作用:
用原型實(shí)例指定創(chuàng)建對(duì)象的種類，并且通過(guò)拷貝這些原型創(chuàng)建新的對(duì)象。
UML結(jié)構(gòu)圖:
抽象基類:
1)Prototype:虛擬基類,所有原型的基類,提供Clone接口函數(shù)
接口函數(shù):
1)Prototype::Clone函數(shù):純虛函數(shù),根據(jù)不同的派生類來(lái)實(shí)例化創(chuàng)建對(duì)象.
解析:
Prototype模式其實(shí)就是常說(shuō)的"虛擬構(gòu)造函數(shù)"一個(gè)實(shí)現(xiàn),C++的實(shí)現(xiàn)機(jī)制中并沒(méi)有支持這個(gè)特性,但是通過(guò)不同派生類實(shí)現(xiàn)的Clone接口函數(shù)可以完成與"虛擬構(gòu)造函數(shù)"同樣的效果.舉一個(gè)例子來(lái)解釋這個(gè)模式的作用,假設(shè)有一家店鋪是配鑰匙的,他對(duì)外提供配制鑰匙的服務(wù)(提供Clone接口函數(shù)),你需要配什么鑰匙它不知道只是提供這種服務(wù),具體需要配什么鑰匙只有到了真正看到鑰匙的原型才能配好.也就是說(shuō),需要一個(gè)提供這個(gè)服務(wù)的對(duì)象,同時(shí)還需要一個(gè)原型(Prototype),不然不知道該配什么樣的鑰匙.
實(shí)現(xiàn):
1)Prototype.h
/**//********************************************************************
????created:????2006/07/20
????filename:?????Prototype.h
????author:????????李創(chuàng)
????????????????http://m.shnenglu.com/converse/
????purpose:????Prototype模式的演示代碼
*********************************************************************/
#ifndef?PROTOTYPE_H
#define?PROTOTYPE_H
//?虛擬基類,所有原型的基類,提供Clone接口函數(shù)
class?Prototype
{
public:
????Prototype(){}
????virtual?~Prototype(){}
????virtual?Prototype*?Clone()?=?0;
};
//?派生自Prototype,實(shí)現(xiàn)Clone方法
class?ConcreatePrototype1
????:?public?Prototype
{
public:
????ConcreatePrototype1();
????ConcreatePrototype1(const?ConcreatePrototype1&);
????virtual?~ConcreatePrototype1();
????virtual?Prototype*?Clone();
};
//?派生自Prototype,實(shí)現(xiàn)Clone方法
class?ConcreatePrototype2
????:?public?Prototype
{
public:
????ConcreatePrototype2();
????ConcreatePrototype2(const?ConcreatePrototype2&);
????virtual?~ConcreatePrototype2();
????virtual?Prototype*?Clone();
};
#endif2)Prototype.cpp
/**//********************************************************************
????created:????2006/07/20
????filename:?????Prototype.cpp
????author:????????李創(chuàng)
????????????????http://m.shnenglu.com/converse/
????purpose:????Prototype模式的演示代碼
*********************************************************************/
#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);
} 3)Main.cpp
/**//********************************************************************
????created:????2006/07/20
????filename:?????Main.cpp
????author:????????李創(chuàng)
????????????????http://m.shnenglu.com/converse/
????purpose:????Prototype模式的測(cè)試代碼
*********************************************************************/
#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;
}