[设计模式]之五:职责链模式

//统一处理接口
abstract class Handler {
	protected Handler handler;
	
	public void setHandler(Handler handler) {
		this.handler =  handler;
	}
	
	public abstract void HandlerRequest(int req);
}
//具体实现 处理不同的内容
public class ConcreteHandler1 extends Handler {

	@Override
	public void HandlerRequest(int req) {
		// TODO Auto-generated method stub
		if (req >= 0 && req < 10) {
			System.out.println("Handler1 handle " + req + " now");
		} else if (handler != null) {
			handler.HandlerRequest(req);
		}
	}

}
public class ConcreteHandler2 extends Handler {

	@Override
	public void HandlerRequest(int req) {
		// TODO Auto-generated method stub
		if (req >= 10 && req < 20) {
			System.out.println("Handler2 handle " + req + " now");
		} else if (handler != null) {
			handler.HandlerRequest(req);
		}
	}

}
public class ConcreteHandler3 extends Handler {

	@Override
	public void HandlerRequest(int req) {
		// TODO Auto-generated method stub
		if (req >= 20 && req < 30) {
			System.out.println("Handler3 handle " + req + " now");
		} else if (handler != null) {
			handler.HandlerRequest(req);
		}
	}

}
//客户代码
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Handler h1 = new ConcreteHandler1();
		Handler h2 = new ConcreteHandler2();
		Handler h3 = new ConcreteHandler3();
		
		h1.setHandler(h2);
		h2.setHandler(h3);
		
		List<Integer> list = new ArrayList<Integer>();
		list.add(2);
		list.add(5);
		list.add(14);
		list.add(22);
		list.add(18);
		list.add(3);
		list.add(27);
		list.add(20);
		
		for(Integer i : list) {
			h1.HandlerRequest(i);
		}
	}
//输出
Handler1 handle 2 now
Handler1 handle 5 now
Handler2 handle 14 now
Handler3 handle 22 now
Handler2 handle 18 now
Handler1 handle 3 now
Handler3 handle 27 now
Handler3 handle 20 now