Wednesday, December 28, 2005
1. Iterator (high)
Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.
2. Decorator (medium)
Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.
3. Facade (high)
Provide a unified interface to a set of interfaces in a subsystem. Façade defines a higher-level interface that makes the subsystem easier to use.