Examples of proxy pattern and decoration pattern in Java

package test.design.proxydecorator; /** * 接口定义行为：吃饭 * @author lushuaiyin * */ public interface Eatable { void eatFood(); }

package test.design.proxydecorator; /** * 实现类 * @author lushuaiyin * */ public class Man implements Eatable{ @Override public void eatFood() { System.out.println("I am eating food! Happy!"); } }

package test.design.proxydecorator; /** * 代理模式 * 代理对象把被代理对象封装，像一个包装盒把被代理对象包裹起来。 * 它不改变被代理对象的原有逻辑，只是增加来了一些自己的服务，像一个代理一样。 * 代理从使用上给调用者的感觉就是你已经取代了原来的对象。 * 就像皇太后取代小皇帝实行垂帘听政。 * @author Administrator * */ public class ProxyMan implements Eatable{ private Eatable eatable; public ProxyMan(){ System.out.println("proxy: I am proxy object. I will help you create a object of Man that wnt to be proxyed"); this.eatable=new Man(); //注意代理对象把被代理对象封装，在内部有实际的被代理对象，这个调用者是不知道的。 } @Override public void eatFood() { //代理对象把被代理对象的功能封装，蛋不改变其内部逻辑，只是增加一些服务。 System.out.println("proxy: I know you are hungry,so I cook for you some food."); this.eatable.eatFood(); System.out.println("proxy: Now you eat up food. Let me help you clean the dishes."); } }

package test.design.proxydecorator; /** * 装饰的抽象. * 也可以不用抽象类，简单的父类也可以，只要实现装饰功能. * 抽象只是为了增加一层封装，规定装饰者必有的装饰功能而已。 * @author lushuaiyin * */ public abstract class DecoratorMan { protected Eatable eatable; //使用构造函数或者set方法（或其他方法）把接口对象传入。 //注意，必须保证这个对象的传入，最好还是用构造函数。 public DecoratorMan(Eatable eatable){ this.eatable=eatable; } public void eatFood(){ this.eatable.eatFood(); }; }

package test.design.proxydecorator; /** * 装饰模式 * 装饰对象时独立于原来的对象的。它和被装饰的对象有关系，但是是独立的对象。 * 装饰对象更像一个酒店服务生，为别人提供服务，所以他还是他自己，他有自己的实际存在。 * @author lushuaiyin * */ public class Decorator extends DecoratorMan{ public Decorator(Eatable eatable) { super(eatable); } //重写父类方法 public void eatFood(){ decoratorServiceCookFood();//装饰的具体行为 super.eatable.eatFood(); decoratorServiceCleanDishes();//装饰的具体行为 }; public void decoratorServiceCookFood(){ System.out.println("Decorator: I know you are hungry,so I cook for you some food."); } public void decoratorServiceCleanDishes(){ System.out.println("Decorator: Now you eat up food. Let me help you clean the dishes."); } }

package test.design.proxydecorator; public class TestMain { /** * @param args */ public static void main(String[] args) { //代理模式 System.out.println("代理模式:"); Man m1=new Man();//通常情况下 m1.eatFood(); System.out.println("---------------------------"); //代理模式者直接取代某对象，你连你想要见的人的面都见不到。 //它说你要见的人已经把所有事委托于我，他会的我会；他不会的，我也会。我就是他的替代增强版。 Eatable e1=new ProxyMan(); e1.eatFood(); System.out.println("------------分割---------------"); System.out.println("装饰模式:"); Man m2=new Man();//通常情况下 m2.eatFood(); System.out.println("---------------------------"); //装饰模式者站在一边提供各种服务. //装饰者和被装饰者都在场，装饰者提供服务，赚取小费。 Decorator d1=new Decorator(m2); d1.eatFood(); } }

代理模式: I am eating food! Happy! --------------------------- proxy: I am proxy object. I will help you create a object of Man that wnt to be proxyed proxy: I know you are hungry,so I cook for you some food. I am eating food! Happy! proxy: Now you eat up food. Let me help you clean the dishes. ------------分割--------------- 装饰模式: I am eating food! Happy! --------------------------- Decorator: I know you are hungry,so I cook for you some food. I am eating food! Happy! Decorator: Now you eat up food. Let me help you clean the dishes.