外观模式（封装交互，简化调用）

public class Client {

    public static void main(String[] args) {
        // 创建交互的上下文对象 —— 即"谁与机器人在交互"。
        HumanComputerInteraction.Context context = new HumanComputerInteraction.Context(new Machine("Samu"), new User("Alice"));
        // 创建人机交互对象
        HumanComputerInteraction interaction = new HumanComputerInteraction(context);
        // 初始化人机交互
        interaction.setUp();
    }
}

public class HumanComputerInteraction {

    private Context context;

    public HumanComputerInteraction(HumanComputerInteraction.Context context) {
        this.context = context;
    }

    public void setUp() {
        // 初始化曲库
        final Machine machine = context.getMachine();
        final MusicDatabase database = machine.getDatabase();
        database.initDatabase();
        // 初始化命令
        final Invoker invoker = context.getInvoker();
        invoker.invoke(new CommandAdapter(CookCommandImpl.KEY_COOK, "红烧肉", context));
        invoker.invoke(new CommandAdapter(DanceCommandImpl.KEY_DANCE, "肚皮舞", context));
        invoker.invoke(new CommandAdapter(SongCommandImpl.KEY_SONG, "千里之外", context));
    }
}