JMS defines two messaging models:
The publish-and-subscribe (pub/sub) model is a one-to-many model. The application sending the message is called the “message producer,” and the applications receiving the message are called “message consumers.” Message consumers establish subscriptions to register an interest in messages sent to a topic. A topic is the destination of this message model.
There are two types of subscriptions you can establish in the pub/sub model:
Durable – retains messages for the message consumer even when the message consumer application is not connected. The message provider, rather than Adaptive Server, retains the message.
Nondurable – retains messages only when consumer applications are connected to the message provider.
The point-to-point model is a one-to-one model, in that any message sent, by an application called a “message sender,” can be read only by one receiving application, called a “message receiver.” The destination of a point-to-point message is a queue. A queue may contain more than one active message receiver, but the messaging provider ensures that the message is delivered to only one message receiver.
