You want to invoke services asynchronously.
- You want to invoke business services, POJOs, or EJB components in
an asynchronous manner.
- You want to integrate publish/subscribe and point-to-point messaging
to enable asynchronous processing services.
- You want to perform a business task that is logically composed of
several business tasks.
Use a Service Activator to receive asynchronous requests
and invoke one or more business services.
- POJO Service Activator Strategy
- MDB Service Activator Strategy
- Service Activator Aggregator Strategy
- Response Strategies
- Database Response Strategy
- Email Response Strategy
- JMS Message Response Strategy
- Integrates JMS into enterprise applications
- Provides asynchronous processing for any business-tier component
- Enables standalone JMS listener
- Session Façade
The Session Façade encapsulates the complexity of the system
and provides coarse-grained access to business objects. A Service Activator
can access a Session Façade as a business service to invoke business
- Application Services
An Application Service can also be a kind of business service that a
Service Activator invokes to process the request.
- Business Delegate
The Service Activator typically uses a Business Delegate to access a
Session Façade. This results in simpler code for the Service
Activator and results in Business Delegate reuse across different tiers.
- Service Locator
The client can use the Service Locator pattern to look up and create
JMS-related service objects. The Service Activator can use the Service
Locator pattern to look up and create enterprise bean components.
- Half-Sync/Half-Async [POSA2]
The Service Activator is related to the Half-Sync/Half-Async pattern.
The pattern describes architectural decoupling by suggesting different
layers for synchronous and asynchronous processing, and an intermediate
queuing layer in between.
- Aggregator [EIP]
The Aggregator pattern discusses the problem of converting a request
into several asynchronous tasks and aggregating the results. The Service
Activator Aggregator strategy is based on similar concepts.