It is other main category of design patterns. Application design can be immensely simplified by applying Java EE design patterns. Java EE design patterns have been documented in Sun's Java Blueprints. These Java EE design patterns provide time-tested solution guidelines and best practices for object interaction in the different layer of a Java EE application. These design patterns are specifically concerned with the following listed layers:
- Design pattern at presentation layer
- Design pattern at business layer
- Design pattern at integration layer
These design patterns are specifically concerned with the following listed layers.
- Design pattern at presentation layer:
- View Helper: It separates views from the business logic of an enterprise J2EE application.
- Front Controller: It provides a single point of action to handle the all coming requests to the J2EE web application, it forwards the request to specific application controller to access model and view for presentation tier resources.
- Application Controller-The request actually handled by the Application Controller, it acts as a front controller helper. It responsible for the coordination with the business models and view components.
- Dispatcher View-It is related to the view only and it executes without business logic to prepare a response to the next view.
- Intercepting filters -In the J2EE web application, you could configure multiple interceptors for pre and post processing an user's request such as tracking and auditing user's requests.
- Design pattern at business layer:
- Business Delegate-It acts as a bridge between application controllers and business logic
- Application Service-It provides business logics to implement the model as simple Java objects for presentation layer
- Design pattern at integration layer:
- Data Access Object-It is implemented for accessing business data and it separates data access logic from business logic in the enterprise application.
- Web Service Broker-It encapsulates the logic to access the external application's resources and it is exposed as web services.