1 /*
2 * Copyright (C) The Apache Software Foundation. All rights reserved.
3 *
4 * This software is published under the terms of the Apache Software License
5 * version 1.1, a copy of which has been included with this distribution in
6 * the LICENSE file.
7 *
8 * $Id: DefaultServerSessionPool.java 155459 2005-02-26 13:24:44Z dirkv $
9 */
10 package org.apache.commons.messenger;
11
12 import java.util.LinkedList;
13
14 import javax.jms.JMSException;
15 import javax.jms.Message;
16 import javax.jms.MessageListener;
17 import javax.jms.ServerSession;
18 import javax.jms.ServerSessionPool;
19 import javax.jms.Session;
20
21
22 /** <p><code>DefaultServerSessionPool</code> is a default implementation of
23 * the JMS ServerSessionPool interface.</p>
24 *
25 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
26 * @version $Revision: 155459 $
27 */
28 public class DefaultServerSessionPool implements ServerSessionPool {
29
30 /** the list of ServerSession objects */
31 private LinkedList list = new LinkedList();
32 /** the factory used to create new Sessions */
33 private SessionFactory sessionFactory;
34 /** The MessageListener which are fired by new JMS Sessions */
35 private MessageListener listener;
36 /** maximum blocking time, just in case a notify goes walkies */
37 private long timeout = 5000;
38
39 public DefaultServerSessionPool() {
40 }
41
42 public DefaultServerSessionPool(SessionFactory sessionFactory, MessageListener listener, int numberOfServerSessions) throws JMSException {
43 this.sessionFactory = sessionFactory;
44 this.listener = listener;
45
46 for ( int i = 0; i < numberOfServerSessions; i++ ) {
47 list.add( createServerSession() );
48 }
49 }
50
51
52 /** Return a server session from the pool.
53 *
54 * @return a server session from the pool.
55 *
56 * @exception JMSException if a JMS error occurs.
57 */
58 public synchronized ServerSession getServerSession() throws JMSException {
59 // we may want to grow if there are no sessions available
60 while (list.isEmpty() ) {
61 try {
62 wait( timeout );
63 }
64 catch(InterruptedException ex) {
65 // ignore
66 }
67 }
68 return (ServerSession) list.removeFirst();
69 }
70
71 public synchronized void putServerSession(ServerSession serverSession) {
72 list.addLast(serverSession);
73 notify();
74 }
75
76 // Implementation methods
77 //-------------------------------------------------------------------------
78 protected ServerSession createServerSession() throws JMSException {
79 Session session = sessionFactory.createSession();
80 final DefaultServerSession serverSession = new DefaultServerSession(session);
81 session.setMessageListener(
82 new MessageListener() {
83 public void onMessage(Message message) {
84 try {
85 listener.onMessage(message);
86 }
87 finally {
88 // now give this session back to the pool
89 putServerSession( serverSession );
90 }
91 }
92 }
93 );
94 return serverSession;
95 }
96 }
97