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1 /*
2 * Copyright (c) 2003 Scott Howlett & Paul Libbrecht.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 *
17 * 3. The end-user documentation included with the redistribution,
18 * if any, must include the following acknowledgment:
19 * "This product includes software developed by the Xwing
20 * Project ( http://xwing.sourceforge.net/ )."
21 * Alternately, this acknowledgment may appear in the software itself,
22 * if and wherever such third-party acknowledgments normally appear.
23 *
24 * 4. The name "Xwing" must not be used to endorse or promote products
25 * derived from this software without prior written permission. For
26 * written permission, please contact the project authors via
27 * the Xwing project site, http://xwing.sourceforge.net/ .
28 *
29 * 5. Products derived from this software may not be called "Xwing",
30 * nor may "Xwing" appear in their name, without prior written
31 * permission of the Xwing project.
32 *
33 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
34 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
36 * DISCLAIMED. IN NO EVENT SHALL THE XWING AUTHORS OR THE PROJECT
37 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
38 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
40 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
41 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
42 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
43 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 *
46 * For more information on Xwing, please see
47 * < http://xwing.sourceforge.net/ >.
48 */
49
50 package net.sourceforge.xwing;
51
52 import javax.swing.event.ChangeEvent;
53 import javax.swing.event.ChangeListener;
54
55 /***
56 * A partial implementation of SourceSink that takes care of managing
57 * the list of listeners. Derived classes must still implement
58 * get() and set().
59 *
60 * @author Scott Howlett
61 * @version $Revision: 1.2 $
62 */
63 public abstract class AbstractSourceSink implements SourceSink {
64
65 private static final ChangeListener[] NULL_ARRAY = new ChangeListener[0];
66 private ChangeListener[] listeners = NULL_ARRAY;
67
68 public synchronized void addChangeListener(ChangeListener l) {
69 if (listeners == NULL_ARRAY) {
70 listeners = new ChangeListener[] {
71 l
72 };
73 } else {
74 int len = listeners.length;
75 ChangeListener[] tmp = new ChangeListener[len + 1];
76 System.arraycopy(listeners, 0, tmp, 0, len);
77 tmp[len] = l;
78 listeners = tmp;
79 }
80 }
81
82 public synchronized void removeChangeListener(ChangeListener l) {
83 int len = listeners.length;
84 for (int i = len - 1; i >= 0; --i) {
85 if (listeners[i] == l) {
86 if (len == 1) {
87 listeners = NULL_ARRAY;
88 } else {
89 ChangeListener[] tmp = new ChangeListener[--len];
90
91 if (i > 0) {
92 System.arraycopy(listeners, 0, tmp, 0, i);
93 }
94
95 if (i < len) {
96 System.arraycopy(listeners, i + 1, tmp, i, len - i);
97 }
98 listeners = tmp;
99 }
100 break;
101 }
102 }
103 }
104
105 /***
106 * Calls the stateChanged method of all registered listeners.
107 * Derived classes should call this method whenever they
108 * change the internal state.
109 */
110
111 protected void fireStateChanged() {
112 ChangeListener[] tmp = listeners;
113 int len = tmp.length;
114 ChangeEvent ev = len == 0 ? null : new ChangeEvent(this);
115
116 for (int i = 0; i < tmp.length; ++i) {
117 tmp[i].stateChanged(ev);
118 }
119 }
120 }
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