /*******************************************************************************
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2 * Copyright (c) 2008 Matthew Hall 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 * Matthew Hall - initial API and implementation (bug 215531)
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10 * Matthew Hall - bug 226765
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11 ******************************************************************************/
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12
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13 module org.eclipse.jface.internal.databinding.viewers.ObservableCollectionContentProvider;
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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 org.eclipse.core.databinding.observable.IObservable;
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18 import org.eclipse.core.databinding.observable.IObservableCollection;
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19 import org.eclipse.core.databinding.observable.Observables;
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20 import org.eclipse.core.databinding.observable.Realm;
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21 import org.eclipse.core.databinding.observable.masterdetail.IObservableFactory;
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22 import org.eclipse.core.databinding.observable.masterdetail.MasterDetailObservables;
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23 import org.eclipse.core.databinding.observable.set.IObservableSet;
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24 import org.eclipse.core.databinding.observable.value.IObservableValue;
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25 import org.eclipse.core.databinding.observable.value.WritableValue;
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26 import org.eclipse.core.runtime.Assert;
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27 import org.eclipse.jface.databinding.swt.SWTObservables;
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28 import org.eclipse.jface.viewers.AbstractListViewer;
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29 import org.eclipse.jface.viewers.AbstractTableViewer;
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30 import org.eclipse.jface.viewers.IElementComparer;
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31 import org.eclipse.jface.viewers.IStructuredContentProvider;
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32 import org.eclipse.jface.viewers.StructuredViewer;
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33 import org.eclipse.jface.viewers.Viewer;
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34 import org.eclipse.swt.widgets.Display;
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35
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36 /**
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37 * NON-API - Abstract base class for content providers where the viewer input is
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38 * expected to be an {@link IObservableCollection}.
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39 *
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40 * @since 1.2
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41 */
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42 public abstract class ObservableCollectionContentProvider :
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43 IStructuredContentProvider {
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44 private IObservableValue viewerObservable;
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45
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46 /**
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47 * Element comparer used by the viewer (may be null).
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48 */
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49 protected IElementComparer comparer;
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50
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51 /**
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52 * Interface for sending updates to the viewer.
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53 */
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54 protected ViewerUpdater viewerUpdater;
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55
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56 /**
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57 * Observable set of all elements known to the content provider. Subclasses
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58 * must add new elements to this set <b>before</b> adding them to the
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59 * viewer, and must remove old elements from this set <b>after</b> removing
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60 * them from the viewer.
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61 */
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62 protected IObservableSet knownElements;
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63
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64 private IObservableSet unmodifiableKnownElements;
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65 private IObservableCollection observableCollection;
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66
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67 /**
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68 * Constructs an ObservableCollectionContentProvider
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69 */
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70 protected this() {
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71 final Realm realm = SWTObservables.getRealm(Display.getDefault());
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72 viewerObservable = new WritableValue(realm);
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73 viewerUpdater = null;
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74
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75 // Known elements is a detail set of viewerObservable, so that when we
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76 // get the viewer instance we can swap in a set that uses its
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77 // IElementComparer, if any.
