设计模式之门面模式

// 子系统类
class DVDPlayer {
    public void on() { System.out.println("DVD Player on"); }
    public void play(String movie) { System.out.println("Playing " + movie); }
    public void off() { System.out.println("DVD Player off"); }
}

class Projector {
    public void on() { System.out.println("Projector on"); }
    public void setInput(String input) { System.out.println("Projector input set to " + input); }
    public void off() { System.out.println("Projector off"); }
}

class Lights {
    public void dim(int level) { System.out.println("Lights dimmed to " + level + "%"); }
    public void on() { System.out.println("Lights on"); }
}

// 门面类
class HomeTheaterFacade {
    private DVDPlayer dvd;
    private Projector projector;
    private Lights lights;

    public HomeTheaterFacade(DVDPlayer dvd, Projector projector, Lights lights) {
        this.dvd = dvd;
        this.projector = projector;
        this.lights = lights;
    }

    public void watchMovie(String movie) {
        System.out.println("Get ready to watch a movie...");
        lights.dim(10);
        projector.on();
        projector.setInput("DVD");
        dvd.on();
        dvd.play(movie);
    }

    public void endMovie() {
        System.out.println("Shutting movie theater down...");
        lights.on();
        projector.off();
        dvd.off();
    }
}

// 客户端代码
public class Client {
    public static void main(String[] args) {
        DVDPlayer dvd = new DVDPlayer();
        Projector projector = new Projector();
        Lights lights = new Lights();
        
        HomeTheaterFacade homeTheater = new HomeTheaterFacade(dvd, projector, lights);
        homeTheater.watchMovie("Inception");
        homeTheater.endMovie();
    }
}