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Java > Open Source Codes > org > netbeans > editor > WeakTimerListener


1 /*
2  * The contents of this file are subject to the terms of the Common Development
3  * and Distribution License (the License). You may not use this file except in
4  * compliance with the License.
5  *
6  * You can obtain a copy of the License at http://www.netbeans.org/cddl.html
7  * or http://www.netbeans.org/cddl.txt.
8  *
9  * When distributing Covered Code, include this CDDL Header Notice in each file
10  * and include the License file at http://www.netbeans.org/cddl.txt.
11  * If applicable, add the following below the CDDL Header, with the fields
12  * enclosed by brackets [] replaced by your own identifying information:
13  * "Portions Copyrighted [year] [name of copyright owner]"
14  *
15  * The Original Software is NetBeans. The Initial Developer of the Original
16  * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
17  * Microsystems, Inc. All Rights Reserved.
18  */
19
20 package org.netbeans.editor;
21
22 import java.lang.ref.WeakReference JavaDoc;
23 import java.awt.event.ActionListener JavaDoc;
24 import java.awt.event.ActionEvent JavaDoc;
25 import javax.swing.Timer JavaDoc;
26
27 /**
28  * Action listener that has a weak reference
29  * to the source action listener so it doesn't prevent
30  * it to be garbage collected.
31  * The calls to the <code>actionPerformed</code> are automatically
32  * propagated to the source action listener.
33  *
34  * @author Miloslav Metelka
35  * @version 1.00
36  */
37
38 public class WeakTimerListener implements ActionListener JavaDoc {
39
40     private WeakReference JavaDoc ref;
41
42     private boolean stopTimer;
43
44     /** Construct new listener with automatic timer stopping.
45      */
46     public WeakTimerListener(ActionListener JavaDoc source) {
47         this(source, true);
48     }
49
50     /** Construct new listener.
51      * @param source source action listener to which this listener delegates.
52      * @param stopTimer whether the timer should be stopped automatically when
53      * the timer fires and the source listener was garbage collected.
54      */
55     public WeakTimerListener(ActionListener JavaDoc source, boolean stopTimer) {
56         this.ref = new WeakReference JavaDoc(source);
57         this.stopTimer = stopTimer;
58     }
59
60     public void actionPerformed(ActionEvent JavaDoc evt) {
61         ActionListener JavaDoc src = (ActionListener JavaDoc)ref.get();
62         if (src != null) {
63             src.actionPerformed(evt);
64
65         } else { // source listener was garbage collected
66 if (evt.getSource() instanceof Timer JavaDoc) {
67                 Timer JavaDoc timer = (Timer JavaDoc)evt.getSource();
68                 timer.removeActionListener(this);
69
70                 if (stopTimer) {
71                     timer.stop();
72                 }
73             }
74         }
75     }
76
77 }
78
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