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Java > Open Source Codes > org > eclipse > jface > databinding > viewers > ListeningLabelProvider


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 package org.eclipse.jface.databinding.viewers;
13
14 import java.util.Iterator JavaDoc;
15
16 import org.eclipse.core.databinding.observable.set.IObservableSet;
17 import org.eclipse.core.databinding.observable.set.ISetChangeListener;
18 import org.eclipse.core.databinding.observable.set.SetChangeEvent;
19 import org.eclipse.jface.internal.databinding.provisional.viewers.ViewerLabelProvider;
20
21 /**
22  * @since 1.1
23  *
24  */
25 public abstract class ListeningLabelProvider extends ViewerLabelProvider {
26
27     private ISetChangeListener listener = new ISetChangeListener() {
28         public void handleSetChange(SetChangeEvent event) {
29             for (Iterator JavaDoc it = event.diff.getAdditions().iterator(); it.hasNext();) {
30                 addListenerTo(it.next());
31             }
32             for (Iterator JavaDoc it = event.diff.getRemovals().iterator(); it.hasNext();) {
33                 removeListenerFrom(it.next());
34             }
35         }
36     };
37
38     private IObservableSet items;
39
40     /**
41      * @param itemsThatNeedLabels
42      */
43     public ListeningLabelProvider(IObservableSet itemsThatNeedLabels) {
44         this.items = itemsThatNeedLabels;
45         items.addSetChangeListener(listener);
46         for (Iterator JavaDoc it = items.iterator(); it.hasNext();) {
47             addListenerTo(it.next());
48         }
49     }
50
51     /**
52      * @param next
53      */
54     protected abstract void removeListenerFrom(Object JavaDoc next);
55
56     /**
57      * @param next
58      */
59     protected abstract void addListenerTo(Object JavaDoc next);
60
61     public void dispose() {
62         for (Iterator JavaDoc iter = items.iterator(); iter.hasNext();) {
63             removeListenerFrom(iter.next());
64         }
65         items.removeSetChangeListener(listener);
66         super.dispose();
67     }
68 }
69
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