责任链模式

按照我的理解，责任链就是每个对象都含有自己下一个对象的引用.

当一个对象请求的时候，会根据要求找到正确的对象.

public interface ILeave {
    String getName();//请假人姓名
    int getNum();//请假天数
    String getContent();//请假条内容
}

请假条抽象

public class Leave implements ILeave{
    private String name;//姓名
    private int num;//请假天数
    private String content;//请假内容

    public Leave(String name, int num, String content) {
        this.name = name;
        this.num = num;
        this.content = content;
    }

    public String getName() {
        return name;
    }

    public int getNum() {
        return num;
    }

    public String getContent() {
        return content;
    }
}

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;

    //该领导处理的请假天数区间
    private int numStart = 0;
    private int numEnd = 0;

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

    //设置请假天数范围 上不封顶
    public Handler(int numStart) {
        this.numStart = numStart;
    }

    //设置请假天数范围
    public Handler(int numStart, int numEnd) {
        this.numStart = numStart;
        this.numEnd = numEnd;
    }

    //设置上级领导
    public void setNextHandler(Handler nextHandler){
        this.nextHandler = nextHandler;
    }

    //提交请假条
    public final void submit(ILeave leave){
        if(0 == this.numStart){
            return;
        }

        //如果请假天数达到该领导者的处理要求
        if(leave.getNum() >= this.numStart){
            this.handleLeave(leave);

            //如果还有上级 并且请假天数超过了当前领导的处理范围
            if(null != this.nextHandler && leave.getNum() > numEnd){
                this.nextHandler.submit(leave);//继续提交
            }
        }
    }

    //各级领导处理请假条方法
    protected abstract void handleLeave(ILeave leave);
}

处理者抽象

public class GroupLeader extends Handler {

    public GroupLeader() {
        //小组长处理1-3天的请假
        super(Handler.NUM_ONE, Handler.NUM_THREE);
    }

    @Override
    protected void handleLeave(ILeave leave) {
        System.out.println(leave.getName() + "请假" + leave.getNum() + "天," + leave.getContent() + "。");
        System.out.println("小组长审批：同意。");
    }
}

小组长

public class Manager extends Handler {
    public Manager() {
        //部门经理处理3-7天的请假
        super(Handler.NUM_THREE, Handler.NUM_SEVEN);
    }

    @Override
    protected void handleLeave(ILeave leave) {
        System.out.println(leave.getName() + "请假" + leave.getNum() + "天," + leave.getContent() + "。");
        System.out.println("部门经理审批：同意。");
    }
}

部门经理

public class BigManager extends Handler {
    public BigManager() {
        //部门经理处理7天以上的请假
        super(Handler.NUM_SEVEN);
    }

    @Override
    protected void handleLeave(ILeave leave) {
        System.out.println(leave.getName() + "请假" + leave.getNum() + "天," + leave.getContent() + "。");
        System.out.println("总经理审批：同意。");
    }
}

总经理

public static void main(String[] args) {
        //请假条来一张
        ILeave leave = new Leave("小花",5,"身体不适");

        //各位领导
        Handler groupLeader = new GroupLeader();
        Handler manager = new Manager();
        Handler bigManager = new BigManager();

        groupLeader.setNextHandler(manager);//小组长的领导是部门经理
        manager.setNextHandler(bigManager);//部门经理的领导是总经理
        //之所以在这里设置上级领导，是因为可以根据实际需求来更改设置，如果实战中上级领导人都是固定的，则可以移到领导实现类中。

        //提交申请
        groupLeader.submit(leave);
    }

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