/********************************************************************** * <pre> * FILE : Demo01.java * CLASS : Demo01 * * AUTHOR : Liaokailin * * FUNCTION : TODO * * *====================================================================== * CHANGE HISTORY LOG *---------------------------------------------------------------------- * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. *---------------------------------------------------------------------- *             |2014-3-6|Liaokailin| Created | * DESCRIPTION: * </pre> ***********************************************************************/package org.demo.decorate.demo01;/** * 动态地给一个对象添加一些额外的职责。就增加功能来说，Decorator模式相比生成子类更为灵活。 * 适用性    1.在不影响其他对象的情况下，以动态、透明的方式给单个对象添加职责。    2.处理那些可以撤消的职责。    3.当不能采用生成子类的方法进行扩充时。        参与者    1.Component    定义一个对象接口，可以给这些对象动态地添加职责。    2.ConcreteComponent    定义一个对象，可以给这个对象添加一些职责。    3.Decorator    维持一个指向Component对象的指针，并定义一个与Component接口一致的接口。    4.ConcreteDecorator    向组件添加职责。 *///componentinterface Person{    void eat() ;}//ConcreteComponent class Man implements Person{    @Override    public void eat() {        System.out.println("Man: eat");    }}//Decorate abstract class Decorator implements Person{    protected Person person ;    public void setPerson(Person person){        this.person = person ;    }    public void eat(){        person.eat() ;    }}//ConcreteDecorateclass ConcreteDecorate extends Decorator{    public void eat(){        System.out.println("wash before each meal");        super.eat() ;        System.out.println("wipe mouth");    }}public class Demo01 {   public static void main(String[] args) {    Man m = new Man() ;    ConcreteDecorate c = new ConcreteDecorate() ;    c.setPerson(m) ; //装饰man    c.eat() ;}}

wash before each mealMan: eatwipe mouth

/********************************************************************** * <pre> * FILE : Demo02.java * CLASS : Demo02 * * AUTHOR : Liaokailin * * FUNCTION : TODO * * *====================================================================== * CHANGE HISTORY LOG *---------------------------------------------------------------------- * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. *---------------------------------------------------------------------- *             |2014-3-6|Liaokailin| Created | * DESCRIPTION: * </pre> ***********************************************************************/package org.demo.decorate.demo02;interface DrinkComponent{    float getTotalCost() ;    String getDescription() ;}class Espresso implements DrinkComponent{    private String description = "Espresso" ;    private float cost = 0.75f  ;    public float getTotalCost() {        return cost;    }    public String getDescription() {        return description;    }}class EspressoConPanna implements DrinkComponent {      private String description = "EspressoConPare";      private float cost = 1;      public float getTotalCost() {        return cost;      }      public String getDescription() {        return description;      }    }abstract class Decorator implements DrinkComponent{    protected DrinkComponent component ;    public Decorator(DrinkComponent component){        this.component = component ;    }    @Override    public float getTotalCost(){        return component.getTotalCost() ;    }         public String getDescription() {            return component.getDescription();      }}class ExtraEspresso extends Decorator{    private float cost = 1f ;    public ExtraEspresso(DrinkComponent component){        super(component) ;    }    @Override    public float getTotalCost() {        return super.getTotalCost()+cost;    }    @Override    public String getDescription() {        return super.getDescription() +"extra espresso";    }    }public class Demo02 {   public static void main(String[] args) {       Espresso espresso = new Espresso() ; //DrinkComponent ;       ExtraEspresso decorate = new ExtraEspresso(espresso) ;       System.out.println("coffer:"+decorate.getDescription()+";totalCost:"+decorate.getTotalCost() );       }}

coffer:Espressoextra espresso;totalCost:1.75

/********************************************************************** * <pre> * FILE : Demo03.java * CLASS : Demo03 * * AUTHOR : Liaokailin * * FUNCTION : TODO * * *====================================================================== * CHANGE HISTORY LOG *---------------------------------------------------------------------- * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ. *---------------------------------------------------------------------- *             |2014-3-6|Liaokailin| Created | * DESCRIPTION: * </pre> ***********************************************************************/package org.demo.decorate.demo03;/** * 写一个简单的系统， * 用decorator模式模拟以下情况： * 有些鸟会飞而有一些不会， * 有一些鸟会游泳而有一些不会， * 还有一些既会飞又会游泳。 *  * 分析  如果写一个bird类 然后继承生成各种bird  这显然不合理的  bird太多  导致子类过多 。 * 但是为了给bird增加一些功能  如： fly swim */ interface Bird{    void type() ; //类型 }class Bird01 implements Bird{    public void type() {        System.out.print(" a bird :");    }} abstract class Decorator implements Bird{    protected Bird bird ;    public Decorator(Bird bird){        this.bird = bird ;    }        public void type(){        bird.type() ;    }}class Decorator01 extends Decorator{    public Decorator01(Bird bird) {        super(bird);    }    @Override    public void type() {        super.type();        System.out.println(" only can fly ");    }} class Decorator02 extends Decorator{    public Decorator02(Bird bird) {        super(bird);    }    @Override    public void type() {        super.type();        System.out.println(" only can swim ");    }} class Decorator03 extends Decorator{    public Decorator03(Bird bird) {        super(bird);    }    @Override    public void type() {        super.type();        System.out.println(" not only fly,but also swim ");    }} public class Demo03 {    public static void main(String[] args) {        Bird b = new Bird01() ;        Decorator d1 = new Decorator03(b) ;        d1.type();    }}

 a bird : not only fly,but also swim