单身人士抽象工厂模式

Question

我想实现一个抽象工厂模式,但也想成为一个单例.

class WindowFactory {
protected:
    virtual Scrollbar* createScrollbar() = 0;
};

class MacWindowFactory: public WindowFactory {
    virtual Scrollbar* createScrollbar() {
        //return a instance
    }
    ;
};

class LinuxWindowFactory: public WindowFactory {
    virtual ScrollBar* createScrollbar() {
        //return a instance
    }
    ;
};

有人可以帮我提供一些制作这个抽象工厂单例的示例代码吗？

提前致谢.

Answer 1

我设法提出了更优雅的解决方案(截至目前没有错误检查).请告诉我你的想法

#include<iostream>
#include<map>

class AbstractFactory
{
private:
    typedef std::map< std::string, AbstractFactory* > ClientMap;
    static ClientMap s_clientMap;
public:
    void virtual createScrollbar() = 0;
    void virtual createWindow() = 0;
    static AbstractFactory* createInstance( std::string client );
protected:
    void Register( std::string, AbstractFactory* );
};

AbstractFactory::ClientMap AbstractFactory::s_clientMap;

class LinuxFactory: public AbstractFactory
{
public:
    void createScrollbar()
    {
        std::cout<<"Scrollbar for Linux"<<std::endl;
    }

    void createWindow()
    {
        std::cout<<"WIndow for Linux"<<std::endl;
    }
private:
    LinuxFactory()
    {
        Register( "Linux", this );
    }
    LinuxFactory( const LinuxFactory& );
    static LinuxFactory s_LinuxFactory;

};
LinuxFactory LinuxFactory::s_LinuxFactory;

class MacFactory: public AbstractFactory
{
public:
    void createScrollbar()
    {
        std::cout<<"Scrollbar for Mac"<<std::endl;
    }

    void createWindow()
    {
        std::cout<<"WIndow for Mac"<<std::endl;
    }

private:
    MacFactory()
    {
        Register( "Mac", this );
    }
    MacFactory( const MacFactory& );
    static MacFactory s_MacFactory;
};
MacFactory MacFactory::s_MacFactory;

void AbstractFactory::Register( std::string clientName, AbstractFactory* factory )
{
    s_clientMap.insert( ClientMap::value_type( clientName, factory ) );

}
AbstractFactory* AbstractFactory::createInstance( std::string client )
{
return s_clientMap.find( client )->second;

}

int main()
{
AbstractFactory *factory = AbstractFactory::createInstance( "Linux" );
factory->createScrollbar();
factory->createWindow();
}