2024.11.14

设计模式实验十五

软件设计                  石家庄铁道大学信息学院

 

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；

// PurchaseRequest.java

public class PurchaseRequest {

    private double amount;

    private String purpose;

 

    public PurchaseRequest(double amount, String purpose) {

        this.amount = amount;

        this.purpose = purpose;

    }

 

    public double getAmount() {

        return amount;

    }

 

    public String getPurpose() {

        return purpose;

    }

}

 

// Approver.java

abstract class Approver {

    protected Approver nextApprover;

    protected String position;

 

    public Approver(String position) {

        this.position = position;

    }

 

    public void setNextApprover(Approver nextApprover) {

        this.nextApprover = nextApprover;

    }

 

    public abstract void processRequest(PurchaseRequest request);

}

 

// Director.java

class Director extends Approver {

    public Director() {

        super("Director");

    }

 

    @Override

    public void processRequest(PurchaseRequest request) {

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

            System.out.println(position + " approved the request for " + request.getPurpose());

        } else if (nextApprover != null) {

            nextApprover.processRequest(request);

        }

    }

}

 

// DepartmentManager.java

class DepartmentManager extends Approver {

    public DepartmentManager() {

        super("Department Manager");

    }

 

    @Override

    public void processRequest(PurchaseRequest request) {

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

            System.out.println(position + " approved the request for " + request.getPurpose());

        } else if (nextApprover != null) {

            nextApprover.processRequest(request);

        }

    }

}

 

// ViceManager.java

class ViceManager extends Approver {

    public ViceManager() {

        super("Vice Manager");

    }

 

    @Override

    public void processRequest(PurchaseRequest request) {

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

            System.out.println(position + " approved the request for " + request.getPurpose());

        } else if (nextApprover != null) {

            nextApprover.processRequest(request);

        }

    }

}

 

// GeneralManager.java

class GeneralManager extends Approver {

    public GeneralManager() {

        super("General Manager");

    }

 

    @Override

    public void processRequest(PurchaseRequest request) {

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

            System.out.println(position + " approved the request for " + request.getPurpose());

        } else {

            System.out.println("Request for " + request.getPurpose() + " requires a staff meeting for approval.");

        }

    }

}

 

// Client.java

public class Client {

    public static void main(String[] args) {

        // Create approvers

        Approver director = new Director();

        Approver departmentManager = new DepartmentManager();

        Approver viceManager = new ViceManager();

        Approver generalManager = new GeneralManager();

 

        // Set up the chain of responsibility

        director.setNextApprover(departmentManager);

        departmentManager.setNextApprover(viceManager);

        viceManager.setNextApprover(generalManager);

 

        // Create some purchase requests

        PurchaseRequest request1 = new PurchaseRequest(5000, "Office Supplies");

        PurchaseRequest request2 = new PurchaseRequest(30000, "New Desks");

        PurchaseRequest request3 = new PurchaseRequest(70000, "Computer Equipment");

        PurchaseRequest request4 = new PurchaseRequest(150000, "Renovation");

        PurchaseRequest request5 = new PurchaseRequest(250000, "Building Expansion");

 

        // Process each request

        director.processRequest(request1);

        director.processRequest(request2);

        director.processRequest(request3);

        director.processRequest(request4);

        director.processRequest(request5);

    }

}

3. 注意编程规范。