2.4. Application Service

Application Service centralizes and aggregates behavior to provide a uniform service layer to the business tier services. An Application Service might interact with other services or Business Objects. An Application Service can invoke other Application Services and thus create a layer of services in your application. The Application Service pattern centralizes and aggregates business components. An application service could be thought of as a helper to the Session Façade that takes care of all the business logic and work flow.

UML representation


The following lists the benefits of using the Application Service pattern:
  • Centralizes and improves reusability of business logic
  • Simplifies the Session Façade by eliminating the business logic

When to Use

You should use the Application Service pattern when you:
  • Start to see duplicated business logic in the Session Façade