ServiceAvailabilityBean


1   package jms.service;
2   
3   import javax.ejb.MessageDrivenBean  ;
4   import javax.ejb.MessageDrivenContext  ;
5   import javax.ejb.EJBException  ;
6   import javax.jms.*;
7   import javax.naming.NamingException  ;
8   import javax.naming.InitialContext  ;
9   
10  /**
11   * This is a simple MDB that processes a message containing an integer
12   * that represents a zip code, and returns a message containing a 
13   * boolean indicating whether DSL service is available at that zip code 
14   * or not.
15   * Internally the bean just returns true for zip codes < 50000 and
16   * false otherwise.
17   */
18  public class ServiceAvailabilityBean implements MessageDrivenBean  , MessageListener {
19      MessageDrivenContext   context = null;
20  
21      public void setMessageDrivenContext(MessageDrivenContext   context) {
22      this.context = context;
23      }
24      public void ejbCreate() throws EJBException   { }
25  
26      public void ejbRemove() {
27      context = null;
28      }
29  
30      public void onMessage(Message msg) {
31      try {
32          TextMessage  message = (TextMessage)msg;
33          // assume we have an integer
34          int zipCode = new Integer  (message.getText()).intValue();
35          // return true if zip code < 50000, false otherwise
36          if (zipCode<50000)
37          sendMessage(message,"true");
38          else
39          sendMessage(message,"false");
40      } catch(Exception   e) { 
41          // aargh - this should not happen usually
42          System.out.println(e); 
43          e.printStackTrace();
44      }
45      }
46  
47      public void sendMessage(TextMessage requestMsg, String   serviceAvailable) 
48      throws NamingException  , JMSException {
49      // wait for some time
50      InitialContext   jndiContext = new InitialContext  ();
51      QueueConnectionFactory factory = (QueueConnectionFactory)
52          jndiContext.lookup("ConnectionFactory");
53      QueueConnection connect = factory.createQueueConnection();
54      QueueSession session = connect.createQueueSession(false,Session.AUTO_ACKNOWLEDGE);
55      Queue queue = (Queue)requestMsg.getJMSReplyTo();
56      QueueSender sender = session.createSender(queue);
57      TextMessage message = session.createTextMessage();
58      // set the correlation ID
59      message.setJMSCorrelationID(requestMsg.getJMSMessageID());
60      // set the text
61      message.setText(serviceAvailable);
62      sender.send(message);
63      sender.close();
64      session.close();
65      connect.close();
66      }
67  }   
68  
69
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