23种设计模式之二（创建型模式）AbstactFactory模式

一、简介

        AbstractFactory 模式就是用来解决要创建一组相关或者相互依赖的对象的问题。如下图AbstractFactory 模式典型的结构图，其中ProductA和ProductB依赖于ConcreteFactory的对象，Product它们对象的创建被封装到用于创建对象的类ConcreteFactory中，这样只用维护一个创建对象ConcreteFactory类，比维护n多Product的相关对象的创建过程要简单的多，简化了维护的成本和工作。

二、详解

1、代码实现

（完整代码已上传到csdn）

（1）代码product.h：

#ifndef _PRODUCT_H_#define _PRODUCT_H_class AbstractProductA{    public:        virtual ~AbstractProductA();    protected:        AbstractProductA();    private:};class AbstractProductB{    public:        virtual ~AbstractProductB();    protected:        AbstractProductB();    private:};class ProductA1 : public AbstractProductA{    public:        ProductA1();        ~ProductA1();    protected:    private:};class ProductA2 : public AbstractProductA{    public:        ProductA2();        ~ProductA2();    protected:    private:};class ProductB1 : public AbstractProductB{    public:        ProductB1();        ~ProductB1();    protected:    private:};class ProductB2 : public AbstractProductB{    public:        ProductB2();        ~ProductB2();    protected:    private:};#endif

（2）代码product.cpp：

#include <iostream>#include "product.h"using namespace std;AbstractProductA::AbstractProductA(){}AbstractProductA::~AbstractProductA(){}AbstractProductB::AbstractProductB(){}AbstractProductB::~AbstractProductB(){}ProductA1::ProductA1(){    cout<<"---ProductA1 constructor"<<endl;}ProductA1::~ProductA1(){    cout<<"---ProductA1 destructor"<<endl;}ProductA2::ProductA2(){    cout<<"---ProductA2 constructor"<<endl;}ProductA2::~ProductA2(){    cout<<"---ProductA2 destructor"<<endl;}ProductB1::ProductB1(){    cout<<"+++ProductB1 constructor"<<endl;}ProductB1::~ProductB1(){    cout<<"+++ProductB1 destructor"<<endl;}ProductB2::ProductB2(){    cout<<"+++ProductB2 constructor"<<endl;}ProductB2::~ProductB2(){    cout<<"+++ProductB2 destructor"<<endl;}

（3）代码abstractfactory.h：

#ifndef _ABSTRACTFACTORY_H_#define _ABSTRACTFACTORY_H_class AbstractProductA;class AbstractProductB;class AbstractFactory{    public:        virtual ~AbstractFactory();        virtual AbstractProductA *CreateProductA() = 0;        virtual AbstractProductB *CreateProductB() = 0;    protected:        AbstractFactory();        AbstractProductA *pointA1;        AbstractProductA *pointA2;        AbstractProductB *pointB1;        AbstractProductB *pointB2;    private:};class ConcreteFactory1 : public AbstractFactory{    public:        ConcreteFactory1();        ~ConcreteFactory1();        AbstractProductA *CreateProductA();        AbstractProductB *CreateProductB();    protected:    private:};class ConcreteFactory2 : public AbstractFactory{    public:        ConcreteFactory2();        ~ConcreteFactory2();        AbstractProductA *CreateProductA();        AbstractProductB *CreateProductB();    protected:    private:};#endif

（4）代码abstractfactory.cpp：

#include <iostream>#include "product.h"#include "abstractfactory.h"using namespace std;AbstractFactory::AbstractFactory(){    cout<<"father:AbstractFactory constructor"<<endl;    pointA1 = NULL;    pointA2 = NULL;    pointB1 = NULL;    pointB2 = NULL;}AbstractFactory::~AbstractFactory(){    cout<<"father:AbstractFactory destructor"<<endl;    if (pointA1)  delete pointA1;    if (pointA2)  delete pointA2;    if (pointB1)  delete pointB1;    if (pointB2)  delete pointB2;}ConcreteFactory1::ConcreteFactory1(){}ConcreteFactory1::~ConcreteFactory1(){}AbstractProductA *ConcreteFactory1::CreateProductA(){    cout<<"ConcreteFactory1:new ProductA1()"<<endl;    pointA1 = new ProductA1();    return pointA1;}AbstractProductB *ConcreteFactory1::CreateProductB(){    cout<<"ConcreteFactory1:new ProductB1()"<<endl;    pointB1 = new ProductB1();    return pointB1;}ConcreteFactory2::ConcreteFactory2(){}ConcreteFactory2::~ConcreteFactory2(){}AbstractProductA *ConcreteFactory2::CreateProductA(){    cout<<"ConcreteFactory2:new ProductA2()"<<endl;    pointA2 = new ProductA2();    return pointA2;}AbstractProductB *ConcreteFactory2::CreateProductB(){    cout<<"ConcreteFactory2:new ProductB2()"<<endl;    pointB2 = new ProductB2();    return pointB2;}

（5）代码main.cpp：

#include <iostream>#include "abstractfactory.h"using namespace std;int main(){    AbstractFactory *cf1 = new ConcreteFactory1();    cf1->CreateProductA();    cf1->CreateProductB();        AbstractFactory *cf2 = new ConcreteFactory2();    cf2->CreateProductA();    cf2->CreateProductB();    delete cf1;    delete cf2;    return 0;}

（6）makefile：

CFLAGS = -gDEFINED = #-D _VERSIONLIBS = CC = g++INCLUDES = -I./OBJS= main.o abstractfactory.o product.oTARGET= mainall:$(TARGET)$(TARGET):$(OBJS)$(CC) $(CFLAGS) -o $@ $(OBJS).SUFFIXES:.o .h.SUFFIXES:.cpp .o.cpp.o:$(CC) $(DEFINED) -c $(CFLAGS) -o $@ $<ok:./$(TARGET)clean:rm -f $(OBJS) $(TARGET) core *.log

2、运行结果

（centos6.3系统中运行结果：）

三、总结

（1）AbstractFactory 模式和 Factory 模式的差异是使用设计模式时候的一个容易引起困惑的地方，实际上AbstractFactory 模式是为创建一组(有多类)相关或依赖的对象提供创建接口，而 Factory 模式是为一类对象提供创建接口或延迟对象的创建到子类中实现，并且可以看到AbstractFactory 模式通常都是使用 Factory 模式实现(ConcreteFactory1)。

（2）源码已经打包上传到csdn上可登录下载（http://download.csdn.net/detail/taiyang1987912/8403151）。