Convert the interface of an object into another interface clients expect. Adapter lets classes work together that couldn t otherwise because of incompatible interfaces. Structural Object Bridge Decouple an abstraction from its implementation so that the two can vary independently Structural Object Composite Compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly. Structural Object Decorator Attach additional responsibilities to an object dynamically.
Decorators provide a flexible alternative to subclassing for extending functionality.
Behavioral Class Template Method Define the skeleton of an algorithm in an operation, deferring some steps to subclasses. Template method lets subclasses redefine certain steps of an algorithm without changing the algorithm s structure Behavioral Object Chain of Responsibility Avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. Chain the receiving objects and pass the request along the chain until an object handles it. Behavioral Object Command Encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations Behavioral Object Iterator Provide a way to access the elements of an aggregate object sequentially, without exposing its underlying representation Behavioral Object Mediator Define an object that encapsulates how a set of objects interacts. The object will appear to change its state.