A client uses a TopicPublisher object to publish messages on a
topic. A TopicPublisher object is the publish-subscribe form
of a message producer.
Normally, the Topic is specified when a
TopicPublisher is created. In this case, an attempt to use
the publish methods for an unidentified
TopicPublisher will throw a
java.lang.UnsupportedOperationException.
If the TopicPublisher is created with an unidentified
Topic, an attempt to use the publish methods that
assume that the Topic has been identified will throw a
java.lang.UnsupportedOperationException.
During the execution of its publish method,
a message must not be changed by other threads within the client.
If the message is modified, the result of the publish is
undefined.
After publishing a message, a client may retain and modify it
without affecting the message that has been published. The same message
object may be published multiple times.
The following message headers are set as part of publishing a
message: JMSDestination, JMSDeliveryMode,
JMSExpiration, JMSPriority,
JMSMessageID and JMSTimeStamp.
When the message is published, the values of these headers are ignored.
After completion of the publish, the headers hold the values
specified by the method publishing the message. It is possible for the
publish method not to set JMSMessageID and
JMSTimeStamp if the
setting of these headers is explicitly disabled by the
MessageProducer.setDisableMessageID or
MessageProducer.setDisableMessageTimestamp method.
Creating a MessageProducer provides the same features as
creating a TopicPublisher. A MessageProducer object is
recommended when creating new code. The TopicPublisher is
provided to support existing code.
Because TopicPublisher inherits from
MessageProducer, it inherits the
send methods that are a part of the MessageProducer
interface. Using the send methods will have the same
effect as using the
publish methods: they are functionally the same. | 