Factory Pattern

1.Factory模式两个最重要的功能

（1）定义创建对象的接口，封装了对象的创建。

（2）使得具体化类的工作延迟到了子类中。

2.Factory模式结构示意图

3.实现

 #ifndef _PRODUCT_H_
 #define _PRODUCT_H_

 class Product
 {
 public:
     virtual ~Product() = ;
 protected:
     Product();
 private:
 };

 class ConcreteProduct:public Product
 {
 public:
     ~ConcreteProduct();
     ConcreteProduct();
 protected:
 private:
 };

 #endif

Product.h

 #include "Product.h"
 #include <iostream>
 using namespace std;

 Product::Product()
 {

 }
 Product::~Product()
 {

 }

 ConcreteProduct::ConcreteProduct()
 {
     cout<<"ConcreteProduct..."<<endl;
 }
 ConcreteProduct::~ConcreteProduct()
 {

 }

Product.cpp

 #ifndef _FACTORY_H_
 #define _FACTORY_H_

 class Product;

 class Factory
 {
 public:
     virtual ~Factory() = ;
     virtual Product* CreateProduct() = ;
 protected:
     Factory();
 private:
 };

 class ConcreteFactory:public Factory
 {
 public:
     ~ConcreteFactory();
     ConcreteFactory();
     Product* CreateProduct();
 protected:
 private:
 };
 #endif

Factory.h

 #include "Factory.h"
 #include "Product.h"

 #include <iostream>
 using namespace std;

 Factory::Factory()
 {

 }
 Factory::~Factory()
 {

 }
 ConcreteFactory::ConcreteFactory()
 {
     cout<<"ConcreteFactory....."<<endl;
 }
 ConcreteFactory::~ConcreteFactory()
 {

 }
 Product* ConcreteFactory::CreateProduct()
 {
     return new ConcreteProduct();
 }

Factory.cpp