QueueRequestor


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9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
10   * See the License for the specific language governing 
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13   * When distributing Covered Code, include this CDDL 
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15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
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20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  
24  
25  package javax.jms;
26  
27  /** The <CODE>QueueRequestor</CODE> helper class simplifies
28    * making service requests.
29    *
30    * <P>The <CODE>QueueRequestor</CODE> constructor is given a non-transacted 
31    * <CODE>QueueSession</CODE> and a destination <CODE>Queue</CODE>. It creates a
32    * <CODE>TemporaryQueue</CODE> for the responses and provides a 
33    * <CODE>request</CODE> method that sends the request message and waits 
34    * for its reply.
35    *
36    * <P>This is a basic request/reply abstraction that should be sufficient 
37    * for most uses. JMS providers and clients are free to create more 
38    * sophisticated versions.
39    *
40    * @version     1.0 - 8 July 1998
41    * @author      Mark Hapner
42    * @author      Rich Burridge
43    *
44    * @see         javax.jms.TopicRequestor
45    */
46  
47  public class QueueRequestor {
48  
49      QueueSession     session;     // The queue session the queue belongs to.
50      Queue            queue;       // The queue to perform the request/reply on.
51      TemporaryQueue   tempQueue;
52      QueueSender      sender;
53      QueueReceiver    receiver;
54  
55  
56      /** Constructor for the <CODE>QueueRequestor</CODE> class.
57        *  
58        * <P>This implementation assumes the session parameter to be non-transacted,
59        * with a delivery mode of either <CODE>AUTO_ACKNOWLEDGE</CODE> or 
60        * <CODE>DUPS_OK_ACKNOWLEDGE</CODE>.
61        *
62        * @param session the <CODE>QueueSession</CODE> the queue belongs to
63        * @param queue the queue to perform the request/reply call on
64        *  
65        * @exception JMSException if the JMS provider fails to create the
66        *                         <CODE>QueueRequestor</CODE> due to some internal
67        *                         error.
68        * @exception InvalidDestinationException if an invalid queue is specified.
69        */ 
70  
71      public
72      QueueRequestor(QueueSession   session, Queue   queue) throws JMSException   {
73          this.session = session;
74          this.queue   = queue;
75          tempQueue    = session.createTemporaryQueue();
76          sender       = session.createSender(queue);
77          receiver     = session.createReceiver(tempQueue);
78      }
79  
80  
81      /** Sends a request and waits for a reply. The temporary queue is used for
82        * the <CODE>JMSReplyTo</CODE> destination, and only one reply per request 
83        * is expected.
84        *  
85        * @param message the message to send
86        *  
87        * @return the reply message
88        *  
89        * @exception JMSException if the JMS provider fails to complete the
90        *                         request due to some internal error.
91        */
92  
93      public Message  
94      request(Message   message) throws JMSException   {
95      message.setJMSReplyTo(tempQueue);
96      sender.send(message);
97      return (receiver.receive());
98      }
99  
100 
101     /** Closes the <CODE>QueueRequestor</CODE> and its session.
102       *
103       * <P>Since a provider may allocate some resources on behalf of a 
104       * <CODE>QueueRequestor</CODE> outside the Java virtual machine, clients 
105       * should close them when they 
106       * are not needed. Relying on garbage collection to eventually reclaim 
107       * these resources may not be timely enough.
108       *  
109       * <P>Note that this method closes the <CODE>QueueSession</CODE> object 
110       * passed to the <CODE>QueueRequestor</CODE> constructor.
111       *
112       * @exception JMSException if the JMS provider fails to close the
113       *                         <CODE>QueueRequestor</CODE> due to some internal
114       *                         error.
115       */
116 
117     public void
118     close() throws JMSException   {
119 
120     // publisher and consumer created by constructor are implicitly closed.
121     session.close();
122         tempQueue.delete();
123     }
124 }
125
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