strategy


layout: pattern
title: Strategy
folder: strategy
permalink: /patterns/strategy/
categories: Behavioral
tags:

– 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.

Class diagram

alt text

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

Tutorial

Credits

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