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An application is using Messaging. However, it cannot process messages as fast as they’re being added to the channel.

How can a messaging client process multiple messages concurrently?

Create multiple Competing Consumers on a single channel so that the consumers can process multiple messages concurrently.

Competing Consumers are multiple consumers that are all created to receive messages from a single Point-to-Point Channel. When the channel delivers a message, any of the consumers could potentially receive it. The messaging system's implementation determines which consumer actually receives the message, but in effect the consumers compete with each other to be the receiver. Once a consumer receives a message, it can delegate to the rest of its application to help process the message. (This solution only works with Point-to-Point Channels; multiple consumers on a Publish-Subscribe Channel just create more copies of each message.)

Related patterns: Event-Driven Consumer, Message, Message Channel, Message Dispatcher, Messaging, Point-to-Point Channel, Polling Consumer, Publish-Subscribe Channel, Transactional Client

For a full description of the pattern see:

Enterprise Integration Patterns Gregor Hohpe and Bobby Woolf ISBN 0321200683 650 pages Addison-Wesley

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