Decorator Design Pattern
The informal description: Excerpts from [Gamma et al. 1995] (adapted for this purpose):
Intent: Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.
Structure: Original OMT diagram converted to UML (Why and How?):
Collaborations: Decorator forwards requests to its Component object. It may optionally perform additional operations before and after forwarding the request.
|Decorator in LePUS3 (legend)|
|Decorator in Class-Z (legend)|