Adapter

Allows objects with incompatible interfaces to work together by wrapping one of the objects with an adapter that performs the necessary conversions.

Structure

• Target Interface: This is the interface that the client expects and uses.
• Adaptee: This is the class with an incompatible interface that needs to be adapted.
• Adapter: This class implements the target interface and wraps the adaptee. It translates the requests from the client into the method calls that are understood by the adaptee.
• Client: The client interacts with the system using the target interface, unaware that an adapter is being used behind the scenes.

Example

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

// Adaptee
class VLCPlayer {
    public void playVLC(String fileName) {
        System.out.println("Playing VLC file: " + fileName);
    }
}

// Adapter
class MediaAdapter implements MediaPlayer {
    private VLCPlayer vlcPlayer;

    public MediaAdapter() {
        vlcPlayer = new VLCPlayer();
    }

    @Override
    public void play(String audioType, String fileName) {
        if (audioType.equalsIgnoreCase("vlc")) {
            vlcPlayer.playVLC(fileName);
        }
    }
}

// Client
class AudioPlayer implements MediaPlayer {
    private MediaAdapter mediaAdapter;

    @Override
    public void play(String audioType, String fileName) {
        if (audioType.equalsIgnoreCase("vlc")) {
            mediaAdapter = new MediaAdapter();
            mediaAdapter.play(audioType, fileName);
        } else {
            System.out.println("Unsupported media type.");
        }
    }
}