JMS Messaging Styles

Technologies / Informatique

A messaging style refers to how messages are produced and consumed. JMS supports the publish-subscribe (pub-sub) and point-to-point (PTP) messaging styles.

Point-to-point (PTP) Messaging (Queu)

In point-to-point (PTP) messaging, message producers and consumers are known as senders and receivers.

The central concept in PTP messaging is a destination called a queue. A queue represents a single receiver. Message senders submit messages to a specific queue and another client receives the messages from the queue.

In the PTP model, a queue may receive messages from many different senders and may deliver messages to multiple receivers; however each message is delivered to only one receiver.

Publish-Subscribe Messaging (Topic)

In publish-subscribe messaging, message producers and consumers are known as publishers and subscribers.

The central concept in the publish-subscribe messaging is a destination called a topic. Message publishers send messages of specified topics. Clients that want to receive that type of message subscribe to the topic.

The publishers and subscribers never communicate with each other directly. Instead, they communicate by exchanging messages through a JMS provider.

Publishers and subscribers have a timing dependency. Clients that subscribe to a topic can consume only messages published after the client has created a subscription. In addition, the subscriber must continue to be active to consume messages.

Durable Subscriptions

Durable subscriptions allow subscribers to receive all the messages published on a topic, including those published while the subscriber is inactive. When the subscribing applications are not running, the messaging provider holds the messages in nonvolatile storage. It retains the messages until either:

The subscribing application becomes active, identifies itself to the provider, and sends an acknowledgment of receipt of the message.
The expiration time for the messages is reached.

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