Service Activator - Enterprise Integration Patterns

Messaging Patterns

Service Activator

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.

... Read the entire pattern in the book Enterprise Integration Patterns

Integration Pattern Language

Correlation Identifier

Composed Msg. Processor

Message
Transformation

Event-driven Consumer

Point-to-Point Channel

Publish-Subscr. Channel

Datatype Channel

Invalid Message Channel

Integration Styles
Table of Contents
Preface
Introduction
Solving Integration Problems using Patterns
File Transfer
Shared Database
Remote Procedure Invocation
Messaging
Messaging Systems
Message Channel
Message
Pipes and Filters
Message Router
Message Translator
Message Endpoint
Messaging Channels
Point-to-Point Channel
Publish-Subscribe Channel
Datatype Channel
Invalid Message Channel
Dead Letter Channel
Guaranteed Delivery
Channel Adapter
Messaging Bridge
Message Bus
Message Construction
Command Message
Document Message
Event Message
Request-Reply
Return Address
Correlation Identifier
Message Sequence
Message Expiration
Format Indicator
Interlude: Simple Messaging
JMS Request/Reply Example
.NET Request/Reply Example
JMS Publish/Subscribe Example
Message Routing
Content-Based Router
Message Filter
Dynamic Router
Recipient List
Splitter
Aggregator
Resequencer
Composed Msg. Processor
Scatter-Gather
Routing Slip
Process Manager
Message Broker
Message Transformation
Envelope Wrapper
Content Enricher
Content Filter
Claim Check
Normalizer
Canonical Data Model
Interlude: Composed Messaging
Synchronous (Web Services)
Asynchronous (MSMQ)
Asynchronous (TIBCO)
Messaging Endpoints
Messaging Gateway
Messaging Mapper
Transactional Client
Polling Consumer
Event-Driven Consumer
Competing Consumers
Message Dispatcher
Selective Consumer
Durable Subscriber
Idempotent Receiver
Service Activator
System Management
Control Bus
Detour
Wire Tap
Message History
Message Store
Smart Proxy
Test Message
Channel Purger
Interlude: Systems Management Example
Instrumenting Loan Broker
Integration Patterns in Practice
Case Study: Bond Trading System
Concluding Remarks
Emerging Standards
Appendices
Bibliography
Revision History

You can reuse the following elements under the Creative Commons Attribution license: pattern icon, pattern name, problem and solution statements (in bold), and the sketch. Other portions are protected by copyright.

Enterprise Integration Patterns
The classic, as relevant as ever. Over 90,000 copies sold.

The Software Architect Elevator
Learn how architects can play a critical role in IT transformation by applying their technical, communication, and organizational skills.

Cloud Strategy
Fill the large gap between high-level goals and product details by understanding decision trade-offs.