责任链模式

[color=red]【责任链模式】使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这些对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止。[/color]

package com.demo.chain;

import java.util.ArrayList;

public class Beijing implements Handler {

	//存放当前处理者后继的Handler接口变量
	private Handler handler;
	//存放身份证号的数组线性表
	private ArrayList<String> numberList;
	Beijing(){
		numberList=new ArrayList<String>();
		numberList.add("0001");
		numberList.add("0002");
		numberList.add("0003");
		numberList.add("0004");
	}
	@Override
	public void handleRequest(String number) {
		// TODO Auto-generated method stub
		if(numberList.contains(number))
			System.out.println("北京人");
		else
			if(handler!=null)
				//将请求传给下一个处理者
				handler.handleRequest(number);
	}
	@Override
	public void setNextHandler(Handler handler) {
		// TODO Auto-generated method stub
		this.handler=handler;
	}
}

package com.demo.chain;

public class Application {

	//责任链上的对象
	private Handler beijing,shanghai,shenzhen;
	//建立责任链
	public void createChain(){
		beijing=new Beijing();
		shanghai=new Shanghai();
		shenzhen=new Shenzhen();
		beijing.setNextHandler(shanghai);
		shanghai.setNextHandler(shenzhen);
	}
	//相应用户请求
	public void reponseClient(String number){
		beijing.handleRequest(number);
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Application application=new Application();
		application.createChain();
		application.reponseClient("0009");
	}
}