【设计模式】加薪非要老总批 --- 职责链模式

一，概述

定义：使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这个对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为之。

优点：客户提出请求时，请求时沿链传递直至有一个ConcreteHandler对象负责处理它

二，职责链基本代码

#include <iostream>
using namespace std; 

class Handler
{
        protected:
		 static  Handler *successor;

        public:
		 void SetSuccessor(Handler *successor)
        {
            this->successor = successor;
        }

        virtual void HandleRequest(int request)
        {
        	
		} 
}; 
Handler* Handler::successor=NULL; //必须是static 变量才能在全局初始化 

    class ConcreteHandler1 :public Handler
    {
        public: 
		  void HandleRequest(int request)
        {
            if (request >= 0 && request < 10)
            {
                cout<<"ConcreteHandler1"<<"处理请求"<<request<<endl;
            }
            else if (successor != NULL)
            {
                successor->HandleRequest(request);
            }
        }
    }; 

    class ConcreteHandler2 :public Handler
    {
        public:
	        void HandleRequest(int request)
           {
            if (request >= 10 && request < 20)
            {
                cout<<"ConcreteHandler2"<<"处理请求"<<request<<endl;
            }
            else if (successor != NULL)
            {
                successor->HandleRequest(request);
            }
        }
    }; 

    class ConcreteHandler3 :public Handler
    {
        public:
		 void HandleRequest(int request)
        {
            if (request >= 20 && request < 30)
            {
                cout<<"ConcreteHandler3"<<"处理请求"<<request<<endl;
            }
            else if (successor != NULL)
            {
                successor->HandleRequest(request);
            }
        }
    }; 
int main()
{
            Handler *h1 = new ConcreteHandler1();
            Handler *h2 = new ConcreteHandler2();
            Handler *h3 = new ConcreteHandler3();
            h1->SetSuccessor(h2);//设置下一个 
            h2->SetSuccessor(h3);//设置下一个 

            int request[] = { 2, 5, 14, 22, 18, 3, 27, 20 };

            for(int i=0;i<8;++i)
            {
                h1->HandleRequest(request[i]);
            }
            
            return 0; 

}

三，示例

小菜要求加薪，而加薪的批准需要总经理来批准。经理交给总监，总监交给总经理。

缺点：Manager 类 太长，分支太多。如果要增加项目经理、部门经理等职位的话，需要更改原类，比较麻烦。

#include <iostream>
using namespace std;


 //enum  ManagerLevel{ "经理","总监","总经理"} ManagerLevel; 
 enum  ManagerLevel{ manager,chief_inspector,president} ; 
       //申请
    class Request
    {
        //申请类别
        private:
		 string requestType;
        public:
		 string getRequestType()
        {
            return requestType; 
        }
         void setRequestType(string value) 
		 { 
		    requestType = value; 
         }

        //申请内容
        private:
		 string requestContent;
        public:
		 string getRequestContent()
        {
             return requestContent; 
        }
          void  setRequestContent(string value) 
		  { 
		     requestContent = value; 
		   }
        

        //数量
        private:
		 int number;
        public:
		 int getNumber()
		 {
 			return number;
 		 }
 		 void setNumber(int value)
 		 {
 		 	this->number = value;	
 		 }
    }; 
	 
    //管理者
    class Manager
    {
        
        protected:
		   string name;

        public:
		 Manager(string name)
        {
            this->name = name;
        }

        //得到结果
       void GetResult(ManagerLevel managerLevel, Request request)
        {
            if (managerLevel == manager)
            {
                if (request.getRequestType() == "请假" && request.getNumber() <= 2)
                {
                    //Console.WriteLine("{0}:{1} 数量{2} 被批准", name, request.RequestContent, request.Number);
                    cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
                }
                else
                {
                	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"我无权处理"<<endl; 
                    //Console.WriteLine("{0}:{1} 数量{2} 我无权处理", name, request.RequestContent, request.Number);
                }

            }
            else if (managerLevel ==chief_inspector)
            {
                if (request.getRequestType() == "请假" && request.getNumber() <= 5)
                {
                	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
                    //Console.WriteLine("{0}:{1} 数量{2} 被批准", name, request.RequestContent, request.Number);
                }
                else
                {
                	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"我无权处理"<<endl; 
                    //Console.WriteLine("{0}:{1} 数量{2} 我无权处理", name, request.RequestContent, request.Number);
                }
            }
            else if (managerLevel == president)
            {
                if (request.getRequestType() == "请假")
                {
                	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
                    //Console.WriteLine("{0}:{1} 数量{2} 被批准", name, request.RequestContent, request.Number);
                }
                else if (request.getRequestType() == "加薪" && request.getNumber() <= 500)
                {
                	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
                   // Console.WriteLine("{0}:{1} 数量{2} 被批准", name, request.RequestContent, request.Number);
                }
                else if (request.getRequestType() == "加薪" && request.getNumber() > 500)
                {
                	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
                   // Console.WriteLine("{0}:{1} 数量{2} 再说吧", name, request.RequestContent, request.Number);
                }
            }

