设计模式C++学习笔记之十七（Chain of Responsibility责任链模式）
17.1.解释
概念：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。将这些对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止。
main()，客户
IWomen，发出请求者接口
CWomen，请求者实现类
CHandler，处理请求抽象类
CFather，处理请求实现类，责任链之一
CHusband，处理请求实现类，责任链之二
CSon，处理请求实现类，责任链之三
说明：CHandler抽象类负责聚合责任链之中的其它处理对象，用SetNext来建立这个责任链。HandleMessage在处理请求时，会判断是否是自己要处理的请求，如果是则直接处理。如果不是，则查找下一个责任链上的处理对象，找到了则由下一个处理。
//IWomen.h
#pragma once
#include <iostream>
using std::string;
class IWomen
{
public:
IWomen(void)
{
}
virtual ~IWomen(void)
{
}
virtual int GetType() = 0;
virtual string GetRequest() = 0;
};
//Women.h
#pragma once
#include "iwomen.h"
#include <iostream>
using std::string;
class CWomen :
public IWomen
{
public:
CWomen(int _type, string _request);
~CWomen(void);
int GetType();
string GetRequest();
private:
int m_type;
string m_request;
};
//Women.cpp
#include "StdAfx.h"
#include "Women.h"
CWomen::CWomen( int _type, string _request )
{
this->m_type = _type;
switch (this->m_type)
{
case 1:
this->m_request.append("女儿的请求是：");
this->m_request.append(_request);
break;
case 2:
this->m_request.append("妻子的请求是：");
this->m_request.append(_request);
break;
case 3:
this->m_request.append("母亲的请求是：");
this->m_request.append(_request);
break;
}
}
CWomen::~CWomen(void)
{
}
int CWomen::GetType()
{
return m_type;
}
string CWomen::GetRequest()
{
return m_request;
}
//Handler.h
#pragma once
#include "IWomen.h"
class CHandler
{
public:
CHandler(int _level);
virtual ~CHandler(void);
void HandleMessage(IWomen *pwomen);
void SetNext(CHandler *phandler);
virtual void Response(IWomen *pwomen) = 0;
private:
int m_level;
CHandler *m_pNextHandler;
};
//Handler.cpp
#include "StdAfx.h"
#include "Handler.h"
#include <iostream>
using std::cout;
using std::endl;
CHandler::CHandler(int _level ) : m_level(_level)
{
m_pNextHandler = NULL;
}
CHandler::~CHandler(void)
{
}
void CHandler::HandleMessage( IWomen *pwomen )
{
if (pwomen->GetType() == this->m_level)
{
this->Response(pwomen);
}
else
{
if(this->m_pNextHandler != NULL)
this->m_pNextHandler->HandleMessage(pwomen);
else
cout << "----------没地方请示了，不做处理！----------" << endl;
}
}
void CHandler::SetNext( CHandler *phandler )
{
m_pNextHandler = phandler;
}
//Father.h
#pragma once
#include "handler.h"
#include "IWomen.h"
class CFather :
public CHandler
{
public:
CFather(void);
~CFather(void);
void Response(IWomen *pwomen);
};
//Father.cpp
#include "StdAfx.h"
#include "Father.h"
#include <iostream>
using std::cout;
using std::endl;
CFather::CFather(void) : CHandler(1)
{
}
CFather::~CFather(void)
{
}
void CFather::Response( IWomen *pwomen )
{
cout << "女儿向父亲请示：" << endl;
cout << pwomen->GetRequest().c_str() << endl;
cout << "父亲的答复是：同意" << endl;
}
//Husband.h
#pragma once
#include "handler.h"
#include "IWomen.h"
class CHusband :
public CHandler
{
public:
CHusband(void);
