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TopicRequestor.javaAPI DocGlassfish v2 API5573Fri May 04 22:36:16 BST 2007javax.jms

TopicRequestor

public class TopicRequestor extends Object
The TopicRequestor helper class simplifies making service requests.

The TopicRequestor constructor is given a non-transacted TopicSession and a destination Topic. It creates a TemporaryTopic for the responses and provides a request method that sends the request message and waits for its reply.

This is a basic request/reply abstraction that should be sufficient for most uses. JMS providers and clients are free to create more sophisticated versions.

version
1.0 - 8 July 1998
author
Mark Hapner
author
Rich Burridge
see
javax.jms.QueueRequestor

Fields Summary
TopicSession
session
Topic
topic
TemporaryTopic
tempTopic
TopicPublisher
publisher
TopicSubscriber
subscriber
Constructors Summary
public TopicRequestor(TopicSession session, Topic topic)
Constructor for the TopicRequestor class.

This implementation assumes the session parameter to be non-transacted, with a delivery mode of either AUTO_ACKNOWLEDGE or DUPS_OK_ACKNOWLEDGE.

param
session the TopicSession the topic belongs to
param
topic the topic to perform the request/reply call on
exception
JMSException if the JMS provider fails to create the TopicRequestor due to some internal error.
exception
InvalidDestinationException if an invalid topic is specified.

	this.session = session;
	this.topic   = topic;
        tempTopic    = session.createTemporaryTopic();
        publisher    = session.createPublisher(topic);
        subscriber   = session.createSubscriber(tempTopic);
Methods Summary
public voidclose()
Closes the TopicRequestor and its session.

Since a provider may allocate some resources on behalf of a TopicRequestor outside the Java virtual machine, clients should close them when they are not needed. Relying on garbage collection to eventually reclaim these resources may not be timely enough.

Note that this method closes the TopicSession object passed to the TopicRequestor constructor.

exception
JMSException if the JMS provider fails to close the TopicRequestor due to some internal error.


	// publisher and consumer created by constructor are implicitly closed.
	session.close();
	tempTopic.delete();
public Messagerequest(Message message)
Sends a request and waits for a reply. The temporary topic is used for the JMSReplyTo destination; the first reply is returned, and any following replies are discarded.

param
message the message to send
return
the reply message
exception
JMSException if the JMS provider fails to complete the request due to some internal error.

	message.setJMSReplyTo(tempTopic);
        publisher.publish(message);
	return(subscriber.receive());