The Strategy Pattern is a design pattern to encapsulate the variants (algorithms) and swap them strategically to alter system behavior without changing its architecture. According to GoF, Strategy Pattern is intended to, Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
Strategy Pattern has three participants that include Strategy, Concrete Strategy and Context.
原文：http://www.cnblogs.com/windy86/p/3974465.html