~CHusband(void);
void Response(IWomen *pwomen);
};
//Husband.cpp
#include "StdAfx.h"
#include "Husband.h"
#include <iostream>
using std::cout;
using std::endl;
CHusband::CHusband(void) : CHandler(2)
{
}
CHusband::~CHusband(void)
{
}
void CHusband::Response( IWomen *pwomen )
{
cout << "妻子向丈夫请示：" << endl;
cout << pwomen->GetRequest().c_str() << endl;
cout << "丈夫的答复是：同意" << endl;
}
//Son.h
#pragma once
#include "handler.h"
#include "IWomen.h"
class CSon :
public CHandler
{
public:
CSon(void);
~CSon(void);
void Response(IWomen *pwomen);
};
//Son.cpp
#include "StdAfx.h"
#include "Son.h"
#include <iostream>
using std::cout;
using std::endl;
CSon::CSon(void) : CHandler(3)
{
}
CSon::~CSon(void)
{
}
void CSon::Response( IWomen *pwomen )
{
cout << "母亲向儿子请示：" << endl;
cout << pwomen->GetRequest().c_str() << endl;
cout << "儿子的答复是：同意" << endl;
}
// ChainofResponsibility.cpp
#include "stdafx.h"
#include "INormalWomen.h"
#include "NormalWomen.h"
#include "INormalHandler.h"
#include "NormalFather.h"
#include "NormalHusband.h"
#include "NormalSon.h"
#include "IWomen.h"
#include "Women.h"
#include "Handler.h"
#include "Father.h"
#include "Husband.h"
#include "Son.h"
#include <iostream>
using std::cout;
using std::endl;
void DoIt()
{
cout << "----------原来的处理方式----------" << endl;
//INormalWomen.h, NormalWomen.h, INormalHandler.h, NormalFather.h, NormalHusband.h, NormalSon.h
INormalWomen *pwomen = new CNormalWomen(1, "我要出去逛街");
INormalHandler *pfather = new CNormalFather();
INormalHandler *phusband = new CNormalHusband();
INormalHandler *pson = new CNormalSon();
if (pwomen->GetType() == 1)
{
cout << "女儿向父亲请示：" << endl;
pfather->HandleMessage(pwomen);
}
else if (pwomen->GetType() == 2)
{
cout << "妻子向丈夫请示：" << endl;
phusband->HandleMessage(pwomen);
}
else if (pwomen->GetType() == 3)
{
cout << "母亲向儿子请示：" << endl;
pson->HandleMessage(pwomen);
}
else
{
//什么也不做
}
delete pwomen;
delete pfather;
delete phusband;
delete pson;
}
void DoNew()
{
cout << "----------使用模式后的处理方式----------" << endl;
//Handler.h, Handler.cpp, IWomen.h, Women.h, Women.cpp, Father.h, Father,cpp, Husband.h, Husband.cpp, Son.h, Son.cpp
IWomen *pwomen1 = new CWomen(1, "我要出去逛街");
IWomen *pwomen2 = new CWomen(2, "我要出去吃饭");
IWomen *pwomen3 = new CWomen(3, "我也要出去吃饭");
IWomen *pwomen4 = new CWomen(4, "我也要出去逛街");
CHandler *pfather = new CFather();
CHandler *phusband = new CHusband();
CHandler *pson = new CSon();
pfather->SetNext(phusband);
phusband->SetNext(pson);
pfather->HandleMessage(pwomen1);
pfather->HandleMessage(pwomen2);
pfather->HandleMessage(pwomen3);
pfather->HandleMessage(pwomen4);
delete pfather;
delete phusband;
delete pson;
delete pwomen1;
delete pwomen2;
delete pwomen3;
delete pwomen4;
}
int _tmain(int argc, _TCHAR* argv[])
{
//反面
DoIt();
//要实现逻辑判断，即女性的请求先发送到父亲类，父亲类一看是自己要处理的，就回应进行处理。如果女儿已经出嫁了，那就把这个请求转发到女婿类来处理。依此类推，形成了一个责任链。
DoNew();
return 0;
}