        }
    }; 


    
       int main()
        {

            Manager *jinli = new Manager("金利");
            Manager *zongjian = new Manager("宗剑");
            Manager *zhongjingli = new Manager("钟精励");

            Request *request = new Request();
            request->setRequestType("加薪");
            request->setRequestContent("小菜请求加薪");
            request->setNumber(1000);

            jinli->GetResult(manager, *request);
            zongjian->GetResult(chief_inspector, *request);
            zhongjingli->GetResult(president, *request);

            Request *request2 = new Request();
            request2->setRequestType("请假");
            request2->setRequestContent("小菜请假");
            request2->setNumber(3);

            jinli->GetResult(manager, *request2);
            zongjian->GetResult(chief_inspector, *request2);
            zhongjingli->GetResult(president, *request2);
            
            return 0; 

        }
        

2）改进后的代码

说明：C++中不可以直接声明类的对象，但是可以直接声明类的指针。

#include <iostream>
using namespace std;


 //enum  ManagerLevel{ "经理","总监","总经理"} ManagerLevel; 
 enum  ManagerLevel{ manager,chief_inspector,president} ; 
       //申请
    class Request
    {
        //申请类别
        private:
		 string requestType;
        public:
		 string getRequestType()
        {
            return requestType; 
        }
         void setRequestType(string value) 
		 { 
		    requestType = value; 
         }

        //申请内容
        private:
		 string requestContent;
        public:
		 string getRequestContent()
        {
             return requestContent; 
        }
          void  setRequestContent(string value) 
		  { 
		     requestContent = value; 
		   }
        

        //数量
        private:
		 int number;
        public:
		 int getNumber()
		 {
 			return number;
 		 }
 		 void setNumber(int value)
 		 {
 		 	this->number = value;	
 		 }
    }; 



    //管理者
  class Manager
  {
        protected:
		 string name;
        //管理者的上级
         Manager *superior;

        public:
		 Manager(string name)
        {
            this->name = name;
        }

        //设置管理者的上级
        void SetSuperior(Manager *superior)
        {
            this->superior = superior;
        }

        //申请请求
        virtual void RequestApplications(Request request)
        {
		} 
    }; 

    //经理
    class CommonManager :public Manager
    {
        public:
		 CommonManager(string name)
            : Manager(name)
        { }
         void RequestApplications(Request request)
        {

            if (request.getRequestType() == "请假" && request.getNumber() <= 2)
            {
                cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
            }
            else
            {
                if (superior != NULL)
                    superior->RequestApplications(request);
            }

        }
    }; 

    //总监
    class Majordomo :public Manager
    {
        public: 
		 Majordomo(string name)
            : Manager(name)
        { }
         void RequestApplications(Request request)
        {

            if (request.getRequestType() == "请假" && request.getNumber() <= 5)
            {
                cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
            }
            else
            {
                if (superior != NULL)
                    superior->RequestApplications(request);
            }

        }
    }; 

    //总经理
    class GeneralManager :public Manager
    {
        public:
		 GeneralManager(string name): Manager(name)
        { }
        void RequestApplications(Request request)
        {

            if (request.getRequestType() == "请假")
            {
                cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
            }
            else if (request.getRequestType() == "加薪" && request.getNumber() <= 500)
            {
               cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"被批准"<<endl; 
            }
            else if (request.getRequestType() == "加薪" && request.getNumber() > 500)
            {
            	cout<<name<< request.getRequestContent()<<"数量"<< request.getNumber()<<"再说吧"<<endl; 
               
            }
        }
    }; 

        int main()
        {

            CommonManager *jinli = new CommonManager("金利");
            Majordomo *zongjian = new Majordomo("宗剑");
            GeneralManager *zhongjingli = new GeneralManager("钟精励");
            jinli->SetSuperior(zongjian);
            zongjian->SetSuperior(zhongjingli);

            Request *request = new Request();
            request->setRequestType("请假");
            request->setRequestContent("小菜请假");
            request->setNumber(1);
            jinli->RequestApplications(*request);

            Request *request2 = new Request();
            request2->setRequestType("请假");
            request2->setRequestContent("小菜请假");
            request2->setNumber(4);
            jinli->RequestApplications(*request2);

            Request *request3 = new Request();
            request3->setRequestType("加薪");
            request3->setRequestContent("小菜请求加薪");
            request3->setNumber(500);
            jinli->RequestApplications(*request3);

            Request *request4 = new Request();
            request4->setRequestType("加薪");
            request4->setRequestContent("小菜请求加薪");
            request4->setNumber(1000);
            jinli->RequestApplications(*request4);

           return 0; 

        }