设计模式 职责链模式

概述

结构

案例

编写请假条类

@Data
@AllArgsConstructor
public class LeaveRequest {
    private String name;
    private int num;
    private String content;
}

编写处理者抽象类

public abstract class Handler {
    protected final static int NUM_ONE = 1;
    protected final static int NUM_THREE = 3;
    protected final static int NUM_SEVEN = 7;

    private int numStart;
    private int numEnd;

    //领导上面还有领导
    private Handler nextHandler;

    public Handler(int numStart){
        this.numStart = numStart;
    }

    public Handler(int numStart,int numEnd){
        this.numStart = numStart;
        this.numEnd = numEnd;
    }

    public void setNextHandler(Handler nextHandler) {
        this.nextHandler = nextHandler;
    }

    public final void submit(LeaveRequest request){
        if(0 == this.numStart){
            return;
        }
        if(request.getNum() >= this.numStart){
            this.handleLeave(request);
            if(null != this.nextHandler && request.getNum() > this.numEnd){
                this.nextHandler.submit(request);
            }
            else {
                System.out.println("流程结束");
            }
        }
    }

    protected abstract void handleLeave(LeaveRequest request);
}

编写小组组长 部门经理 总经理

public class GroupLeader extends Handler{
    public GroupLeader() {
        super(Handler.NUM_ONE, Handler.NUM_THREE);
    }

    @Override
    protected void handleLeave(LeaveRequest request) {
        System.out.println(request.getName() + "请假" + request.getNum() + "天" +request.getContent());
        System.out.println("小组长同意");
    }
}

public class Manager extends Handler{
    public Manager() {
        super(Handler.NUM_THREE, Handler.NUM_SEVEN);
    }

    @Override
    protected void handleLeave(LeaveRequest request) {
        System.out.println(request.getName() + "请假" + request.getNum() + "天" +request.getContent());
        System.out.println("部门经理同意");
    }
}

public class GeneralManager extends Handler{
    public GeneralManager() {
        super(Handler.NUM_SEVEN);
    }

    @Override
    protected void handleLeave(LeaveRequest request) {
        System.out.println(request.getName() + "请假" + request.getNum() + "天" +request.getContent());
        System.out.println("总经理同意");
    }
}

测试使用:

public class Client {
    public static void main(String[] args) {
        LeaveRequest request = new LeaveRequest("小花",20,"身体不适");

        GroupLeader groupLeader = new GroupLeader();
        Manager manager = new Manager();
        GeneralManager generalManager = new GeneralManager();

        groupLeader.setNextHandler(manager);
        manager.setNextHandler(generalManager);
        groupLeader.submit(request);
    }
}

总结分析