設計模式C++學習筆記之五（Factory MethodFactory 方法模式）

Factory 方法模式的意義是定義一個建立產品對象的工廠介面，將實際建立工作延遲到子類當中。核心工廠類不再負責產品的建立，這樣核心類成為一個抽象工廠角色，僅負責具體工廠子類必須實現的介面，這樣進一步抽象化的好處是使得Factory 方法模式可以使系統在不修改具體工廠角色的情況下引進新的產品。這個例子更詳細的內容及說明可以參考原作者部落格：cbf4life.cnblogs.com。貼代碼了。

5.1.解釋

main()，女媧

IHuman，產品介面

CYellowHuman，產品之一

CWhiteHuman，產品之二

CBlackHuman，產品之三

IHumanFactory，工廠介面

CYellowHumanFactory，工廠之一

CWhiteHumanFactory，工廠之二

CBlackHumanFactory，工廠之三

看代碼：

//IHuman.h

#pragma once
class IHuman
{
public:
    IHuman(void)
    {
    }
    virtual ~IHuman(void)
    {
    }
    virtual void Laugh() = 0;
    virtual void Cry() = 0;
    virtual void Talk() = 0;
};

//YellowHuman.h

#pragma once
#include "ihuman.h"
class CYellowHuman :
    public IHuman
{
public:
    CYellowHuman(void);
    ~CYellowHuman(void);
    void Laugh();
    void Cry();
    void Talk();
};

//YellowHuman.cpp

#include "StdAfx.h"
#include "YellowHuman.h"
#include <iostream>
using std::cout;
using std::endl;
CYellowHuman::CYellowHuman(void)
{
}
CYellowHuman::~CYellowHuman(void)
{
}
void CYellowHuman::Cry()
{
    cout << "黃色人種會哭" << endl;
}
void CYellowHuman::Laugh()
{
    cout << "黃色人種會大笑，幸福呀！" << endl;
}
void CYellowHuman::Talk()
{
    cout << "黃色人種會說話，一般說的都是雙位元組" << endl;
}

//WhiteHuman.h

#pragma once
#include "ihuman.h"
class CWhiteHuman :
    public IHuman
{
public:
    CWhiteHuman(void);
    ~CWhiteHuman(void);
    void Laugh();
    void Cry();
    void Talk();
};

//WhiteHuman.cpp

#include "StdAfx.h"
#include "WhiteHuman.h"
#include <iostream>
using std::cout;
using std::endl;
CWhiteHuman::CWhiteHuman(void)
{
}
CWhiteHuman::~CWhiteHuman(void)
{
}
void CWhiteHuman::Cry()
{
    cout << "白色人種會哭" << endl;
}
void CWhiteHuman::Laugh()
{
    cout << "白色人種會大笑，侵略的笑聲" << endl;
}
void CWhiteHuman::Talk()
{
    cout << "白色人種會說話，一般都是單位元組" << endl;
}

//BlackHuman.h

#pragma once
#include "ihuman.h"
class CBlackHuman :
    public IHuman
{
public:
    CBlackHuman(void);
    ~CBlackHuman(void);
    void Laugh();
    void Cry();
    void Talk();
};

//BlackHuman.cpp

#include "StdAfx.h"
#include "BlackHuman.h"
#include <iostream>
using std::cout;
using std::endl;
CBlackHuman::CBlackHuman(void)
{
}
CBlackHuman::~CBlackHuman(void)
{
}
void CBlackHuman::Cry()
{
    cout << "黑人會哭" << endl;
}
void CBlackHuman::Laugh()
{
    cout << "黑人會笑" << endl;
}
void CBlackHuman::Talk()
{
    cout << "黑人可以說話，一般人聽不懂" << endl;
}

//IHumanFactory.h

#pragma once
#include "IHuman.h"
class IHumanFactory
{
public:
    IHumanFactory(void)
    {
    }
    virtual ~IHumanFactory(void)
    {
    }
    virtual IHuman * CreateHuman() = 0;
};
//YellowHuman.h

#pragma once
#include "ihumanfactory.h"
class CYellowHumanFactory :
    public IHumanFactory
{
public:
    CYellowHumanFactory(void);
    ~CYellowHumanFactory(void);
    virtual IHuman * CreateHuman(void);
};

