行为型模式-责任链模式

　　行为型模式又可以分成以下四类：第一类：通过父类与子类的关系进行实现。第二类：两个类之间。第三类：类的状态。第四类：通过中间类

　　责任链模式属于第二类，两个类之间的关系

　　责任链即一项工作可能由多个实体中的一个完成，在工作未确定时，是不知道会由谁来完成的

　　下面来看一下代码

　　先看请求

package behavior.pattern.betweenclass.chainofresponsibility; //抽象请求类 public abstract class AbstractRequest { private String content = null; public AbstractRequest(String content) { this.content = content; } public String getContent() { return this.content; } // 获得请求的级别 public abstract int getRequestLevel(); } package behavior.pattern.betweenclass.chainofresponsibility; //具体请求类01 public class Request01 extends AbstractRequest { public Request01(String content) { super(content); } @Override public int getRequestLevel() { return Levels.LEVEL_01; } } package behavior.pattern.betweenclass.chainofresponsibility; //具体请求类02 public class Request02 extends AbstractRequest { public Request02(String content) { super(content); } @Override public int getRequestLevel() { return Levels.LEVEL_02; } } package behavior.pattern.betweenclass.chainofresponsibility; //具体请求类03 public class Request03 extends AbstractRequest { public Request03(String content) { super(content); } @Override public int getRequestLevel() { return Levels.LEVEL_03; } }

　　再看一下处理者

package behavior.pattern.betweenclass.chainofresponsibility; //抽象处理者类， public abstract class AbstractHandler { // 责任链的下一个节点，即处理者 private AbstractHandler nextHandler = null; // 捕获具体请求并进行处理，或是将请求传递到责任链的下一级别 public final void handleRequest(AbstractRequest request) { System.out.println("进入当前 处理者-0" + this.getHandlerLevel()); // 若该请求与当前处理者的级别层次相对应，则由自己进行处理 if (this.getHandlerLevel() == request.getRequestLevel()) { this.handle(request); } else { // 当前处理者不能胜任，则传递至职责链的下一节点 if (this.nextHandler != null) { System.out.println("当前 处理者-0" + this.getHandlerLevel() + " 不足以处理 请求-0" + request.getRequestLevel()); // 这里使用了递归调用 this.nextHandler.handleRequest(request); } else { System.out.println("职责链上的所有处理者都不能胜任该请求..."); } } System.out.println("离开当前 处理者-0" + this.getHandlerLevel()); } // 设置责任链中的下一个处理者 public void setNextHandler(AbstractHandler nextHandler) { this.nextHandler = nextHandler; } // 获取当前处理者的级别 protected abstract int getHandlerLevel(); // 定义链中每个处理者具体的处理方式 protected abstract void handle(AbstractRequest request); } package behavior.pattern.betweenclass.chainofresponsibility; //具体处理者-01 public class Handler01 extends AbstractHandler { @Override protected int getHandlerLevel() { return Levels.LEVEL_01; } @Override protected void handle(AbstractRequest request) { System.out.println("处理者-01 处理 " + request.getContent()); } } package behavior.pattern.betweenclass.chainofresponsibility; //具体处理者-02 public class Handler02 extends AbstractHandler { @Override protected int getHandlerLevel() { return Levels.LEVEL_02; } @Override protected void handle(AbstractRequest request) { System.out.println("处理者-02 处理 " + request.getContent()); } } package behavior.pattern.betweenclass.chainofresponsibility; //具体处理者-03 public class Handler03 extends AbstractHandler { @Override protected int getHandlerLevel() { return Levels.LEVEL_03; } @Override protected void handle(AbstractRequest request) { System.out.println("处理者-03 处理 " + request.getContent()); } } package behavior.pattern.betweenclass.chainofresponsibility; //全局变量，接口类型 /** * 使用Java中的interface定义全局变量，可根据具体需要在 * 具体的包中使用静态导入相关的全局变量，语法如下： * import static package01.package02.*; */ public interface Levels { public static final int LEVEL_01 = 1; public static final int LEVEL_02 = 2; public static final int LEVEL_03 = 3; }

　　测试代码

package behavior.pattern.betweenclass.chainofresponsibility; //测试类 public class Client { public static void main(String[] args) { // 创建指责链的所有节点 AbstractHandler handler01 = new Handler01(); AbstractHandler handler02 = new Handler02(); AbstractHandler handler03 = new Handler03(); // 进行链的组装，即头尾相连，一层套一层 handler01.setNextHandler(handler02); handler02.setNextHandler(handler03); // 创建请求并提交到指责链中进行处理 AbstractRequest request01 = new Request01("请求-01"); AbstractRequest request02 = new Request02("请求-02"); AbstractRequest request03 = new Request03("请求-03"); // 每次提交都是从链头开始遍历 handler01.handleRequest(request01); handler01.handleRequest(request02); handler01.handleRequest(request03); } }

　　运行结果

转载于:https://www.cnblogs.com/liunianfeiyu/p/10133832.html