装饰者模式
类图：
/**
* 饮料的抽象类
*/
public abstract class Beverage {
protected String description = "Unknown Beverage";
public String getDescription() {
return description;
}
/**计算总价格的方法*/
public abstract double cost();
}
/**
* 饮料的子类 -》深培咖啡
*/
public class DarkRoast extends Beverage {
public DarkRoast() {
description = "DarkRoast";
}
@Override
public double cost() {
// TODO Auto-generated method stub
return 0.99;
}
}
/**
*饮料的子类-》浓缩咖啡
*/
public class Espresso extends Beverage {
public Espresso() {
description = "Espresso";
}
/**
* @see com.tj.decorator.Beverage#cost()
*/
@Override
public double cost() {
// TODO Auto-generated method stub
return 1.99;
}
}
/**
* 饮料的子类-》混合咖啡
*/
public class HouseBlend extends Beverage {
private Beverage be;
public HouseBlend( ) {
this.be=be;
description = "House Blend Coffee";
}
/**
* @see com.tj.decorator.Beverage#cost()
*/
@Override
public double cost() {
// TODO Auto-generated method stub
return 0.89;
}
}
/**装饰者类*/
public abstract class CondimentDecorator extends Beverage {
}
/**
*摩卡-》装饰类
*/
public class Mocha extends CondimentDecorator {
Beverage beverage;
public Mocha(Beverage beverage) {
this.beverage = beverage;
}
/**
* @see com.tj.decorator.CondimentDecorator#getDescription()
*/
@Override
public String getDescription() {
// TODO Auto-generated method stub
return beverage.getDescription() + ", Mocha";
}
/**
* @see com.tj.decorator.Beverage#cost()
*/
@Override
public double cost() {
// TODO Auto-generated method stub
return 0.20 + beverage.cost();
}
}
/**
*豆浆 -》装饰类
*/
public class Soy extends CondimentDecorator {
Beverage beverage;
public Soy(Beverage beverage) {
this.beverage = beverage;
}
/**
* @see com.tj.decorator.CondimentDecorator#getDescription()
*/
@Override
public String getDescription() {
// TODO Auto-generated method stub
return beverage.getDescription() + ", Soy";
}
/**
* @see com.tj.decorator.Beverage#cost()
*/
@Override
public double cost() {
return 0.15 + beverage.cost();
}
}
/**
*奶泡 -》装饰类
*/
public class Whip extends CondimentDecorator {
Beverage beverage;
public Whip(Beverage beverage) {
this.beverage = beverage;
}
/**
* @see com.tj.decorator.CondimentDecorator#getDescription()
*/
@Override
public String getDescription() {
// TODO Auto-generated method stub
return beverage.getDescription() + ", Whip";
}
/**
* @see com.tj.decorator.Beverage#cost()
*/
@Override
public double cost() {
// TODO Auto-generated method stub
return 0.10 + beverage.cost();
}
}
测试类：
public class Test {
public static void main(String[] args) {
System.out.println("-------单个物品-------");
Beverage beverage = new Espresso();// 饮料 1.99
System.out.println(beverage.getDescription() + " $" + beverage.cost());
System.out.println("-----装饰3个物品的方式之一---------");
Beverage beverage2 = new DarkRoast();// 饮料 0.99
beverage2 = new Mocha(beverage2);// 装饰者子类 0.2
beverage2 = new Mocha(beverage2);// 装饰者子类 0.2
beverage2 = new Whip(beverage2);// 装饰者子类 0.1
beverage2.cost();
System.out.println(beverage2.getDescription() + " $" + beverage2.cost());
System.out.println("-----装饰3个物品的方式之一---------");
Mocha mocha = new Mocha(new Mocha(new Whip(new DarkRoast())));
System.out.println(mocha.getDescription() + " $" + mocha.cost());
System.out.println("-----装饰3个物品的方式之一---------");
Beverage beverage3 = new HouseBlend();
beverage3 = new Soy(beverage3);
beverage3 = new Mocha(beverage3);
beverage3 = new Whip(beverage3);
System.out.println(beverage3.getDescription() + " $" + beverage3.cost());
}
}
输出日志： -------单个物品------- Espresso $1.99 -----装饰3个物品的方式之一--------- DarkRoast, Mocha, Mocha, Whip $1.49 -----装饰3个物品的方式之一--------- DarkRoast, Whip, Mocha, Mocha $1.49 -----装饰3个物品的方式之一--------- House Blend Coffee, Soy, Mocha, Whip $1.34
再上一个例子：
/**抽象的人 被装饰的抽象类*/
public abstract class Human {
public abstract double calcMoney();
public void run() {
System.out.println("在走路...");
}
}
/**装饰者抽象类*/
public abstract class Decorator extends Human{
public abstract double calcMoney();
}
/**
* 具体的人，被装饰者。
* @author hp
*
*/
public class ConcreateHuman extends Human{
private String name;
public ConcreateHuman(String name) {
this.name=name;
}
public String getName() {
return name;
}
@Override
public double calcMoney() {
//被装饰者自身携带了0大洋
return 0;
}
@Override
public void run() {
System.out.println(name+"在商场散步...");
}
}
/**
* 具体的装饰者。 赚取30RMB
*/
public class ConcreateDecoratorA extends Decorator{
private Human human;
public ConcreateDecoratorA(Human human) {
this.human=human;
}
@Override
public void run() {
super.run();
System.out.println("ConcreateDecoratorA.run()");
}
@Override
public double calcMoney() {
return human.calcMoney()+30;
}
public void saleCoffer(){
System.out.println("卖出一份咖啡");
}
}
/***
* 具体的装饰者。 赚取20RMB
*/
public class ConcreateDecoratorB extends Decorator {
private Human human;
public ConcreateDecoratorB(Human human) {
this.human=human;
}
public void saleMilk() {
System.out.println("卖出了 牛奶");
}
@Override
public double calcMoney() {
return human.calcMoney()+20;
}
}
public class Test {
public static void main(String[] args) {
/**方式1：*/
System.out.println("/**方式1：*/ ");
ConcreateHuman human = new ConcreateHuman("张无忌");
human.run();
System.out.println(human.getName()+"身上有："+human.calcMoney()+"RMB");
ConcreateDecoratorB concreateB = new ConcreateDecoratorB(human);
concreateB.saleMilk();
System.out.println(human.getName()+"身上有："+concreateB.calcMoney()+"RMB");
ConcreateDecoratorA concreateA = new ConcreateDecoratorA(concreateB);
concreateA.saleCoffer();
System.out.println(human.getName()+"身上有："+concreateA.calcMoney()+"RMB");
System.out.println("/**********************/");
System.out.println("/**********************/");
/**方式2：*/
System.out.println("/**方式2：一般用于计算总价*/ ");
Human huamnZhang = new ConcreateDecoratorA(new ConcreateDecoratorB(new ConcreateHuman("张无忌")));
System.out.println("身上有："+huamnZhang.calcMoney()+"RMB");
}
}
/**方式1：*/ 张无忌在商场散步... 张无忌身上有：0.0RMB 卖出了 牛奶 张无忌身上有：20.0RMB 卖出一份咖啡 张无忌身上有：50.0RMB /**********************/ /**********************/ /**方式2：一般用于计算总价*/ 身上有：50.0RMB