设计模式第七篇-适配器模式

//原先的播放器接口
public interface MediaPlayer {
    void play(String audioType, String fileName);
}

//新的高级播放器接口
public interface AdvancedMediaPlayer {
    void playVlc(String fileName);
    void playMp4(String fileName);
}

//继承高级播放接口的MP4播放器
public class Mp4Player implements AdvancedMediaPlayer {
    @Override
    public void playVlc(String fileName) {
    }

    @Override
    public void playMp4(String fileName) {
        System.out.println("Playing mp4 file. Name: "+ fileName);
    }
}

//继承高级播放接口的VlC播放器
public class VlcPlayer implements AdvancedMediaPlayer {
    @Override
    public void playVlc(String fileName) {
        System.out.println("Playing vlc file. Name: "+ fileName);
    }

    @Override
    public void playMp4(String fileName) {

    }
}

//适配器类
public class MediaAdapter implements MediaPlayer {
    MediaAdapter mediaAdapter; 
    AdvancedMediaPlayer advancedMediaPlayer;

    public MediaAdapter(String audioType){
        if(audioType.equalsIgnoreCase("vlc")){
            advancedMediaPlayer=new VlcPlayer();
        }else{
            advancedMediaPlayer=new Mp4Player();
        }
    }

    @Override
    //将现在的接口方法转换成原先接口的方法
    public void play(String audioType, String fileName) {
        if(audioType.equalsIgnoreCase("vlc")){
            advancedMediaPlayer.playVlc(fileName);
        }else{
            advancedMediaPlayer.playMp4(fileName);
        }
    }
}
//播放器
public class AudioPlayer implements MediaPlayer  {
    MediaAdapter mediaAdapter;
    @Override
    public void play(String audioType, String fileName) {
        //播放 mp3 音乐文件的内置支持
        if(audioType.equalsIgnoreCase("mp3")){
            System.out.println("Playing mp3 file. Name: "+ fileName);
        }
        //mediaAdapter 提供了播放其他文件格式的支持
        else if(audioType.equalsIgnoreCase("vlc")
                || audioType.equalsIgnoreCase("mp4")){
            mediaAdapter = new MediaAdapter(audioType);
            mediaAdapter.play(audioType, fileName);
        }
        else{
            System.out.println("Invalid media. "+
                    audioType + " format not supported");
        }
    }
}
//实现
private static void adapter() {
        AudioPlayer audioPlayer = new AudioPlayer();
        audioPlayer.play("mp3", "beyond the horizon.mp3");
        audioPlayer.play("mp4", "alone.mp4");
        audioPlayer.play("vlc", "far far away.vlc");
        audioPlayer.play("avi", "mind me.avi");
    }