11.13日报

今天完成了设计模式的实验十五，以下为今日实验内容：

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；

1. // 采购请求类
   class PurchaseRequest {
       private double amount;
       private Approver approver;
   
       public PurchaseRequest(double amount) {
           this.amount = amount;
       }
   
       public void setApprover(Approver approver) {
           this.approver = approver;
       }
   
       public Approver getApprover() {
           return approver;
       }
   
       public double getAmount() {
           return amount;
       }
   
       public void requestApproval() {
           approver.requestApproval(this);
       }
   }
   
   // 审批人抽象类
   abstract class Approver {
       protected Approver successor;
   
       public void setSuccessor(Approver successor) {
           this.successor = successor;
       }
   
       public abstract String requestApproval(PurchaseRequest request);
   }
   
   // 主任类
   class Director extends Approver {
       @Override
       public String requestApproval(PurchaseRequest request) {
           if (request.getAmount() <= 10000) {
               return "Director approved the request.";
           } else if (successor != null) {
               return successor.requestApproval(request);
           } else {
               return "Request denied.";
           }
       }
   }
   
   // 部门经理类
   class DepartmentManager extends Approver {
       @Override
       public String requestApproval(PurchaseRequest request) {
           if (request.getAmount() <= 50000) {
               return "Department Manager approved the request.";
           } else if (successor != null) {
               return successor.requestApproval(request);
           } else {
               return "Request denied.";
           }
       }
   }
   
   // 副总经理类
   class DeputyGeneralManager extends Approver {
       @Override
       public String requestApproval(PurchaseRequest request) {
           if (request.getAmount() <= 100000) {
               return "Deputy General Manager approved the request.";
           } else if (successor != null) {
               return successor.requestApproval(request);
           } else {
               return "Request denied.";
           }
       }
   }
   
   // 总经理类
   class GeneralManager extends Approver {
       @Override
       public String requestApproval(PurchaseRequest request) {
           if (request.getAmount() <= 200000) {
               return "General Manager approved the request.";
           } else if (successor != null) {
               return successor.requestApproval(request);
           } else {
               return "Request denied.";
           }
       }
   }
   
   // 职工大会类
   class StaffMeeting extends Approver {
       @Override
       public String requestApproval(PurchaseRequest request) {
           return "Staff meeting approved the request.";
       }
   }
   
   // 客户端代码
   public class Client {
       public static void main(String[] args) {
           Approver director = new Director();
           Approver departmentManager = new DepartmentManager();
           Approver deputyGeneralManager = new DeputyGeneralManager();
           Approver generalManager = new GeneralManager();
           Approver staffMeeting = new StaffMeeting();
   
           director.setSuccessor(departmentManager);
           departmentManager.setSuccessor(deputyGeneralManager);
           deputyGeneralManager.setSuccessor(generalManager);
           generalManager.setSuccessor(staffMeeting);
   
           PurchaseRequest request1 = new PurchaseRequest(5000);
           request1.setApprover(director);
           request1.requestApproval(); // Director approved the request.
   
           PurchaseRequest request2 = new PurchaseRequest(30000);
           request2.setApprover(director);
           request2.requestApproval(); // Department Manager approved the request.
   
           PurchaseRequest request3 = new PurchaseRequest(150000);
           request3.setApprover(director);
           request3.requestApproval(); // Deputy General Manager approved the request.
   
           PurchaseRequest request4 = new PurchaseRequest(250000);
           request4.setApprover(director);
           request4.requestApproval(); // Staff meeting approved the request.
       }
   }

 

3. 注意编程规范。