01 /*
02 * Copyright 2000-2004 Sun Microsystems, Inc. All Rights Reserved.
03 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04 *
05 * This code is free software; you can redistribute it and/or modify it
06 * under the terms of the GNU General Public License version 2 only, as
07 * published by the Free Software Foundation. Sun designates this
08 * particular file as subject to the "Classpath" exception as provided
09 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.util;
27
28 /**
29 * An abstract wrapper class for an EventListener class which associates a set
30 * of additional parameters with the listener. Subclasses must provide the
31 * storage and accessor methods for the additional arguments or parameters.
32 *
33 * Subclasses of EventListenerProxy may be returned by getListeners() methods
34 * as a way of associating named properties with their listeners.
35 *
36 * For example, a Bean which supports named properties would have a two
37 * argument method signature for adding a PropertyChangeListener for a
38 * property:
39 *
40 * public void addPropertyChangeListener(String propertyName,
41 * PropertyChangeListener listener);
42 *
43 * If the Bean also implemented the zero argument get listener method:
44 *
45 * public PropertyChangeListener[] getPropertyChangeListeners();
46 *
47 * then the array may contain inner PropertyChangeListeners which are also
48 * PropertyChangeListenerProxy objects.
49 *
50 * If the calling method is interested in retrieving the named property then it
51 * would have to test the element to see if it is a proxy class.
52 *
53 * @since 1.4
54 */
55 public abstract class EventListenerProxy implements EventListener {
56 private final EventListener listener;
57
58 /**
59 * @param listener The listener object.
60 */
61 public EventListenerProxy(EventListener listener) {
62 this .listener = listener;
63 }
64
65 /**
66 * @return The listener associated with this proxy.
67 */
68 public EventListener getListener() {
69 return listener;
70 }
71 }
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