WSO2 ESB comes with a built-in Qpid server (New in version 4.0). Apache Qpid™ is a cross-platform Enterprise Messaging system which implements the Advanced Message Queuing Protocol (AMQP). Enterprise Messaging systems let programs communicate by exchanging messages.
With ESB, the Qpid Server can be used as:
- a JMS provider with the JMS transport or
- as an event broker with the Event Mediator.
Event sources feature has been completely removed in version 4.0. Event Source - A Web service that sends notifications and accepts requests to create subscriptions. Event sources delivered events to event sinks. This functionality is now provided by the built-in Qpid broker. Qpid Broker component is embedded to the CEP Server. If the Carbon broker type is JMS, user can use this component to receive and publish events. Qpid Broker can be used as a JMS provider or an event broker for pub-sub messaging.
Message Broker
A Message Broker (New in Version 4.0) is a built-in JMS provider/broker powered by Apache Qpid. The primary aim of the message broker is is to provide a persistence and broker functionality across Carbon. Once the task is completed, users of Carbon should have an embedded broker such as Apache ActiveMQ which they can consume across the Carbon.
Note
You can find information on how to setup WSO2 ESB and Apache Qpid from scratch in ESB and Apache Qpid (relates to ESB version 3.0 or earlier.)