O'Reilly - Java Message Service

Java Message Service
Appendix D.) Therefore, durable subscriptions must be identified by their own name;
simply using the topic name and the client ID will not suffice.
Figure 4.2. Managing active durable subscriptions
The JMS specification is intentionally vague about how the JMS provider determines the
uniqueness of a client ID. Various provider implementations are allowed to have their own
internal rules for what constitutes a unique client. The setClientID( ) method on the
connection object is provided in the API as a hint. The client ID is set in the constructor of
our Retailer example:
public Retailer( String broker, String username, String password){
try {
....
connect = factory.createTopicConnection (username, password);
connect.setClientID(username);
....
}
....
}
4.4 Publishing the Message Persistently
Both the Wholesaler and Retailer classes publish messages using the persistent delivery
mode:
publisher.publish(
message,
javax.jms.DeliveryMode.PERSISTENT,
javax.jms.Message.DEFAULT_PRIORITY,
1800000);
Note the use of the overloaded publish( ) method, with parameters that specify delivery
mode, priority, and message expiration. This method provides an alternative to using the
Message.setJMSDeliveryMode( ) and TopicPublisher.setTimeToLive( ) operations, as
discussed in Chapter 3. In JMS, the delivery mode (persistent, nonpersistent) is a Quality
of Service (QoS) setting on the message itself. Marking the message as persistent ensures
that the message will be saved to a reliable persistent store by the JMS provider before the
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