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Java > Open Source Codes > org > ungoverned > oscar > util > Dispatcher


1 /*
2  * Oscar - An implementation of the OSGi framework.
3  * Copyright (c) 2004, Richard S. Hall
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * * Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  * * 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  * * Neither the name of the ungoverned.org nor the names of its
17  * contributors may be used to endorse or promote products derived
18  * from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  *
32  * Contact: Richard S. Hall (heavy@ungoverned.org)
33  * Contributor(s):
34  *
35 **/
36 package org.ungoverned.oscar.util;
37
38 import java.util.EventListener JavaDoc;
39 import java.util.EventObject JavaDoc;
40
41 /**
42  * This interface is used by <tt>DispatchQueue</tt> to dispatch events.
43  * Generally speaking, each type of event to dispatch will have an instance
44  * of a <tt>Dispatcher</tt> so that the dispatch queue can dispatch to
45  * the appropriate listener method for the specific listener type,
46  * for example:
47  * <pre>
48  * Dispatcher d = new Dispatcher() {
49  * public void dispatch(EventListener l, EventObject eventObj)
50  * {
51  * ((FooListener) l).fooXXX((FooEvent) eventObj);
52  * }
53  * };
54  * FooEvent event = new FooEvent(this);
55  * dispatchQueue.dispatch(d, FooListener.class, event);
56  * </pre>
57  * In the above code substitute a specific listener and event for the
58  * <tt>Foo</tt> listener and event. <tt>Dispatcher</tt>s can be reused, so
59  * it is a good idea to cache them to avoid unnecessary memory allocations.
60 **/
61 public interface Dispatcher
62 {
63     /**
64      * Dispatch an event to a specified event listener.
65      *
66      * @param l the event listener to receive the event.
67      * @param eventObj the event to dispatch.
68     **/
69     public void dispatch(EventListener JavaDoc l, EventObject JavaDoc eventObj);
70 }
71
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