Facade

Thursday, 20 January 2005 21:21

Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.

Source Code

/**
 * Knows which subsystem classes are responsible for a request.
 * Delegates client requests to appropiate susystem objects.
 * @role __Facade
 */
public class Facade {
        /** reference to particular subsystem */
        private SubsystemA theSubsystemA;        /** reference to particular subsystem */
        private SubsystemB theSubsystemB;        /** this method is called by client */
        public void facadeMethod() {
                // multiple subsystems could be involved
                // to provide some functionality
        }
}

/**
 * Implements subsystem functionality. Handles work assigned by the Facade object.
 * Has no knowledge of the facade.
 * @role __System
 */
public class SubsystemA {
        /** some functionality */
        public void subsystemFunctionality() {
        }
}

/**
 * Implements subsystem functionality. Handles work assigned by the Facade object.
 * Has no knowledge of the facade.
 * @role __System
 */
public class SubsystemB {
        /** some functionality */
        public void subsystemFunctionality() {
        }
}