javax.jms
Interface TopicSession

All Superinterfaces:
Runnable, Session
public interface TopicSession
extends Session

A TopicSession object provides methods for creating TopicPublisher, TopicSubscriber, and TemporaryTopic objects. It also provides a method for deleting its client's durable subscribers.

A TopicSession is used for creating Pub/Sub specific objects. In general, use the Session object, and use TopicSession only to support existing code. Using the Session object simplifies the programming model, and allows transactions to be used across the two messaging domains.

A TopicSession cannot be used to create objects specific to the point-to-point domain. The following methods inherit from Session, but must throw an IllegalStateException if used from TopicSession:

Version:
1.1 - April 9, 2002
Author:
Mark Hapner, Rich Burridge, Kate Stout
See Also:
Session, Connection.createSession(boolean, int), TopicConnection.createTopicSession(boolean, int), XATopicSession.getTopicSession()

Field Summary
 
Fields inherited from interface javax.jms.Session
AUTO_ACKNOWLEDGE, CLIENT_ACKNOWLEDGE, DUPS_OK_ACKNOWLEDGE, SESSION_TRANSACTED
 
Method Summary
 TopicSubscriber createDurableSubscriber(Topic topic, String name)
          Creates a durable subscriber to the specified topic.
 TopicSubscriber createDurableSubscriber(Topic topic, String name, String messageSelector, boolean noLocal)
          Creates a durable subscriber to the specified topic, using a message selector or specifying whether messages published by its own connection should be delivered to it.
 TopicPublisher createPublisher(Topic topic)
          Creates a publisher for the specified topic.
 TopicSubscriber createSubscriber(Topic topic)
          Creates a nondurable subscriber to the specified topic.
 TopicSubscriber createSubscriber(Topic topic, String messageSelector, boolean noLocal)
          Creates a nondurable subscriber to the specified topic, using a message selector or specifying whether messages published by its own connection should be delivered to it.
 TemporaryTopic createTemporaryTopic()
          Creates a TemporaryTopic object.
 Topic createTopic(String topicName)
          Creates a topic identity given a Topic name.
 void unsubscribe(String name)
          Unsubscribes a durable subscription that has been created by a client.
 
Methods inherited from interface javax.jms.Session
close, commit, createBrowser, createBrowser, createBytesMessage, createConsumer, createConsumer, createConsumer, createMapMessage, createMessage, createObjectMessage, createObjectMessage, createProducer, createQueue, createStreamMessage, createTemporaryQueue, createTextMessage, createTextMessage, getAcknowledgeMode, getMessageListener, getTransacted, recover, rollback, run, setMessageListener
 

Method Detail

createTopic

public Topic createTopic(String topicName)
                  throws JMSException
Creates a topic identity given a Topic name.

This facility is provided for the rare cases where clients need to dynamically manipulate topic identity. This allows the creation of a topic identity with a provider-specific name. Clients that depend on this ability are not portable.

Note that this method is not for creating the physical topic. The physical creation of topics is an administrative task and is not to be initiated by the JMS API. The one exception is the creation of temporary topics, which is accomplished with the createTemporaryTopic method.

Specified by:
createTopic in interface Session
Parameters:
topicName - the name of this Topic
Returns:
a Topic with the given name
Throws:
JMSException - if the session fails to create a topic due to some internal error.

createSubscriber

public TopicSubscriber createSubscriber(Topic topic)
                                 throws JMSException
Creates a nondurable subscriber to the specified topic.

A client uses a TopicSubscriber object to receive messages that have been published to a topic.

Regular TopicSubscriber objects are not durable. They receive only messages that are published while they are active.

In some cases, a connection may both publish and subscribe to a topic. The subscriber NoLocal attribute allows a subscriber to inhibit the delivery of messages published by its own connection. The default value for this attribute is false.

Parameters:
topic - the Topic to subscribe to
Throws:
JMSException - if the session fails to create a subscriber due to some internal error.
InvalidDestinationException - if an invalid topic is specified.

createSubscriber

public TopicSubscriber createSubscriber(Topic topic,
                                        String messageSelector,
                                        boolean noLocal)
                                 throws JMSException
Creates a nondurable subscriber to the specified topic, using a message selector or specifying whether messages published by its own connection should be delivered to it.

A client uses a TopicSubscriber object to receive messages that have been published to a topic.

Regular TopicSubscriber objects are not durable. They receive only messages that are published while they are active.

Messages filtered out by a subscriber's message selector will never be delivered to the subscriber. From the subscriber's perspective, they do not exist.

In some cases, a connection may both publish and subscribe to a topic. The subscriber NoLocal attribute allows a subscriber to inhibit the delivery of messages published by its own connection. The default value for this attribute is false.

