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Java > Open Source Codes > org > mr > api > simple > Consumer


1 /*
2  * Copyright 2002 by
3  * <a HREF="http://www.coridan.com">Coridan</a>
4  * <a HREF="mailto: support@coridan.com ">support@coridan.com</a>
5  *
6  * The contents of this file are subject to the Mozilla Public License Version
7  * 1.1 (the "License"); you may not use this file except in compliance with the
8  * License. You may obtain a copy of the License at
9  * http://www.mozilla.org/MPL/
10  *
11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is "MantaRay" (TM).
17  *
18  * The Initial Developer of the Original Code is Uri Schneider.
19  * Portions created by the Initial Developer are Copyright (C) 2006
20  * Coridan Inc. All Rights Reserved.
21  *
22  * Contributor(s): all the names of the contributors are added in the source
23  * code where applicable.
24  *
25  * Alternatively, the contents of this file may be used under the terms of the
26  * LGPL license (the "GNU LESSER GENERAL PUBLIC LICENSE"), in which case the
27  * provisions of LGPL are applicable instead of those above. If you wish to
28  * allow use of your version of this file only under the terms of the LGPL
29  * License and not to allow others to use your version of this file under
30  * the MPL, indicate your decision by deleting the provisions above and
31  * replace them with the notice and other provisions required by the LGPL.
32  * If you do not delete the provisions above, a recipient may use your version
33  * of this file under either the MPL or the GNU LESSER GENERAL PUBLIC LICENSE.
34  
35  *
36  * This library is free software; you can redistribute it and/or modify it
37  * under the terms of the MPL as stated above or under the terms of the GNU
38  * Lesser General Public License as published by the Free Software Foundation;
39  * either version 2.1 of the License, or any later version.
40  *
41  * This library is distributed in the hope that it will be useful, but WITHOUT
42  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
43  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
44  * License for more details.
45  */

46 package org.mr.api.simple;
47
48 import org.mr.api.jms.MantaQueueConnectionFactory;
49
50 /**
51  * Consumer.java
52  *
53  * An object used to receive messages from a specific queue. Use the
54  * <code>SimpleAPI</code> factory to create one of these, and then simply use
55  * the {@link #receive receive} method to receive messages.<p>
56  * <b>Concurrency</b><p>
57  * This object is not safe for use by multiple concurrent threads. Lock it if
58  * want concurrency.
59  *
60  * Created: Thu Jun 24 19:43:25 2004
61  *
62  * @author Uri Schneider
63  * @version 1.0
64  * @see SimpleAPI
65  */

66 public class Consumer {
67     private String JavaDoc queueName;
68     private javax.jms.MessageConsumer JavaDoc consumer;
69
70     Consumer(String JavaDoc queueName) throws SimpleException {
71         this.queueName = queueName;
72
73         javax.jms.QueueConnectionFactory JavaDoc factory;
74         javax.jms.QueueConnection JavaDoc connection;
75         javax.jms.QueueSession JavaDoc session;
76         javax.jms.Queue JavaDoc queue;
77
78         try {
79             factory = new MantaQueueConnectionFactory();
80             connection = factory.createQueueConnection();
81             session = connection.createQueueSession(false, javax.jms.Session.
82                                                     AUTO_ACKNOWLEDGE);
83             queue = session.createQueue(queueName);
84             this.consumer = session.createConsumer(queue);
85             connection.start();
86         } catch (javax.jms.JMSException JavaDoc e) {
87             throw new SimpleException(e);
88         }
89     } // Consumer constructor
90

91     /**
92      * Receive a message synchronously from this consumer's queue.
93      * @return the message received, or null if a timeout occured.
94      * @throws SimpleException If this consumer is closed.
95      */

96     public Message receive() throws SimpleException {
97         if (this.consumer == null) {
98             throw new SimpleException(SimpleException.ERROR_CLOSED_ACTOR,
99                                       "consumer for queue " + this.queueName +
100                                       " is closed");
101         }
102         javax.jms.Message JavaDoc jmsMessage = null;
103         Message message = null;
104         try {
105             jmsMessage = this.consumer.receive();
106             if (jmsMessage != null) {
107                 message = new Message((javax.jms.BytesMessage JavaDoc) jmsMessage);
108             }
109         } catch (javax.jms.JMSException JavaDoc e) {
110             throw new SimpleException(e);
111         }
112
113         return message;
114     }
115
116     /**
117      * Close this consumer. All resources associated with this consumer are
118      * released, and no further operations are allowed.
119      *
120      * @throws SimpleException If this consumer was already closed.
121      */

122     public void close() throws SimpleException {
123         if (this.consumer == null) {
124             throw new SimpleException(SimpleException.ERROR_CLOSED_ACTOR,
125                                       "consumer for queue " + this.queueName +
126                                       " is already closed");
127         }
128
129         try {
130             this.consumer.close();
131             this.consumer = null;
132         } catch (javax.jms.JMSException JavaDoc e) {
133             throw new SimpleException(e);
134         }
135     }
136     /**
137      * @return Returns the queueName.
138      */

139     public String JavaDoc getQueueName() {
140         return queueName;
141     }
142 } // Consumer
143
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