Sun Java System Messaging Server 6.3 Administration Guide

22.1.3 Benefits of Using JMQ Notification

The JMQ notification plug-in, with Message Queue, provides the following benefits: Publishing to a Topic or a Queue

A topic and queue use different messaging delivery patterns; each one can be configured in a Message Queue service.

Topic. When a message producer sends a message to a topic, a publish/subscribe architecture is used. In this broadcast pattern, a producer sends a message to a topic destination. Any number of consumers can be subscribed to this topic destination. Each consumer subscribed to the topic gets its own copy of the message. If no consumers are subscribed to the topic, the message is discarded.

The Event Notification Service also uses a publish/subscribe architecture; it is similar to the topic pattern defined in Message Queue.

Queue. When a message producer sends a message to a queue, a point-to-point architecture is used. In this pattern, a producer sends a message to a queue destination from which only one consumer can receive it. If several consumers are waiting for messages from the queue, only one subscriber will receive the message. If no consumers are waiting, the message is held until either the message times out, or a consumer expresses an interest in the queue.

Producing messages to a queue allows you to spread the message load across multiple consumers. Using Multiple JMQ Notification Plug-ins

You can configure from one to five notification plug-ins.

Messaging Server provides a plug-in library at the following default location:


You use the configutil utility to specify parameters for a plug-in and to point the plug-in to the library of executable code.

If you specify more than one plug-in, each plug-in produces notification messages independently of the others. For example, if two plug-ins are configured with a delete-message parameter, and a message is deleted from a user's mailbox, both plug-ins will produce a notification message.

By configuring multiple plug-ins, you can take advantage of different message-distribution patterns for different purposes. For example, you could configure three different plug-ins to produce messages Configuring Parameters for a Notification Plug-in

For each plug-in you configure, you must define a separate set of configutil parameters.

The parameters determine two kinds of information:

For instructions on how to configure a plug-in, see To Configure a JMQ Notification Plug-in.