O'Reilly - Java Message Service

Java Message Service
The JMSDeliveryMode can be obtained from the Message object using the
getJMSDeliveryMode( ) method:
public void onMessage(Message message){
try {
if (message.getJMSDeliveryMode( ) == DeliveryMode.PERSISTENT){
// Do something
} else {
// Do something else
}
} catch (JMSException jmse){jmse.printStackTrace( );}
}
JMSMessageID Purpose: Routing
The JMSMessageID is a String value that uniquely identifies a message. How unique the
identifier is depends on the vendor. It may only be unique for that installation of the
message server, or it may be universally unique.
The JMSMessageID can be useful for historical repositories in applications where messages
need to be uniquely indexed. The JMSMessageID is also useful for correlating messages,
which is done using the JMSCorrelationID header.
The message provider generates the JMSMessageID automatically when the message is
received from a JMS client. The JMSMessageID must start with ID:, but the rest of
JMSMessageID can be any collection of characters that uniquely identifies the message to
the JMS provider. Here is an example of a JMSMessageID generated by Progress' SonicMQ:
// JMSMessageID generated by SonicMQ
ID:6c867f96:20001:DF59525514
If a unique message ID is not needed by the JMS application, the JMS client can provide a
hint to the message server that an ID is not necessary by using the setDisableMessageID( )
method (as shown in the following code). Vendors that heed this hint can reduce message
processing time by not generating unique IDs for each message. If a JMSMessageID is not
generated, the getJMSMessageID( ) method returns null:
// Publish-and-subscribe
TopicPublisher topicPublisher = topicSession.createPublisher(topic);
topicPublisher.setDisableMessageID(true);
// Point-to-point
QueueSender queueSender = queueSession.createSender(topic);
queueSender.setDisableMessageID(true);
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