5.某咖啡店当卖咖啡时，可以根据顾客的要求在其中加入各种配料，咖啡店会根据所加入的配料来计算费用。咖啡店所供应的咖啡及配料的种类和价格如下表所示。
现采用装饰器（Decorator）模式来实现计算费用的功能，得到如图6-1所示的类图
【Java代码】
import java.util.*;
（1）class Beverage{//饮料
String description="Unknown Beverage";
public（2）（ ）{return description;}
public（3）;
}
abstract class CondimentDecorator extends Beverage{//配料
（4）;
}
class Espresso extends Beverage{//蒸馏咖啡
private final int ESPRESSO_PRICE=25;
public Espresso（ ）{description="Espresso";}
public int cost（ ）{return ESPRESSO_PRICE;}
}
class DarkRoast extends Beverage{//深度烘焙咖啡
private finalint DARKROAST_PRICE=20;
public DarkRoast0{description="DarkRoast";}
public int cost（ ）{rcturn DARKROAST PRICE;}
}
class Mocha extends CondimentDecorator{//摩卡
private final int MOCHA_PRICE=10;
public Mocha（Beverage beverage）{
this.beverage=beverage;
}
public String getDescription（ ）{
return beverage.getDescription0+"，Mocha";
}
public int cost（ ）{
return MOCHA_PRICE+beverage.cost（ ）;
}
}
class Whip extends CondimentDecorator{//奶泡
private finalint WHIP_PRICE=8;
public Whip（Beverage beverage）{this.beverage=beverage;}
public String getDescription（ ）{
return beverage.getDescription（ ）+"，Whip";
}
public int cost（ ）{return WHIP_PRICE+beverage.cost（ ）;}
}
public class Coffee{
public static void main(String args[]){
Beverage beverage=new DarkRoast（ ）;
beverage=new Mocha((5));
beverage=new Whip((6));
System.out.println(beverage.getDescription0+"￥"+beverage.cost（ ）);
}
}
编译运行上述程序，其输出结果为：
DarkRoast，Mocha，Whip￥38
