Software Architecture Design Patterns in Java

19 DECORATOR

This pattern was previously described in GoF95.

DESCRIPTION

The Decorator Pattern is used to extend the functionality of an object dynamically without having to change the original class source or using inheritance. This is accomplished by creating an object wrapper referred to as a Decorator around the actual object.

CHARACTERISTICS OF A DECORATOR

• The Decorator object is designed to have the same interface as the underlying object. This allows a client object to interact with the Decorator object in exactly the same manner as it would with the underlying actual object.
• The Decorator object contains a reference to the actual object.
• The Decorator object receives all requests (calls) from a client. It in turn forwards these calls ...