策略模式——HeadFirst学习笔记

1、策略模式：

定义了算法族，分别封装起来，让他们之间可以相互替换，此模式让算法的变化独立于使用算法的客户；

2、设计工具箱中解锁的工具：

面向对象设计基础：抽象、封装、多态、继承

面向对象原则：封装变化、都用组合少用继承、针对接口编程，不针对实现编程；

3、样例实现：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace StrategyPattern
{
    public interface FlyBehavor
    {
        string fly();
    }

    public class FlyWithWings : FlyBehavor
    {
        public string fly()
        {
            return "挥着翅膀的女孩";
        }
    }

    public class FlyNoWay : FlyBehavor
    {
        public string fly()
        {
            return "没有翅膀的天使";
        }
    }

    public interface QuackBehavor
    {
        string quack();
    }

    public class Quack : QuackBehavor
    {
         public string quack()
         {
             return "普通鸭子呱呱的浪叫";
         }
    }

    public class Squeak : QuackBehavor
    {
        public string quack()
        {
            return "橡皮鸭子吱吱骚叫";
        }
    }

    public class MuteQuack : QuackBehavor
    {
        public string quack()
        {
            return "人家是一个安静的美男子";
        }
    }

    public class Duck
    {
        protected FlyBehavor m_FlyBehavor;
        protected QuackBehavor m_QuackBehavor;

        public Duck()
        {         
        }

        public void setFlyBehavor(FlyBehavor flyBehavor)
        {
            m_FlyBehavor = flyBehavor;
        }

        public  string ferformQuack()
        {
            return m_QuackBehavor.quack();
        }

        public void setQuackBehavor(QuackBehavor quackBehavor)
        {
            m_QuackBehavor = quackBehavor;
        }

        public string performFly()
        {
            return m_FlyBehavor.fly();
        }

        public  string swim()
        {
            return "I am swimming!";
        }

        public virtual string display()
        {
            return string.Empty;
        }
    }

    public class MallardDuck : Duck
    {
        public MallardDuck()
        {
            m_FlyBehavor = new FlyWithWings();
            m_QuackBehavor = new Quack();
        }

        public override string display()
        {
            return "绿头鸭";
        }
    }

    public class RedHeadDuck:Duck
    {
        public override string display()
        {
            return "红头鸭";
        }
    }

    public class RubberDuck : Duck
    {
        public override string display()
        {
            return "橡皮鸭";
        }
    }
}

namespace StrategyPattern
{
    class Program
    {
        public static void print(string str)
        {
            Console.WriteLine(str);
        }

        static void Main(string[] args)
        {
            Duck pDuck = new MallardDuck();
            print(pDuck.display());
            print(pDuck.ferformQuack());
            print(pDuck.performFly());

            pDuck.setFlyBehavor(new FlyNoWay());
            print(pDuck.performFly());

            pDuck.setQuackBehavor(new Squeak());
            print(pDuck.ferformQuack());

        }
    }
}