1 /***
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
7 * statements and notices. Redistributions must also contain a
8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Exoffice Technologies. For written permission,
18 * please contact info@exolab.org.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Exoffice Technologies. Exolab is a registered
23 * trademark of Exoffice Technologies.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2001-2005 (C) Exoffice Technologies Inc. All Rights Reserved.
42 *
43 * $Id: QueueBrowserEndpoint.java,v 1.3 2005/08/30 07:26:49 tanderson Exp $
44 */
45 package org.exolab.jms.messagemgr;
46
47 import javax.jms.InvalidSelectorException;
48 import javax.jms.JMSException;
49
50 import org.exolab.jms.message.MessageImpl;
51
52
53 /***
54 * A QueueBrowserEndpoint is a QueueListener to a QueueDestinationCache. This
55 * enables it to receive all the messages, which it then feeds down to the
56 * client side.
57 *
58 * @author <a href="mailto:jima@comware.com.au">Jim Alateras</a>
59 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson
60 * @version $Revision: 1.3 $ $Date: 2005/08/30 07:26:49 $
61 */
62 public class QueueBrowserEndpoint extends AbstractConsumerEndpoint {
63
64 /***
65 * Cache of all handles for this consumer.
66 */
67 private MessageQueue _handles = new MessageQueue();
68
69 /***
70 * The destination that this consumer subscribes to.
71 */
72 private QueueDestinationCache _cache;
73
74
75 /***
76 * Create a new <code>QueueBrowserEndpoint</code>.
77 *
78 * @param consumerId the identity of this consumer
79 * @param cache the destination cache
80 * @param selector the message selector. May be <code>null</code>
81 * @throws InvalidSelectorException if <code>selector</code> is invalid
82 * @throws JMSException if the destination cache can't be
83 * created
84 */
85 public QueueBrowserEndpoint(long consumerId, QueueDestinationCache cache,
86 String selector)
87 throws InvalidSelectorException, JMSException {
88 super(consumerId, cache.getDestination(), selector, false);
89
90 _cache = cache;
91
92
93
94 _cache.addQueueListener(this);
95 _cache.playbackMessages(this);
96 }
97
98 /***
99 * This event is called when a non-persistent message is added to a
100 * <code>DestinationCache</code>..
101 *
102 * @param handle a handle to the added message
103 * @param message the added message
104 * @return <code>true</code> if the listener accepted the message; otherwise
105 * <code>false</ode>
106 */
107 public boolean messageAdded(MessageHandle handle, MessageImpl message) {
108 _handles.add(handle);
109
110
111 notifyMessageAvailable();
112 return true;
113 }
114
115 /***
116 * This event is called when a persistent message is added to the
117 * <code>DestinationCache</code>.
118 *
119 * @param handle a handle to the added message
120 * @param message the added message
121 * @return <code>true</code>
122 */
123 public boolean persistentMessageAdded(MessageHandle handle,
124 MessageImpl message) {
125 return messageAdded(handle, message);
126 }
127
128 /***
129 * This event is called when a message is removed from the
130 * <code>DestinationCache</code>.
131 *
132 * @param messageId the identifier of the removed message
133 */
134 public void messageRemoved(String messageId) {
135 _handles.remove(messageId);
136 }
137
138 /***
139 * This event is called when a message is removed from the
140 * <code>DestinationCache</code>.
141 *
142 * @param messageId a handle to the removed message
143 */
144 public void persistentMessageRemoved(String messageId) {
145 messageRemoved(messageId);
146 }
147
148 /***
149 * Return the number of unsent messages in the cache for this consumer.
150 *
151 * @return the number of unsent messages
152 */
153 public int getMessageCount() {
154 return _handles.size();
155 }
156
157 /***
158 * Return the next available message to the client.
159 *
160 * @param cancel
161 * @return the next message, or <code>null</code> if none is available
162 * @throws JMSException for any error
163 */
164 protected MessageHandle doReceive(Condition cancel) throws JMSException {
165 MessageHandle result = null;
166 MessageHandle handle;
167 while (!cancel.get() && (handle = _handles.removeFirst()) != null) {
168
169 MessageImpl message = handle.getMessage();
170 if (message != null) {
171 if (selects(message)) {
172 result = handle;
173
174 break;
175 }
176 }
177 }
178 return result;
179 }
180
181 /***
182 * Closes this endpoint.
183 */
184 protected void doClose() {
185
186 _cache.removeQueueListener(this);
187 }
188
189 }