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78 IObservableFactory knownElementsFactory = new class() IObservableFactory {
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79 public IObservable createObservable(Object target) {
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80 IElementComparer comparer = null;
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81 if (null !is cast(StructuredViewer)target)
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82 comparer = (cast(StructuredViewer) target).getComparer();
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83 return ObservableViewerElementSet.withComparer(realm, null,
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84 comparer);
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85 }
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86 };
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87 knownElements = MasterDetailObservables.detailSet(viewerObservable,
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88 knownElementsFactory, null);
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89 unmodifiableKnownElements = Observables
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90 .unmodifiableObservableSet(knownElements);
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91
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92 observableCollection = null;
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93 }
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94
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95 public Object[] getElements(Object inputElement) {
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96 if (observableCollection is null)
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97 return new Object[0];
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98 return observableCollection.toArray();
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99 }
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100
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101 public void dispose() {
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102 if (observableCollection !is null)
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103 removeCollectionChangeListener(observableCollection);
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104
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105 if (viewerObservable !is null) {
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106 viewerObservable.setValue(null);
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107 viewerObservable.dispose();
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108 viewerObservable = null;
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109 }
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110 viewerUpdater = null;
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111 knownElements = null;
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112 unmodifiableKnownElements = null;
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113 }
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114
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115 public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
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116 setViewer(viewer);
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117 setInput(newInput);
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118 }
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119
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120 private void setViewer(Viewer viewer) {
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121 viewerUpdater = createViewerUpdater(viewer);
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122 comparer = getElementComparer(viewer);
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123 viewerObservable.setValue(viewer); // (clears knownElements)
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124 }
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125
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126 private static IElementComparer getElementComparer(Viewer viewer) {
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127 if (null !is cast(StructuredViewer)viewer)
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128 return (cast(StructuredViewer) viewer).getComparer();
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129 return null;
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130 }
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131
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132 ViewerUpdater createViewerUpdater(Viewer viewer) {
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133 if (null !is cast(AbstractListViewer)viewer)
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134 return new ListViewerUpdater(cast(AbstractListViewer) viewer);
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135 if (null !is cast(AbstractTableViewer)viewer)
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136 return new TableViewerUpdater(cast(AbstractTableViewer) viewer);
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137 throw new IllegalArgumentException(
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138 "This content provider only works with AbstractTableViewer or AbstractListViewer"); //$NON-NLS-1$
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139 }
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140
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141 void setInput(Object input) {
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142 if (observableCollection !is null) {
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143 removeCollectionChangeListener(observableCollection);
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144 observableCollection = null;
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145 }
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146
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147 if (input !is null) {
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148 checkInput(input);
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149 Assert.isTrue(null !is cast(IObservableCollection)input,
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150 "Input must be an IObservableCollection"); //$NON-NLS-1$
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151 observableCollection = cast(IObservableCollection) input;
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152 addCollectionChangeListener(observableCollection);
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153 knownElements.addAll(observableCollection);
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154 }
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155 }
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156
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157 /**
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158 * Throws an exception if the input is not the correct type.
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159 *
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160 * @param input
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161 * the input to check
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162 */
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163 protected abstract void checkInput(Object input);
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164
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165 /**
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166 * Register for change event notification from the given collection.
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167 *
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168 * @param collection
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169 * observable collection to listen to
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170 */
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171 protected abstract void addCollectionChangeListener(
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172 IObservableCollection collection);
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173
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174 /**
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175 * Deregisters from change events notification on the given collection.
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176 *
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177 * @param collection
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178 * observable collection to stop listening to
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179 */
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180 protected abstract void removeCollectionChangeListener(
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181 IObservableCollection collection);
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182
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183 /**
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184 * Returns whether the viewer is disposed. Collection change listeners in
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185 * subclasses should verify that the viewer is not disposed before sending
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186 * any updates to the {@link ViewerUpdater viewer updater}.
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187 *
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188 * @return whether the viewer is disposed.
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189 */
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190 protected final bool isViewerDisposed() {
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191 Viewer viewer = cast(Viewer) viewerObservable.getValue();
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192 return viewer is null || viewer.getControl() is null
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193 || viewer.getControl().isDisposed();
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194 }
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195
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196 /**
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197 * Returns the set of elements known to this content provider. Label
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198 * providers may track this set if they need to be notified about additions
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199 * before the viewer sees the added element, and notified about removals
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200 * after the element was removed from the viewer. This is intended for use
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201 * by label providers, as it will always return the items that need labels.
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202 *
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203 * @return unmodifiable observable set of items that will need labels
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204 */
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205 public IObservableSet getKnownElements() {
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206 return unmodifiableKnownElements;
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207 }
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208 }
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