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(Head First 设计模式)学习笔记(1)

以下内容转载请注明来自"菩提树下的杨过(http://blog.sqlsky.com)"

把书中开篇duck问题的代码翻译成了c#版:

概述:
某游戏公司要设计一款鸭子的游戏，里面有各种各样的鸭子，有些会飞，有些会叫，但都会游泳。而且不同种类的鸭子，飞行方式和叫唤的方式各不相同

以下代码体现了二个oo原则:
1.找出应用中可能需要变化之外，把它们独立出来，不要和那些不需要变化的代码混在一起
2.针对接口编程，而不是针对实现编程

Duck抽象类:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// 鸭子的抽象类

/// </summary>

public abstract class Duck

{

//注:以下二个变量，当然可以做成属性，但是从oo的角度考虑，这二个是代表duck的具体行为的，还是用实例变量比较恰当

protected FlyBehavior flyBehavior = null;

protected QuackBehavior quackBehavior = null;

/// <summary>

/// 开始叫唤

/// </summary>

public void StartQuack()

{

quackBehavior.Quack();

}

/// <summary>

/// 开始飞行　

/// </summary>

public void StartFly()

{

flyBehavior.Fly();

}

/// <summary>

/// 游泳(所有的鸭子都会swim)

/// </summary>

public void Swim()

{

Console.WriteLine("All the ducks can swim.");

}

/// <summary>

/// 抽象方法(返回具体鸭子的描述)

/// </summary>

public abstract void Display();

}

飞行行为接口:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// 飞行行为接口

/// </summary>

public interface FlyBehavior

{

/// <summary>

/// Fly方法，必须由实现该接口的类实现

/// </summary>

void Fly();

}

叫唤行为接口:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// "叫"行为接口

/// </summary>

public interface QuackBehavior

{

void Quack();

}

几种不同飞行方式类:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// "用翅膀飞"类(普通鸭子的飞行行为)

/// </summary>

public class FlyWithWings:FlyBehavior

{

public void Fly()

{

Console.WriteLine("I can fly with wing.");

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// "不会飞"类(橡皮鸭，模型鸭的飞行行为)

/// </summary>

public class FlyNoWay:FlyBehavior

{

public void Fly()

{

Console.WriteLine("Don't be fool! I can't fly.");

}

几种不同方式的叫唤类:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// "呱呱叫"类(普通鸭子的quack行为)

/// </summary>

public class NormalQuack:QuackBehavior

{

public void Quack()

{

Console.WriteLine("ga ga ga

");

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// "吱吱叫"类(橡皮鸭子的quack行为)

/// </summary>

public class Squeak:QuackBehavior

{

public void Quack()

{

Console.WriteLine("zhi zhi zhi

");

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// "不会叫"类(模型鸭专用)

/// </summary>

public class Mute:QuackBehavior

{

public void Quack()

{

Console.WriteLine("I can't make sound");

}

几种不同类型的鸭子类

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// 红头鸭，会用翅膀飞，会呱呱叫

/// </summary>

public class RedHeadDuck:Duck

{

public RedHeadDuck()

{

this.flyBehavior = new FlyWithWings();

this.quackBehavior = new NormalQuack();

}

public override void Display()

{

Console.WriteLine("I am a real red-head-duck.");

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

/// <summary>

/// 模型鸭子，不会飞，不会叫

/// </summary>

public class ModelDuck:Duck

{

public ModelDuck()

{

this.flyBehavior = new FlyNoWay();

this.quackBehavior = new Mute();

}

public override void Display()

{

Console.WriteLine("I am a mute duck.I cannot fly and quack.");

}

/// <summary>

/// 允许模型鸭在运行时动态改变飞行行为(这里本人修改了下，原文中把这个方法放到了Duck抽象类中，即允许所有鸭子都可以动态修改飞行方式，但有可能出现橡皮鸭改变为能用翅膀飞的尴尬，呵呵)

/// </summary>

/// <param name="fb"></param>

public void SetFlyBehavior(FlyBehavior fb)

{

this.flyBehavior = fb;

}

最终测试:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace duck

{

class Program

{

static void Main(string[] args)

{

RedHeadDuck _redDuck = new RedHeadDuck();

_redDuck.Display();//I am a real red-head-duck.

_redDuck.StartFly();//I can fly with wing.

_redDuck.StartQuack();//ga ga ga

Console.WriteLine();

ModelDuck _modelDuck = new ModelDuck();

_modelDuck.Display();//I am a mute duck.I cannot fly and quack.

_modelDuck.StartFly();//Don't be fool! I can't fly.

_modelDuck.StartQuack();//I can't make sound

Console.WriteLine();

_modelDuck.SetFlyBehavior(new FlyWithWings());//动态改变模型鸭子的飞行行为特性

_modelDuck.StartFly();//I can fly with wing.

Console.ReadLine();

}

菩提树下的杨过 2008-05-08 22:37:24 整理于上海

Tag标签: Head First,设计模式,c#

posted @ 2008-05-08 22:43 菩提树下的杨过阅读(45) 评论(0) 编辑收藏所属分类: c#/FrameWork