用C#改写Head First Design Patterns--Decorator装饰（原创）

饮料的包装

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

namespace Decorator
{
//抽象组件类 饮料
public abstract class Beverage
{
public string description = "未知描述";
public Size size;
public abstract Size getsize();
public abstract string getDescription();
public abstract double cost();
}

//咖啡类
public class Coffe : Beverage
{
public override Size getsize()
{
return size;
}

public Coffe(Size s)
{

size = s;
if (this.getsize() == Size.Big)
{
description = "大Coffe";
}
if (this.getsize() == Size.Mid)
{
description = "中Coffe";
}
if (this.getsize() == Size.Small)
{
description = "小Coffe";
}
}

public override string getDescription()
{
return this.description;
}

public override double cost()
{
double d = 0;
if (this.getsize() == Size.Big)
{
d = 4.5;
}
if (this.getsize() == Size.Mid)
{
d = 3.5;
}
if (this.getsize() == Size.Small)
{
d = 2.5;
}
return d;
}
}

//茶类
public class Tea : Beverage
{
public override Size getsize()
{
return size;
}

public Tea(Size s)
{
size = s;
if (this.getsize() == Size.Big)
{
description = "大Tea";
}
if (this.getsize() == Size.Mid)
{
description = "中Tea";
}
if (this.getsize() == Size.Small)
{
description = "小Tea";
}
}

public override string getDescription()
{
return this.description;
}

public override double cost()
{

return 10;
}
}

//容器大小
public enum Size
{
Big,Small,Mid
}

//装饰者类 Decorator,其实也是继承饮料类,可用它也可不用
public abstract class Decorator : Beverage
{
//public abstract new string getDescription();
}

//材料：摩卡
public class Mocha : Beverage
{
Beverage bc;

public override Size getsize()
{
return bc.size;
}

public Mocha(Beverage b)
{
bc = b;
}

public override string getDescription()
{
return bc.getDescription() + "[+摩卡]";
}

public override double cost()
{
double d=bc.cost();
if (bc.getsize() == Size.Big)
{
d += 0.3;
}
if (bc.getsize() == Size.Mid)
{
d += 0.2;
}
if (bc.getsize() == Size.Small)
{
d += 0.1;
}
return d;
}
}

//材料：牛奶
public class Milk : Beverage
{
Beverage bc;

public override Size getsize()
{
return bc.size;
}

public Milk(Beverage b)
{
bc = b;
}

public override string getDescription()
{
return bc.getDescription() + "[+牛奶]";
}

public override double cost()
{
double d = bc.cost();
if (bc.getsize() == Size.Big)
{
d += 0.32;
}
if (bc.getsize() == Size.Mid)
{
d += 0.22;
}
if (bc.getsize() == Size.Small)
{
d += 0.12;
}
return d;
}
}

//材料：豆奶
public class Soy : Beverage
{
Beverage bc;

public override Size getsize()
{
return bc.size;
}

public Soy(Beverage b)
{
bc = b;
}

public override string getDescription()
{
return bc.getDescription() + "[+豆奶]";
}

public override double cost()
{
double d = bc.cost();
if (bc.getsize() == Size.Big)
{
d += 0.31;
}
if (bc.getsize() == Size.Mid)
{
d += 0.21;
}
if (bc.getsize() == Size.Small)
{
d += 0.11;
}
return d;
}
}

}

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

namespace Decorator
{
class Program
{
static void Main(string[] args)
{
//来一小杯茶
Beverage be = new Tea(Size.Small);

System.Console.WriteLine("饮料：" + be.getDescription() + ",价格：￥" + be.cost().ToString() + "人民币");

//添加牛奶
be = new Milk(be);
System.Console.WriteLine(be.GetType().ToString());
//添加摩卡
be = new Mocha(be);
System.Console.WriteLine(be.GetType().ToString());
System.Console.WriteLine("最后结账：" + be.getDescription() + ",价格：￥" + be.cost().ToString() + "人民币");

//来一大杯咖啡
Beverage Cof = new Coffe(Size.Mid);

System.Console.WriteLine("饮料：" + Cof.getDescription() + ",价格：￥" + Cof.cost().ToString() + "人民币");

//添加豆奶
Cof = new Soy(Cof);
System.Console.WriteLine(Cof.GetType().ToString());
//添加两次摩卡
Cof = new Mocha(Cof);
Cof = new Mocha(Cof);
System.Console.WriteLine(Cof.GetType().ToString());
System.Console.WriteLine("最后结账：" + Cof.getDescription() + ",价格：￥" + Cof.cost().ToString() + "人民币");
System.Console.ReadLine();

}
}
}