Introduction

 

With publish/subscribe messaging, one message producer can send messages to many message consumers at one time. The message producer need know nothing about the consumers receiving its messages, it needs to know only about the common destination. Similarly, the message consumers need to know only about the common destination. This common destination is called a topic.

A message producer that sends messages to a topic is a publisher and a message consumer that receives messages from a topic is a subscriber.

A message consumer receives messages on all topics to which it has subscribed. All messages sent to a topic are forwarded to all the message consumers subscribed to that topic at that time. Each consumer receives its own copy of each message.

JMS clients can establish durable subscriptions that allow consumers to disconnect and later reconnect and collect messages published while they were disconnected.

The connection between messages issued by publishers and the subscribers is made, in WebSphere MQ, by the publish/subscribe broker. The broker (sometimes referred to as the message broker) has a record of all the subscribers registered to a topic. When a message is published to a topic, the broker manages the forwarding of that message to the topic's subscribers.

To run a WebSphere MQ JMS publish/subscribe application, be able to connect to a message broker.

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