Parameters:
topic - the Topic to subscribe to
messageSelector - only messages with properties matching the message selector expression are delivered. A value of null or an empty string indicates that there is no message selector for the message consumer.
noLocal - if set, inhibits the delivery of messages published by its own connection
Throws:
JMSException - if the session fails to create a subscriber due to some internal error.
InvalidDestinationException - if an invalid topic is specified.
InvalidSelectorException - if the message selector is invalid.

createDurableSubscriber

public TopicSubscriber createDurableSubscriber(Topic topic,
                                               String name)
                                        throws JMSException
Creates a durable subscriber to the specified topic.

If a client needs to receive all the messages published on a topic, including the ones published while the subscriber is inactive, it uses a durable TopicSubscriber. The JMS provider retains a record of this durable subscription and insures that all messages from the topic's publishers are retained until they are acknowledged by this durable subscriber or they have expired.

Sessions with durable subscribers must always provide the same client identifier. In addition, each client must specify a name that uniquely identifies (within client identifier) each durable subscription it creates. Only one session at a time can have a TopicSubscriber for a particular durable subscription.

A client can change an existing durable subscription by creating a durable TopicSubscriber with the same name and a new topic and/or message selector. Changing a durable subscriber is equivalent to unsubscribing (deleting) the old one and creating a new one.

In some cases, a connection may both publish and subscribe to a topic. The subscriber NoLocal attribute allows a subscriber to inhibit the delivery of messages published by its own connection. The default value for this attribute is false.

Specified by:
createDurableSubscriber in interface Session
Parameters:
topic - the non-temporary Topic to subscribe to
name - the name used to identify this subscription
Throws:
JMSException - if the session fails to create a subscriber due to some internal error.
InvalidDestinationException - if an invalid topic is specified.

createDurableSubscriber

public TopicSubscriber createDurableSubscriber(Topic topic,
                                               String name,
                                               String messageSelector,
                                               boolean noLocal)
                                        throws JMSException
Creates a durable subscriber to the specified topic, using a message selector or specifying whether messages published by its own connection should be delivered to it.

If a client needs to receive all the messages published on a topic, including the ones published while the subscriber is inactive, it uses a durable TopicSubscriber. The JMS provider retains a record of this durable subscription and insures that all messages from the topic's publishers are retained until they are acknowledged by this durable subscriber or they have expired.

Sessions with durable subscribers must always provide the same client identifier. In addition, each client must specify a name which uniquely identifies (within client identifier) each durable subscription it creates. Only one session at a time can have a TopicSubscriber for a particular durable subscription. An inactive durable subscriber is one that exists but does not currently have a message consumer associated with it.

A client can change an existing durable subscription by creating a durable TopicSubscriber with the same name and a new topic and/or message selector. Changing a durable subscriber is equivalent to unsubscribing (deleting) the old one and creating a new one.

Specified by:
createDurableSubscriber in interface Session
Parameters:
topic - the non-temporary Topic to subscribe to
name - the name used to identify this subscription
messageSelector - only messages with properties matching the message selector expression are delivered. A value of null or an empty string indicates that there is no message selector for the message consumer.
noLocal - if set, inhibits the delivery of messages published by its own connection
Throws:
JMSException - if the session fails to create a subscriber due to some internal error.
InvalidDestinationException - if an invalid topic is specified.
InvalidSelectorException - if the message selector is invalid.

createPublisher

public TopicPublisher createPublisher(Topic topic)
                               throws JMSException
Creates a publisher for the specified topic.

A client uses a TopicPublisher object to publish messages on a topic. Each time a client creates a TopicPublisher on a topic, it defines a new sequence of messages that have no ordering relationship with the messages it has previously sent.

Parameters:
topic - the Topic to publish to, or null if this is an unidentified producer
Throws:
JMSException - if the session fails to create a publisher due to some internal error.
InvalidDestinationException - if an invalid topic is specified.

createTemporaryTopic

public TemporaryTopic createTemporaryTopic()
                                    throws JMSException
Creates a TemporaryTopic object. Its lifetime will be that of the TopicConnection unless it is deleted earlier.

Specified by:
createTemporaryTopic in interface Session
Returns:
a temporary topic identity
Throws:
JMSException - if the session fails to create a temporary topic due to some internal error.

unsubscribe

public void unsubscribe(String name)
                 throws JMSException
Unsubscribes a durable subscription that has been created by a client.

This method deletes the state being maintained on behalf of the subscriber by its provider.

It is erroneous for a client to delete a durable subscription while there is an active TopicSubscriber for the subscription, or while a consumed message is part of a pending transaction or has not been acknowledged in the session.

Specified by:
unsubscribe in interface Session
Parameters:
name - the name used to identify this subscription
Throws:
JMSException - if the session fails to unsubscribe to the durable subscription due to some internal error.
InvalidDestinationException - if an invalid subscription name is specified.
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Copyright 2003 Sun Microsystems, Inc. All rights reserved.