外观模式

外观模式也称过程模式，外观模式通过调用统一的接口，可以屏蔽内部子系统的细节，使得调用端只需要和这个接口发生关系，而无需关系内部的实现细节。

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public class DVDPlayer {
    
    //使用单例模式, 使用饿汉式
    private static DVDPlayer instance = new DVDPlayer();
    
    public static DVDPlayer getInstanc() {
        return instance;
    }
    
    public void on() {
        System.out.println(" dvd on ");
    }
    public void off() {
        System.out.println(" dvd off ");
    }
    
    public void play() {
        System.out.println(" dvd is playing ");
    }
    
    public void pause() {
        System.out.println(" dvd pause ..");
    }
}
public class Popcorn {
    
    private static Popcorn instance = new Popcorn();
    
    public static Popcorn getInstance() {
        return instance;
    }
    
    public void on() {
        System.out.println(" popcorn on ");
    }
    
    public void off() {
        System.out.println(" popcorn ff ");
    }
    
    public void pop() {
        System.out.println(" popcorn is poping  ");
    }
}
public class Projector {

    private static Projector instance = new Projector();
    
    public static Projector getInstance() {
        return instance;
    }
    
    public void on() {
        System.out.println(" Projector on ");
    }
    
    public void off() {
        System.out.println(" Projector ff ");
    }
    
    public void focus() {
        System.out.println(" Projector is Projector  ");
    }
    
}
public class Screen {

    private static Screen instance = new Screen();
    
    public static Screen getInstance() {
        return instance;
    }
    
    public void up() {
        System.out.println(" Screen up ");
    }
    
    public void down() {
        System.out.println(" Screen down ");
    }
    
}
public class Stereo {

    private static Stereo instance = new Stereo();
    
    public static Stereo getInstance() {
        return instance;
    }
    
    public void on() {
        System.out.println(" Stereo on ");
    }
    
    public void off() {
        System.out.println(" Screen off ");
    }
    
    public void up() {
        System.out.println(" Screen up.. ");
    }
}
public class TheaterLight {

    private static TheaterLight instance = new TheaterLight();

    public static TheaterLight getInstance() {
        return instance;
    }

    public void on() {
        System.out.println(" TheaterLight on ");
    }

    public void off() {
        System.out.println(" TheaterLight off ");
    }

    public void dim() {
        System.out.println(" TheaterLight dim.. ");
    }

    public void bright() {
        System.out.println(" TheaterLight bright.. ");
    }
}

public class HomeTheaterFacade {
    
    //定义各个子系统对象
    private TheaterLight theaterLight;
    private Popcorn popcorn;
    private Stereo stereo;
    private Projector projector;
    private Screen screen;
    private DVDPlayer dVDPlayer;
    
    
    //构造器
    public HomeTheaterFacade() {
        super();
        this.theaterLight = TheaterLight.getInstance();
        this.popcorn = Popcorn.getInstance();
        this.stereo = Stereo.getInstance();
        this.projector = Projector.getInstance();
        this.screen = Screen.getInstance();
        this.dVDPlayer = DVDPlayer.getInstanc();
    }

    //操作分成 4 步
    
    public void ready() {
        popcorn.on();
        popcorn.pop();
        screen.down();
        projector.on();
        stereo.on();
        dVDPlayer.on();
        theaterLight.dim();
    }
    
    public void play() {
        dVDPlayer.play();
    }
    
    public void pause() {
        dVDPlayer.pause();
    }
    
    public void end() {
        popcorn.off();
        theaterLight.bright();
        screen.up();
        projector.off();
        stereo.off();
        dVDPlayer.off();
    }

}

public class Client {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        //这里直接调用。。 很麻烦
        HomeTheaterFacade homeTheaterFacade = new HomeTheaterFacade();
        homeTheaterFacade.ready();
        homeTheaterFacade.play();
        homeTheaterFacade.end();
    }
}