行为型模式----责任链模式

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前沿

• 创建型模式：关注对象的创建过程。
• 结构型模式：关注对象和类的组织。
• 行为型模式：关注系统中对象之间的相互交互，研究系统在运行时对象之间的相互通信和协作，进一步明确对象的职责，共有11种模式。

定义

将能够处理同一类请求的对象连成一条链，所提交的请求沿着链传递，链上的对象逐个判断是否有能力处理该请求，如果能则处理，如果不能则传递给链上的下一个对象。

场景

1、打牌时，轮流出牌。
2、接力赛跑。
3、大学中，奖学金审批。

package GOF.ChainOfResp;

public class LeaveRequest {
    private String empname;
    private int leaveDays;
    private String reason;

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

    public String getEmpname() {
        return empname;
    }

    public int getLeaveDays() {
        return leaveDays;
    }

    public String getReason() {
        return reason;
    }

    public void setEmpname(String empname) {
        this.empname = empname;
    }

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

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

package GOF.ChainOfResp;

public abstract class Leader {
    protected String name;
    protected Leader nextLeader;//责任链后继对象

    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;
    }

    //处理请求的核心业务方法
    public abstract void handleRequst(LeaveRequest  request);
}

package GOF.ChainOfResp;

public class Director extends Leader {


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

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

package GOF.ChainOfResp;

public class Manager extends Leader {
    public Manager(String name) {
        super(name);
    }

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

package GOF.ChainOfResp;

public class GeneralManager extends Leader {
    public GeneralManager(String name) {
        super(name);
    }

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

package GOF.ChainOfResp;

public class Client {
    public static void main(String[] args) {
        Leader a = new Director("张三");
        Leader b = new Manager("李四");
        Leader c = new GeneralManager("王五");

        //责任链对象的关系
        a.setNextLeader(b);
        b.setNextLeader(c);

        //开始操作
        LeaveRequest reql = new LeaveRequest("TOM",9,"回英国老家！");
        a.handleRequst(reql);
    }
}