设计模式--适配器模式（对象适配器）

对象适配器

对象适配器是对象的合成关系，也可以说是类的关联关系；
对象适配器，相比于类适配器，对象适配器是通过类间的关联关系进行耦合的，因此在设计时就可以做到比较灵活，实际项目中，使用的较多；

// 目标 
class IMediaPlayer{
public:
	virtual void play(string fileName) = 0;	
};

// 源 
class IAdvacneMediaPlayer{
public:
	virtual void playVlc(string fileName) = 0;
	virtual void playMp4(string fileName) = 0;	
};

class VlcPlayer : public IAdvacneMediaPlayer{
public:
	virtual void playVlc(string fileName){
		cout << "playing vlc file: " << fileName << endl;
	}
	
	virtual void playMp4(string fileName){
		
	}
};

class Mp4Player : public IAdvacneMediaPlayer{
public:
	virtual void playVlc(string fileName){
		
	}
	
	virtual void playMp4(string fileName){
		cout << "playing mp4 file: " << fileName << endl;
	}	
};

// VLC 适配器 
class VlcAudioMediaAdapter : public IMediaPlayer{
public:
	VlcAudioMediaAdapter(VlcPlayer* player){
		this->player = player;
	}
	
	virtual void play(string fileName){
		player->playVlc(fileName);
	}
	
private:
	VlcPlayer* player;			
};

// MP4 适配器 
class Mp4AudioMediaAdapter : public IMediaPlayer{
public:
	Mp4AudioMediaAdapter(Mp4Player* player){
		this->player = player;
	}
	
	virtual void play(string fileName){
		player->playMp4(fileName);
	}	
	
private:
	Mp4Player* player;		
};

int main(){
	IMediaPlayer* media = new VlcAudioMediaAdapter(new VlcPlayer);	
	media->play("/home/a.vlc");
	
	media = new Mp4AudioMediaAdapter(new Mp4Player);
	media->play("/home/b.mp4");
	
	return 0;
}