适配器模式

适配器模式

适配器模式（Adapter Pattern）是作为两个不兼容的接口之间的桥梁。将一个类的接口转换成客户希望的另外一个接口。

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1、创建媒体播放器和高级媒体播放器接口

public interface MediaPlayer {
    void play(String audioType,String fileName);
}

public interface AdvanceMediaplayer {
    void playVLC(String fileName);
    void playMP4(String fileName);
}

2、高级播放器的2个实现类

public class MP4Player implements  AdvanceMediaplayer {
    @Override
    public void playVLC(String fileName) {

    }

    @Override
    public void playMP4(String fileName) {
        System.out.println("Playing mp4 file. Name:"+fileName);
    }
}

public class VLCPlayer implements  AdvanceMediaplayer{
    @Override
    public void playVLC(String fileName) {
        System.out.println("Playing vlc file. Name:" + fileName);
    }

    @Override
    public void playMP4(String fileName) {

    }
}

3、创建适配器

public class MediaAdapter implements MediaPlayer {
    AdvanceMediaplayer advanceMediaplayer;

    public MediaAdapter(String audioType){
        if (audioType.equalsIgnoreCase("vlc")){
            advanceMediaplayer = new VLCPlayer();
        }else if(audioType.equalsIgnoreCase("mp4")){
            advanceMediaplayer = new MP4Player();
        }
    }
    @Override
    public void play(String audioType, String fileName) {
        if(audioType.equalsIgnoreCase("vlc")){
            advanceMediaplayer.playVLC(fileName);
        }else if(audioType.equalsIgnoreCase("mp4")){
            advanceMediaplayer.playMP4(fileName);
        }
    }
}

4、媒体播放器的实现类

public class AudioPlayer implements MediaPlayer {
    private MediaAdapter mediaAdapter;
    @Override
    public void play(String audioType, String fileName) {
        if(audioType.equalsIgnoreCase("mp3")){
            System.out.println("Playing mp3 file. Name: "+ fileName);
        }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");
        }
    }
}

5、测试类

public class AdapterPatternDemo {
    public static void main(String[] args) {
        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");
    }
}

6、结果

Playing mp3 file. Name: beyond the horizon.mp3
Playing mp4 file. Name:alone.mp4
Playing vlc file. Name:far far away.vlc
Invalid media.aviformat not supported