移动架构12_责任链模式

一、定义

使多个对象都有机会处理请求，从而避免了请求的发送者和接受者之间的耦合关系，将这些对象形成一条链，并沿着这条链传递该请求，直到有对象处理它为止。

二、使用场景

多个对象能够处理同一请求，具体处理则在运行时动态确定

在请求矗立者不明确的时候向多个对象提交同一个请求

需要动态制定一组对象处理请求

三、Demo

1.请求抽取：

public abstract class AbstractRequest {private Object object;public AbstractRequest(Object object){this.object=object;}/*** 具体的内容对象* @return*/public Object getContent(){return object;}/*** 获取请求级别*/public abstract int getRequestLevel();}

2、处理抽取

public abstract class Handler {public Handler nextHandler;public void handleRequest(AbstractRequest abstractRequest){if(getHandleLevel() == abstractRequest.getRequestLevel()){handle(abstractRequest);}else{if(nextHandler != null){nextHandler.handleRequest(abstractRequest);}else{System.out.println("->所有的处理对象都不能处理它");}}}/** * 每个处理对象的具体处理方式 * @param abstractRequest */public abstract void handle(AbstractRequest abstractRequest);/** * 每个对象处理的级别 * @return */public abstract int getHandleLevel();}

3、定义多个具体处理

public class Handler1 extends Handler {@Overridepublic void handle(AbstractRequest abstractRequest) {System.out.println("---handle1 处理请求："+abstractRequest.getRequestLevel());}@Overridepublic int getHandleLevel() {return 1;}}

public class Handler2 extends Handler {@Overridepublic void handle(AbstractRequest abstractRequest) {System.out.println("---handle2 处理请求："+abstractRequest.getRequestLevel());}@Overridepublic int getHandleLevel() {return 2;}}

public class Request3 extends AbstractRequest{public Request3(Object object) {super(object);}@Overridepublic int getRequestLevel() {return 3;}}

4、定义几个具体请求

public class Request1 extends AbstractRequest{public Request1(Object object) {super(object);}@Overridepublic int getRequestLevel() {return 1;}}

public class Request2 extends AbstractRequest{public Request2(Object object) {super(object);}@Overridepublic int getRequestLevel() {return 2;}}

public class Request3 extends AbstractRequest{public Request3(Object object) {super(object);}@Overridepublic int getRequestLevel() {return 3;}}

5使用

public class Client {public static void main(String[] args){Handler handler1 = new Handler1();Handler handler2 = new Handler2();Handler handler3 = new Handler3();handler1.nextHandler = handler2;handler2.nextHandler = handler3;AbstractRequest request3 = new Request3("请求3");handler1.handleRequest(request3);}}