【GOF23设计模式】责任链模式

来源：http://www.bjsxt.com/ 
一、【GOF23设计模式】_责任链模式、公文审批、供应链系统的采购审批、异常链、过滤器和拦截器调用过程

 package com.test.chainOfResp;
 /**
  * 封装请假的基本信息
  */
 public class LeaveRequest {
     private String empName;
     private int leaveDays;
     private String reason;

     public LeaveRequest(String empName, int leaveDays, String reason) {
         super();
         this.empName = empName;
         this.leaveDays = leaveDays;
         this.reason = reason;
     }

     public String getEmpName() {
         return empName;
     }

     public void setEmpName(String empName) {
         this.empName = empName;
     }

     public int getLeaveDays() {
         return leaveDays;
     }

     public void setLeaveDays(int leaveDays) {
         this.leaveDays = leaveDays;
     }

     public String getReason() {
         return reason;
     }

     public void setReason(String reason) {
         this.reason = reason;
     }
 }

 package com.test.chainOfResp;
 /**
  * 抽象类
  */
 public abstract class Leader {
     protected String name;
     protected Leader nextLeader;//责任链上的后继对象

     public Leader(String name) {
         super();
         this.name = name;
     }
     //设定责任链上的后继对象
     public void setNextLeader(Leader nextLeader) {
         this.nextLeader = nextLeader;
     }

     /**
      * 处理请求的核心的业务方法
      * @param leaveRequest
      */
     public abstract void handleRequest(LeaveRequest leaveRequest);
 }

 package com.test.chainOfResp;
 /**
  * 主任
  */
 public class Director extends Leader{

     public Director(String name) {
         super(name);
     }

     @Override
     public void handleRequest(LeaveRequest leaveRequest) {
         if(leaveRequest.getLeaveDays() < 3){
             System.out.println("员工："+leaveRequest.getEmpName()+"请假，天数："+leaveRequest.getLeaveDays()+"，理由："+leaveRequest.getReason());
             System.out.println("主任："+this.name+"，审批通过！");
         }else{
             if(this.nextLeader != null){
                 this.nextLeader.handleRequest(leaveRequest);
             }
         }
     }
 }

 package com.test.chainOfResp;
 /**
  * 经理
  */
 public class Manager extends Leader{

     public Manager(String name) {
         super(name);
     }

     @Override
     public void handleRequest(LeaveRequest leaveRequest) {
         if(leaveRequest.getLeaveDays() < 10){
             System.out.println("员工："+leaveRequest.getEmpName()+"请假，天数："+leaveRequest.getLeaveDays()+"，理由："+leaveRequest.getReason());
             System.out.println("经理："+this.name+"，审批通过！");
         }else{
             if(this.nextLeader != null){
                 this.nextLeader.handleRequest(leaveRequest);
             }
         }
     }
 }

 package com.test.chainOfResp;
 /**
  * 总经理
  */
 public class GeneralManager extends Leader{

     public GeneralManager(String name) {
         super(name);
     }

     @Override
     public void handleRequest(LeaveRequest leaveRequest) {
         if(leaveRequest.getLeaveDays() < 30){
             System.out.println("员工："+leaveRequest.getEmpName()+"请假，天数："+leaveRequest.getLeaveDays()+"，理由："+leaveRequest.getReason());
             System.out.println("总经理："+this.name+"，审批通过！");
         }else{
             System.out.println("莫非"+leaveRequest.getEmpName()+"想辞职，居然请假"+leaveRequest.getLeaveDays()+"天！");
         }
     }
 }

 package com.test.chainOfResp;
 /**
  * 副总经理
  */
 public class ViceGeneralManager extends Leader{

     public ViceGeneralManager(String name) {
         super(name);
     }

     @Override
     public void handleRequest(LeaveRequest leaveRequest) {
         if(leaveRequest.getLeaveDays() < 20){
             System.out.println("员工："+leaveRequest.getEmpName()+"请假，天数："+leaveRequest.getLeaveDays()+"，理由："+leaveRequest.getReason());
             System.out.println("副总经理："+this.name+"，审批通过！");
         }else{
             if(this.nextLeader != null){
                 this.nextLeader.handleRequest(leaveRequest);
             }
         }
     }
 }

 package com.test.chainOfResp;

 public class Client {
     public static void main(String[] args) {
         Leader a = new Director("张三");
         Leader b = new Manager("李四");
         Leader b2 = new ViceGeneralManager("李小四");//新增逻辑，副总经理
         Leader c = new GeneralManager("王五");

         //组织责任链对象的关系
         a.setNextLeader(b);
         b.setNextLeader(b2);//新增关系
         b2.setNextLeader(c);

         //开始请假操作
         LeaveRequest leaveRequest = new LeaveRequest("Tom", 15, "回英国老家探亲！");
         a.handleRequest(leaveRequest);

     }
 }

控制台输出：
员工：Tom请假，天数：15，理由：回英国老家探亲！
副总经理：李小四，审批通过！