001: /*
002:
003: ============================================================================
004: The Apache Software License, Version 1.1
005: ============================================================================
006:
007: Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
008:
009: Redistribution and use in source and binary forms, with or without modifica-
010: tion, are permitted provided that the following conditions are met:
011:
012: 1. Redistributions of source code must retain the above copyright notice,
013: this list of conditions and the following disclaimer.
014:
015: 2. Redistributions in binary form must reproduce the above copyright notice,
016: this list of conditions and the following disclaimer in the documentation
017: and/or other materials provided with the distribution.
018:
019: 3. The end-user documentation included with the redistribution, if any, must
020: include the following acknowledgment: "This product includes software
021: developed by the Apache Software Foundation (http://www.apache.org/)."
022: Alternately, this acknowledgment may appear in the software itself, if
023: and wherever such third-party acknowledgments normally appear.
024:
025: 4. The names "Batik" and "Apache Software Foundation" must not be
026: used to endorse or promote products derived from this software without
027: prior written permission. For written permission, please contact
028: apache@apache.org.
029:
030: 5. Products derived from this software may not be called "Apache", nor may
031: "Apache" appear in their name, without prior written permission of the
032: Apache Software Foundation.
033:
034: THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
035: INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
036: FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
037: APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
038: INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
039: DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
040: OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
041: ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
042: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
043: THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
044:
045: This software consists of voluntary contributions made by many individuals
046: on behalf of the Apache Software Foundation. For more information on the
047: Apache Software Foundation, please see <http://www.apache.org/>.
048:
049: */
050:
051: package org.apache.batik.util;
052:
053: import java.awt.EventQueue;
054: import java.util.List;
055: import java.lang.reflect.InvocationTargetException;
056:
057: /**
058: * Generic class to dispatch events in a highly relyable way
059: *
060: * @author <a href="mailto:deweese@apache.org>l449433</a>
061: * @version $Id$
062: */
063: public class EventDispatcher {
064:
065: public interface Dispatcher {
066: public void dispatch(Object listener, Object event);
067: }
068:
069: public static void fireEvent(final Dispatcher dispatcher,
070: final List listeners, final Object evt,
071: final boolean useEventQueue) {
072: if (useEventQueue && !EventQueue.isDispatchThread()) {
073: Runnable r = new Runnable() {
074: public void run() {
075: fireEvent(dispatcher, listeners, evt, useEventQueue);
076: }
077: };
078: try {
079: EventQueue.invokeAndWait(r);
080: } catch (InvocationTargetException e) {
081: e.printStackTrace();
082: } catch (InterruptedException e) {
083: // Assume they will get delivered????
084: // be nice to wait on List but how???
085: } catch (ThreadDeath td) {
086: throw td;
087: } catch (Throwable t) {
088: t.printStackTrace();
089: }
090: return;
091: }
092:
093: Object[] ll = null;
094: Throwable err = null;
095: int retryCount = 10;
096: while (--retryCount != 0) {
097: // If the thread has been interrupted this can 'mess up'
098: // the class loader and cause this otherwise safe code to
099: // throw errors.
100: try {
101: synchronized (listeners) {
102: if (listeners.size() == 0)
103: return;
104: ll = listeners.toArray();
105: break;
106: }
107: } catch (Throwable t) {
108: err = t;
109: }
110: }
111: if (ll == null) {
112: if (err != null)
113: err.printStackTrace();
114: return;
115: }
116: dispatchEvent(dispatcher, ll, evt);
117: }
118:
119: protected static void dispatchEvent(final Dispatcher dispatcher,
120: final Object[] ll, final Object evt) {
121: ThreadDeath td = null;
122: try {
123: for (int i = 0; i < ll.length; i++) {
124: try {
125: Object l;
126: synchronized (ll) {
127: l = ll[i];
128: if (l == null)
129: continue;
130: ll[i] = null;
131: }
132: dispatcher.dispatch(l, evt);
133: } catch (ThreadDeath t) {
134: // Keep delivering messages but remember to throw later.
135: td = t;
136: } catch (Throwable t) {
137: t.printStackTrace();
138: }
139: }
140: } catch (ThreadDeath t) {
141: // Remember to throw later.
142: td = t;
143: } catch (Throwable t) {
144: if (ll[ll.length - 1] != null)
145: dispatchEvent(dispatcher, ll, evt);
146: t.printStackTrace();
147: }
148: if (td != null)
149: throw td;
150: }
151: }
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