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:

• createBrowser
• createQueue
• createTemporaryQueue

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

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

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

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

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

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

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

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

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.