Decorator
The Decorator pattern makes it possible to add new/additional behavior/functionality to an existing class dynamically. This works by adding a decorator class, which has the same interface as the original (decorated) class. The decorator class wraps the original class which is usually achieved by passing the original object as a parameter to the constructor of the decorator when it is created.
The decorator pattern is an alternative to subclassing. While subclasssing adds behaviour at compile time, the decorator pattern can provide new funtionality at runtime.
Contents |
Typical Usage
Participating Classes
Component
Defines the abstract interface of the decorated object which can have added funtionality dynamically.
ConcreteComponent
Defines an object to which additional behaviour can be attached.
Decorator
Maintains a reference to the Component and defines a interface which complies to the Components interface.
ConcreteDecorator
Adds new functionality to the Component
