ORACLE APPLİCATİON DEVELOPMENT FRAMEWORK
Oracle ADF is based on the Model-View-Controller design pattern. An MVC application is separated into: 1) a model layer that handles interaction with data-sources and runs the business logic, 2) a view layer that handles the application user interface and, 3) a controller that manages the application flow and acts as the interface between the Model and the View layers.

Separating applications into these three layers simplifiys maintenance and reuse of components across applications. The independence of each layer from the others results in a loosly coupled, Service Oiented Architecture (SOA).

Oracle ADF implements MVC and further separates the model layer from the business services to enable service-oriented development of applications. The Oracle ADF achitecture is based on four layers:

• The Business Services layer- provides access to data from various sources and handles business logic.
• The Model layer- provides an abstraction layer on top of the business services layer, enabling the View and Controller layers to work with different implementations of Business Services in a consistent way.
• The Controller layer- provides a mechanism to control the flow of the Web application.
• The View layer- provides the user interace of the application.