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Java > Open Source Codes > org > eclipse > jface > internal > databinding > provisional > 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.internal.databinding.provisional.viewers;
13
14 import java.util.Iterator JavaDoc;
15
16 import org.eclipse.jface.internal.databinding.provisional.observable.set.IObservableSet;
17 import org.eclipse.jface.internal.databinding.provisional.observable.set.ISetChangeListener;
18 import org.eclipse.jface.internal.databinding.provisional.observable.set.SetDiff;
19
20 /**
21  * @since 1.0
22  *
23  */

24 public abstract class ListeningLabelProvider extends ViewerLabelProvider {
25
26     private ISetChangeListener listener = new ISetChangeListener() {
27         public void handleSetChange(IObservableSet source, SetDiff diff) {
28             for (Iterator JavaDoc it = diff.getAdditions().iterator(); it.hasNext();) {
29                 addListenerTo(it.next());
30             }
31             for (Iterator JavaDoc it = diff.getRemovals().iterator(); it.hasNext();) {
32                 removeListenerFrom(it.next());
33             }
34         }
35     };
36
37     private IObservableSet items;
38
39     /**
40      * @param itemsThatNeedLabels
41      */

42     public ListeningLabelProvider(IObservableSet itemsThatNeedLabels) {
43         this.items = itemsThatNeedLabels;
44         items.addSetChangeListener(listener);
45         for (Iterator JavaDoc it = items.iterator(); it.hasNext();) {
46             addListenerTo(it.next());
47         }
48     }
49
50     /**
51      * @param next
52      */

53     protected abstract void removeListenerFrom(Object JavaDoc next);
54
55     /**
56      * @param next
57      */

58     protected abstract void addListenerTo(Object JavaDoc next);
59
60     public void dispose() {
61         for (Iterator JavaDoc iter = items.iterator(); iter.hasNext();) {
62             removeListenerFrom(iter.next());
63         }
64         items.removeSetChangeListener(listener);
65         super.dispose();
66     }
67 }
68
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