设计模式之责任链模式
1、类图
责任链模式结构
实例类图
2、创建项目
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3、 PurchaseRequest：采购单类，充当请求类
namespace CoRSample
{
class PurchaseRequest
{
private double amount; //采购金额
private int number; //采购单编号
private string purpose; //采购目的
public PurchaseRequest(double amount, int number, string purpose)
{
this.amount = amount;
this.number = number;
this.purpose = purpose;
}
public double Amount
{
get { return amount; }
set { amount = value; }
}
public int Number
{
get { return number; }
set { number = value; }
}
public string Purpose
{
get { return purpose; }
set { purpose = value; }
}
}
}
4、 Approver：审批者类，充当抽象处理者
namespace CoRSample
{
abstract class Approver
{
protected Approver successor; //定义后继对象
protected string name; //审批者姓名
public Approver(string name)
{
this.name = name;
}
//设置后继者
public void SetSuccessor(Approver successor)
{
this.successor = successor;
}
//抽象请求处理方法
public abstract void ProcessRequest(PurchaseRequest request);
}
}
5、 Director：主任类，充当具体处理者
using System;
namespace CoRSample
{
class Director : Approver
{
public Director(string name) : base(name)
{
}
//具体请求处理方法
public override void ProcessRequest(PurchaseRequest request)
{
if (request.Amount < 50000)
{
Console.WriteLine("主任{0}审批采购单：{1}，金额：{2}元，采购目的：{3}。", this.name, request.Number, request.Amount, request.Purpose); //处理请求
}
else {
this.successor.ProcessRequest(request); //转发请求
}
}
}
}
6、 VicePresident：副董事长类，充当具体处理者
using System;
namespace CoRSample
{
class VicePresident : Approver
{
public VicePresident(string name) : base(name)
{
}
//具体请求处理方法
public override void ProcessRequest(PurchaseRequest request)
{
if (request.Amount < 100000)
{
Console.WriteLine("副董事长{0}审批采购单：{1}，金额：{2}元，采购目的：{3}。", this.name, request.Number, request.Amount, request.Purpose); //处理请求
}
else
{
this.successor.ProcessRequest(request); //转发请求
}
}
}
}
7、 President：董事长类，充当具体处理者
using System;
namespace CoRSample
{
class President : Approver
{
public President(string name) : base(name)
{
}
//具体请求处理方法
public override void ProcessRequest(PurchaseRequest request)
{
if (request.Amount < 500000)
{
Console.WriteLine("董事长{0}审批采购单：{1}，金额：{2}元，采购目的：{3}。", this.name, request.Number, request.Amount, request.Purpose); //处理请求
}
else
{
this.successor.ProcessRequest(request); //转发请求
}
}
}
}
8、 Congress：董事会类，充当具体处理者
using System;
namespace CoRSample
{
class Congress : Approver
{
public Congress(string name) : base(name)
{
}
//具体请求处理方法
public override void ProcessRequest(PurchaseRequest request)
{
Console.WriteLine("召开董事会审批采购单：{0}，金额：{1}元，采购目的：{2}。",request.Number, request.Amount, request.Purpose); //处理请求
}
}
}
9、 Program：客户端测试类
using System;
namespace CoRSample
{
class Program
{
static void Main(string[] args)
{
Approver wjzhang, gyang, jguo, meeting;
//Approver rhuang;
//rhuang = new Manager("黄蓉");
wjzhang = new Director("张无忌");
gyang = new VicePresident("杨过");
jguo = new President("郭靖");
meeting = new Congress("董事会");
//创建职责链
wjzhang.SetSuccessor(gyang);
gyang.SetSuccessor(jguo);
jguo.SetSuccessor(meeting);
//wjzhang.SetSuccessor(rhuang); //将“黄蓉”作为“张无忌”的下家
//rhuang.SetSuccessor(gyang); //将“杨过”作为“黄蓉”的下家
//gyang.SetSuccessor(jguo);
//jguo.SetSuccessor(meeting);
//创建采购单
PurchaseRequest pr1 = new PurchaseRequest(45000, 10001, "购买倚天剑");
wjzhang.ProcessRequest(pr1);
PurchaseRequest pr2 = new PurchaseRequest(60000, 10002, "购买《葵花宝典》");
wjzhang.ProcessRequest(pr2);
PurchaseRequest pr3 = new PurchaseRequest(160000, 10003, "购买《金刚经》");
wjzhang.ProcessRequest(pr3);
PurchaseRequest pr4 = new PurchaseRequest(800000, 10004, "购买桃花岛");
wjzhang.ProcessRequest(pr4);
Console.Read();
}
}
}
10、 结果及分析，编译并运行程序，输出结果如下：
