24.11.30

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。

[实验任务一]：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。

实验要求：

1. 提交类图；

2. 提交源代码；

3. 注意编程规范。

 

1. 类图:

 

 

1. 源代码:

// 抽象处理者

abstract class Approver {

    protected Approver nextApprover;  // 下一个处理者

 

    public void setNextApprover(Approver nextApprover) {

        this.nextApprover = nextApprover;

    }

 

    public abstract void processRequest(PurchaseRequest request);

}

 

// 采购请求类

class PurchaseRequest {

    private double amount;  // 采购金额

    private String purpose; // 采购目的

 

    public PurchaseRequest(double amount, String purpose) {

        this.amount = amount;

        this.purpose = purpose;

    }

 

    public double getAmount() {

        return amount;

    }

 

    public String getPurpose() {

        return purpose;

    }

}

 

// 具体处理者：主任

class Director extends Approver {

    @Override

    public void processRequest(PurchaseRequest request) {

        if (request.getAmount() <= 10000) {

            System.out.println("主任审批采购单：" + request.getPurpose() + "，金额：" + request.getAmount() + "元");

        } else if (nextApprover != null) {

            nextApprover.processRequest(request);

        }

    }

}

 

// 具体处理者：部门经理

class Manager extends Approver {

    @Override

    public void processRequest(PurchaseRequest request) {

        if (request.getAmount() <= 50000) {

            System.out.println("部门经理审批采购单：" + request.getPurpose() + "，金额：" + request.getAmount() + "元");

        } else if (nextApprover != null) {

            nextApprover.processRequest(request);

        }

    }

}

 

// 具体处理者：副总经理

class VicePresident extends Approver {

    @Override

    public void processRequest(PurchaseRequest request) {

        if (request.getAmount() <= 100000) {

            System.out.println("副总经理审批采购单：" + request.getPurpose() + "，金额：" + request.getAmount() + "元");

        } else if (nextApprover != null) {

            nextApprover.processRequest(request);

        }

    }

}

 

// 具体处理者：总经理

class President extends Approver {

    @Override

    public void processRequest(PurchaseRequest request) {

        if (request.getAmount() <= 200000) {

            System.out.println("总经理审批采购单：" + request.getPurpose() + "，金额：" + request.getAmount() + "元");

        } else {

            System.out.println("金额超过20万元，需要召开职工大会讨论。");

        }

    }

}

 

// 测试类

public class Main {

    public static void main(String[] args) {

        // 创建具体处理者

        Approver director = new Director();

        Approver manager = new Manager();

        Approver vicePresident = new VicePresident();

        Approver president = new President();

 

        // 组装责任链

        director.setNextApprover(manager);

        manager.setNextApprover(vicePresident);

        vicePresident.setNextApprover(president);

 

        // 发起采购请求

        PurchaseRequest request1 = new PurchaseRequest(8000, "购买打印机");

        director.processRequest(request1);

 

        PurchaseRequest request2 = new PurchaseRequest(30000, "购买服务器");

        director.processRequest(request2);

 

        PurchaseRequest request3 = new PurchaseRequest(70000, "员工培训设备");

        director.processRequest(request3);

 

        PurchaseRequest request4 = new PurchaseRequest(150000, "部门装修");

        director.processRequest(request4);

 

        PurchaseRequest request5 = new PurchaseRequest(300000, "新建研发中心");

        director.processRequest(request5);

    }

}