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.
@see Session#createProducer(Destination)
@see TopicSession#createPublisher(Topic)
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