设计模式--职责链模式

实验15：职责链模式

本次实验属于模仿型实验，通过本次实验学生将掌握以下内容： 

1、理解职责链模式的动机，掌握该模式的结构；

2、能够利用职责链模式解决实际问题。

[实验任务]：财务审批

某物资管理系统中物资采购需要分级审批，主任可以审批1万元及以下的采购单，部门经理可以审批5万元及以下的采购单，副总经理可以审批10万元及以下的采购单，总经理可以审批20万元及以下的采购单，20万元以上的采购单需要开职工大会确定。现用职责链模式设计该系统。

类图

源代码

public abstract class Leader
{
    protected String name;
    protected Leader successor;

    public Leader(String name)
    {
        this.name = name;
    }

    public void setSuccessor(Leader successor)
    {
        this.successor = successor;
    }

    public abstract void handleRequest(PurchaseRequest request);
}

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

    @Override
    public void handleRequest(PurchaseRequest request)
    {
        if (request.getMoney() <= 50000)
        {
            System.out.println("部门经理" + name + "审批采购单，采购单单号为：" + request.getId() + ",金额为：" + request.getMoney() + "元");
        } else
        {
            if (this.successor != null)
            {
                this.successor.handleRequest(request);
            }
        }
    }
}

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

    @Override
    public void handleRequest(PurchaseRequest request)
    {
        if (request.getMoney() <= 10000)
        {
            System.out.println("主任" + name + "审批采购单，采购单单号为：" + request.getId() + ",金额为：" + request.getMoney() + "元");
        } else
        {
            if (this.successor != null)
            {
                this.successor.handleRequest(request);
            }
        }
    }
}

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

    @Override
    public void handleRequest(PurchaseRequest request)
    {
        if (request.getMoney() <= 200000)
        {
            System.out.println("总经理" + name + "审批采购单，采购单单号为：" + request.getId() + ",金额为：" + request.getMoney() + "元");
        } else
        {
            System.out.println("采购单单号为：" + request.getId() + ",金额为：" +request.getMoney() + "元，金额太大，需开职工大会确定是否审批通过");
        }
    }
}

public class Manager extends Leader
{

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

    @Override
    public void handleRequest(PurchaseRequest request)
    {
        if (request.getMoney() <= 100000)
        {
            System.out.println("副总经理" + name + "审批采购单，采购单单号为：" + request.getId() + ",金额为：" + request.getMoney() + "元");
        } else
        {
            if (this.successor != null)
            {
                this.successor.handleRequest(request);
            }
        }
    }
}

public class PurchaseRequest
{
    private int money;
    private int id;

    public PurchaseRequest(int id, int money)
    {
        this.id = id;
        this.money = money;
    }

    public int getMoney()
    {
        return money;
    }

    public void setMoney(int money)
    {
        this.money = money;
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }
}

public class Client
{
    public static void main(String[] args)
    {
        Leader objDirector, objDepartmentManager, objManager, objGeneralManager;

        objDirector = new Director("张三");
        objDepartmentManager = new DepartmentManager("李四");
        objManager = new Manager("王五");
        objGeneralManager = new GeneralManager("赵六");

        objDirector.setSuccessor(objDepartmentManager);
        objDepartmentManager.setSuccessor(objManager);
        objManager.setSuccessor(objGeneralManager);

        PurchaseRequest pr1=new PurchaseRequest(1001,10000);
        objDirector.handleRequest(pr1);

        PurchaseRequest pr2=new PurchaseRequest(1002,50000);
        objDirector.handleRequest(pr2);

        PurchaseRequest pr3=new PurchaseRequest(1003,100000);
        objDirector.handleRequest(pr3);

        PurchaseRequest pr4=new PurchaseRequest(1004,200000);
        objDirector.handleRequest(pr4);

        PurchaseRequest pr5=new PurchaseRequest(1005,200001);
        objDirector.handleRequest(pr5);
    }
}

运行效果