TIBCO EMS| JMS Message Models

JMS Message Models

JMS is based on creation and delivery of messages. Messages are structured data that one application sends to another. The creator of the message is known as the producer and the receiver of the message is known as the consumer. The TIBCO EMS server acts as an intermediary for the message and manages its delivery to the correct destination.

JMS supports these messaging models:

• Point-to-Point (queues)

• Publish and subscribe (topics)

• Multicast (topics)

Point-to-Point

Point-to-point messaging has one producer and one consumer per message. This style of messaging uses a queue to store messages until they are received. The message producer sends the message to the queue; the message consumer retrieves messages from the queue and sends acknowledgement that the message was received.

More than one producer can send messages to the same queue, and more than one consumer can retrieve messages from the same queue. The queue can be configured to be exclusive, if desired. If the queue is exclusive, then all queue messages can only be retrieved by the first consumer specified for the queue. Exclusive queues are useful when you want only one application to receive messages for a specific queue. If the queue is not exclusive, any number of receivers can retrieve messages from the queue. Non-exclusive queues are useful for balancing the load of incoming messages across multiple receivers. Regardless of whether the queue is exclusive or not, only one consumer can ever consume each message that is placed on the queue.

Publish and Subscribe

In a publish and subscribe message system, producers sends messages to a topic. In this model, the producer is known as a publisher and the consumer is known as a subscriber. Many publishers can publish to the same topic, and a message from a single publisher can be received by many subscribers. Subscribers subscribe to topics, and all messages published to the topic are received by all subscribers to the topic.

This type of message protocol is also known as broadcast messaging because messages are sent over the network and received by all interested subscribers, similar to how radio or television signals are broadcast and received.

Durable Subscribers for Topics

By default, subscribers only receive messages when they are active. If messages arrive on the topic when the subscriber is not available, the subscriber does not receive those messages.

The EMS APIs allow you to create durable subscribers to ensure that messages are received, even if the message consumer is not currently running. Messages for durable subscriptions are stored on the server as long as durable subscribers exist for the topic, or until the message expiration time for the message has been reached, or until the storage limit has been reached for the topic. Durable subscribers can receive messages from a durable subscription even if the subscriber was not available when the message was originally delivered.

When an application restarts and recreates a durable subscriber with the same ID, all messages stored on the server for that topic are delivered to the durable subscriber.