Prototype设计模式

 

Prototype模式其实就是常说的"虚拟构造函数"一个实现,C++的实现机制中并没有支持这个特性,但是通过不同派生类实现的Clone接口函数可以完成与"虚拟构造函数"同样的效果. Prototype模式提供了一个通过已存在对象进行新对象创建的接口（Clone），Clone（）实现和具体的实现语言相关，在C++中我们将通过拷贝构造函数实现之。Prototype模式提供自我复制的功能，即新对象的创建可以通过已有对象进行创建。

 

#ifndef PROTOTYPE_H

#define PROTOTYPE_H

// 虚拟基类,所有原型的基类,提供Clone接口函数

class Prototype

{

public:

Prototype(){}

virtual ~Prototype(){}

virtual Prototype* Clone() = 0;

};

// 派生自Prototype,实现Clone方法

class ConcreatePrototype1 : public Prototype

{

public:

ConcreatePrototype1();

ConcreatePrototype1(const ConcreatePrototype1&);

virtual ~ConcreatePrototype1();

virtual Prototype* Clone();

};

// 派生自Prototype,实现Clone方法

class ConcreatePrototype2: public Prototype

{

public:

ConcreatePrototype2();

ConcreatePrototype2(const ConcreatePrototype2&);

virtual ~ConcreatePrototype2();

virtual Prototype* Clone();

};

#endif

 

 

#include "Prototype.h"

#include <iostream>

ConcreatePrototype1::ConcreatePrototype1()

{

std::cout << "construction of ConcreatePrototype1/n";

}

ConcreatePrototype1::~ConcreatePrototype1()

{

std::cout << "destruction of ConcreatePrototype1/n";

}

ConcreatePrototype1::ConcreatePrototype1(const ConcreatePrototype1&)

{

std::cout << "copy construction of ConcreatePrototype1/n";

}

Prototype* ConcreatePrototype1::Clone()

{

return new ConcreatePrototype1(*this);

}

 

ConcreatePrototype2::ConcreatePrototype2()

{

std::cout << "construction of ConcreatePrototype2/n";

}

ConcreatePrototype2::~ConcreatePrototype2()

{

std::cout << "destruction of ConcreatePrototype2/n";

}

ConcreatePrototype2::ConcreatePrototype2(const ConcreatePrototype2&)

{

std::cout << "copy construction of ConcreatePrototype2/n";

}

Prototype* ConcreatePrototype2::Clone()

{

return new ConcreatePrototype2(*this);

}

 

 

#include "Prototype.h"

#include <stdlib.h>

int main()

{

Prototype* pPrototype1 = new ConcreatePrototype1();

Prototype* pPrototype2 = pPrototype1->Clone();

Prototype* pPrototype3 = new ConcreatePrototype2();

Prototype* pPrototype4 = pPrototype3->Clone();

delete pPrototype1;

delete pPrototype2;

delete pPrototype3;

delete pPrototype4;

system("pause");

return 0;

}