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strategy/README.md

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+---
+layout: pattern
+title: Strategy
+folder: strategy
+permalink: /patterns/strategy/
+categories: Behavioral
+tags:
+ - Java
+ - Difficulty-Beginner
+ - Gang Of Four
+---
+
+## Also known as
+Policy
+
+## Intent
+Define a family of algorithms, encapsulate each one, and make them
+interchangeable. Strategy lets the algorithm vary independently from clients
+that use it.
+
+![alt text](./etc/strategy_1.png "Strategy")
+
+## Applicability
+Use the Strategy pattern when
+
+* many related classes differ only in their behavior. Strategies provide a way to configure a class either one of many behaviors
+* you need different variants of an algorithm. for example, you might define algorithms reflecting different space/time trade-offs. Strategies can be used when these variants are implemented as a class hierarchy of algorithms
+* an algorithm uses data that clients shouldn't know about. Use the Strategy pattern to avoid exposing complex, algorithm-specific data structures
+* a class defines many behaviors, and these appear as multiple conditional statements in its operations. Instead of many conditionals, move related conditional branches into their own Strategy class
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
+* [Functional Programming in Java: Harnessing the Power of Java 8 Lambda Expressions](http://www.amazon.com/Functional-Programming-Java-Harnessing-Expressions/dp/1937785467/ref=sr_1_1)