//YellowHumanFactory.cpp

#include "StdAfx.h"
#include "YellowHumanFactory.h"
#include "YellowHuman.h"
CYellowHumanFactory::CYellowHumanFactory(void)
{
}
CYellowHumanFactory::~CYellowHumanFactory(void)
{
}
IHuman * CYellowHumanFactory::CreateHuman( void )
{
    return new CYellowHuman();
}
//WhiteHuman.h

#pragma once
#include "ihumanfactory.h"
class CWhiteHumanFactory :
    public IHumanFactory
{
public:
    CWhiteHumanFactory(void);
    ~CWhiteHumanFactory(void);
    virtual IHuman * CreateHuman(void);
};

//WhiteHumanFactory.cpp

#include "StdAfx.h"
#include "WhiteHumanFactory.h"
#include "WhiteHuman.h"
CWhiteHumanFactory::CWhiteHumanFactory(void)
{
}
CWhiteHumanFactory::~CWhiteHumanFactory(void)
{
}
IHuman * CWhiteHumanFactory::CreateHuman( void )
{
    return new CWhiteHuman();
}
//BlackHuman.h

#pragma once
#include "ihumanfactory.h"
class CBlackHumanFactory :
    public IHumanFactory
{
public:
    CBlackHumanFactory(void);
    ~CBlackHumanFactory(void);
    virtual IHuman * CreateHuman();
};
//BlackHumanFactory.cpp

#include "StdAfx.h"
#include "BlackHumanFactory.h"
#include "BlackHuman.h"
CBlackHumanFactory::CBlackHumanFactory(void)
{
}
CBlackHumanFactory::~CBlackHumanFactory(void)
{
}
IHuman * CBlackHumanFactory::CreateHuman()
{
    return new CBlackHuman();
}

//FactoryMethod.cpp

// FactoryMethod.cpp : 定義控制台應用程式的進入點。
//
#include "stdafx.h"
#include "IHuman.h"
#include "YellowHuman.h"
#include "WhiteHuman.h"
#include "BlackHuman.h"
#include "SimpleHumanFactory.h"
#include "StandardHumanFactory.h"
#include "IHumanFactory.h"
#include "YellowHumanFactory.h"
#include "WhiteHumanFactory.h"
#include "BlackHumanFactory.h"
#include <iostream>
using std::cout;
using std::endl;
using std::string;
void DoFactoryMethod1()
{
    cout << "----------第一批人是這樣的：黃種人工廠來生產黃種人" << endl;
    IHumanFactory *pHumanFactory = new CYellowHumanFactory();
    IHuman *pHuman = pHumanFactory->CreateHuman();
    pHuman->Cry();
    pHuman->Laugh();
    pHuman->Talk();
    delete pHuman;
    delete pHumanFactory;
}
void DoFactoryMethod2()
{
    cout << "----------第二批人是這樣的：白種人工廠來生產白種人" << endl;
    IHumanFactory *pHumanFactory = new CWhiteHumanFactory();
    IHuman *pHuman = pHumanFactory->CreateHuman();
    pHuman->Cry();
    pHuman->Laugh();
    pHuman->Talk();
    delete pHuman;
    delete pHumanFactory;
}
void DoFactoryMethod3()
{
    cout << "----------第一批人是這樣的：黑種人工廠來生產黑種人" << endl;
    IHumanFactory *pHumanFactory = new CBlackHumanFactory();
    IHuman *pHuman = pHumanFactory->CreateHuman();
    pHuman->Cry();
    pHuman->Laugh();
    pHuman->Talk();
    delete pHuman;
    delete pHumanFactory;
}
int _tmain(int argc, _TCHAR* argv[])
{
    //Factory 方法
    cout << "----------Factory 方法：" << endl;
    DoFactoryMethod1();
    DoFactoryMethod2();
    DoFactoryMethod3();
   
    _CrtSetDbgFlag(_CRTDBG_LEAK_CHECK_DF | _CRTDBG_ALLOC_MEM_DF);
    _CrtDumpMemoryLeaks();
    return 0;
}

Factory 方法屬於建立型模式，適合於產品不太多的情況。產品如果很多，則需要用抽象工廠來實現。