【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！