装饰器模式（网站借鉴的）

package com.decorator;/** * 面包类 * @author Administrator * */public class Bread extends Ingredient {    private String description ;    public Bread(String desc){              this.description=desc ;    }    public String getDescription(){              return description ;    }           public double getCost(){              return 2.48 ;    }       }package com.decorator;public class Celery extends Decorator{    public Celery(Ingredient igd){              super(igd);    }    public String getDescription(){              String base = ingredient.getDescription();              return base +"\n"+"Decrocated with Celery !";    }    public double getCost(){              double basePrice = ingredient.getCost();              double celeryPrice =0.6;              return      basePrice + celeryPrice ;    }}package com.decorator;public abstract class Decorator extends Ingredient {    Ingredient ingredient ;    public Decorator(Ingredient igd){             this.ingredient = igd;         }           public abstract String getDescription();    public abstract double getCost();}package com.decorator;public class GreenGrocery extends Decorator{    public GreenGrocery (Ingredient igd){              super(igd);    }    public String getDescription(){              String base = ingredient.getDescription();              return base +"\n"+"Decrocated with GreenGrocery  !";    }    public double getCost(){              double basePrice = ingredient.getCost();              double greenGroceryPrice = 0.4;              return        basePrice + greenGroceryPrice ;    }}package com.decorator;/** * 原料类  * @author Administrator * */public abstract class Ingredient {         public abstract String getDescription();         public abstract double getCost();             public void printDescription(){                           System.out.println(" Name      "+ this.getDescription());                   System.out.println(" Price RMB "+ this.getCost());         }}package com.decorator;public class Mutton extends Decorator{    public Mutton(Ingredient igd){              super(igd);    }    public String getDescription(){              String base = ingredient.getDescription();              return base +"\n"+"Decrocated with Mutton !";    }    public double getCost(){              double basePrice = ingredient.getCost();              double muttonPrice = 2.3;              return        basePrice + muttonPrice ;    }}package com.decorator;public class Pork extends Decorator{    public Pork(Ingredient igd){              super(igd);    }    public String getDescription(){              String base = ingredient.getDescription();              return base +"\n"+"Decrocated with Pork !";    }    public double getCost(){              double basePrice = ingredient.getCost();              double porkPrice = 1.8;              return        basePrice + porkPrice ;    }}package com.decorator;public class DecoratorTest {public static void main(String[] args){   Ingredient compound = new Mutton(new Celery(new Bread("Master24's Bread")));                         compound.printDescription();                     compound = new Celery(new GreenGrocery(new Bread("Bread with milk")));               compound.printDescription();                     compound = new Mutton(new Pork(new Bread("Bread with cheese")));           compound.printDescription();}}