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1   /*** 
2    * 
3    * Copyright 2004 Protique Ltd
4    * 
5    * Licensed under the Apache License, Version 2.0 (the "License"); 
6    * you may not use this file except in compliance with the License. 
7    * You may obtain a copy of the License at 
8    * 
9    * http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS, 
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
14   * See the License for the specific language governing permissions and 
15   * limitations under the License. 
16   * 
17   **/
18  
19  package org.codehaus.activemq;
20  
21  import org.apache.commons.logging.Log;
22  import org.apache.commons.logging.LogFactory;
23  import org.codehaus.activemq.message.ActiveMQMessage;
24  import org.codehaus.activemq.message.util.MemoryBoundedQueue;
25  
26  import javax.jms.JMSException;
27  import java.util.Iterator;
28  
29  /***
30   * A utility class used by the Sessionfor dispatching messages asycnronously to consumers
31   *
32   * @version $Revision: 1.3 $
33   * @see javax.jms.Session
34   */
35  class ActiveMQSessionExecutor implements Runnable {
36      private static final Log log = LogFactory.getLog(ActiveMQSessionExecutor.class);
37      private ActiveMQSession session;
38      private MemoryBoundedQueue messageQueue;
39      private boolean closed;
40      private Thread runner;
41      private boolean doDispatch;
42  
43      ActiveMQSessionExecutor(ActiveMQSession session, MemoryBoundedQueue queue) {
44          this.session = session;
45          this.messageQueue = queue;
46          this.doDispatch = true;
47      }
48  
49      void setDoDispatch(boolean value) {
50          doDispatch = value;
51      }
52  
53      void execute(ActiveMQMessage message) {
54          messageQueue.enqueue(message);
55      }
56  
57      void executeFirst(ActiveMQMessage message) {
58          messageQueue.enqueueFirstNoBlock(message);
59      }
60  
61      /***
62       * implementation of Runnable
63       */
64      public void run() {
65          while (!closed && doDispatch) {
66              ActiveMQMessage message = null;
67              try {
68                  message = (ActiveMQMessage) messageQueue.dequeue(100);
69              }
70              catch (InterruptedException ie) {
71              }
72              if (!closed) {
73                  if (message != null) {
74                      if (doDispatch) {
75                          for (Iterator i = this.session.consumers.iterator(); i.hasNext();) {
76                              ActiveMQMessageConsumer consumer = (ActiveMQMessageConsumer) i.next();
77                              if (message.isConsumerTarget(consumer.getConsumerNumber())) {
78                                  try {
79                                      consumer.processMessage(message.shallowCopy());
80                                  }
81                                  catch (JMSException e) {
82                                      this.session.connection.handleAsyncException(e);
83                                  }
84                              }
85                          }
86                      }
87                      else {
88                          messageQueue.enqueueFirstNoBlock(message);
89                      }
90                  }
91              }
92          }
93      }
94  
95      synchronized void start() {
96          messageQueue.start();
97          if (runner == null && doDispatch) {
98              runner = new Thread(this, "JmsSessionDispather: " + session.getSessionId());
99              runner.setPriority(Thread.MAX_PRIORITY);
100             //runner.setDaemon(true);
101             runner.start();
102         }
103     }
104 
105     synchronized void stop() {
106         messageQueue.stop();
107     }
108 
109     synchronized void close() {
110         closed = true;
111         messageQueue.close();
112     }
113 
114     void clear() {
115         messageQueue.clear();
116     }
117 
118     ActiveMQMessage dequeueNoWait() {
119         try {
120             return (ActiveMQMessage) messageQueue.dequeueNoWait();
121         }
122         catch (InterruptedException ie) {
123             return null;
124         }
125     }
126     
127     protected void clearMessagesInProgress(){
128         messageQueue.clear();
129     }
130 }