Service Activator	Pattern Catalog  Previous   Next
	Site Home • Patterns Home • Table of Contents

An application has a service that it would like to make available to other applications.

How can an application design a service to be invoked both via various messaging technologies and via non-messaging techniques?

Design a Service Activator that connects the messages on the channel to the service being accessed.

A Service Activator can be one-way (request only) or two-way (Request-Reply). The service can be as simple as a method call—synchronous and non-remote—perhaps part of a Service Layer [EAA]. The activator can be hard-coded to always invoke the same service, or can use reflection to invoke the service indicated by the message. The activator handles all of the messaging details and invokes the service like any other client, such that the service doesn’t even know it’s being invoked through messaging.

Related patterns: Command Message, Competing Consumers, Event-Driven Consumer, Invalid Message Channel, Message Dispatcher, Message Endpoint, Messaging Gateway, Polling Consumer, Request-Reply, Transactional Client

For a full description of the pattern see:

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

Home • Patterns • Table of Contents

Previous   Next

© 2003 • Bobby Woolf • All rights reserved.