HeadFirst设计模式之门面模式

一、

1.The Facade Pattern provides a unifi ed interface to a set of interfaces in a subsytem. Facade defi nes a higher-level interface that makes the subsystem easier to use.

2.Facades and adapters may wrap multiple classes, but a facade’s intent is to simplify, while an adapter’s is to convert

the interface to something different.

3.

4.

二、

实现家庭影院

1.

package headfirst.designpatterns.facade.hometheater;

public class HomeTheaterFacade {
    Amplifier amp;
    Tuner tuner;
    DvdPlayer dvd;
    CdPlayer cd;
    Projector projector;
    TheaterLights lights;
    Screen screen;
    PopcornPopper popper;
 
    public HomeTheaterFacade(Amplifier amp, 
                 Tuner tuner, 
                 DvdPlayer dvd, 
                 CdPlayer cd, 
                 Projector projector, 
                 Screen screen,
                 TheaterLights lights,
                 PopcornPopper popper) {
 
        this.amp = amp;
        this.tuner = tuner;
        this.dvd = dvd;
        this.cd = cd;
        this.projector = projector;
        this.screen = screen;
        this.lights = lights;
        this.popper = popper;
    }
 
    public void watchMovie(String movie) {
        System.out.println("Get ready to watch a movie...");
        popper.on();
        popper.pop();
        lights.dim(10);
        screen.down();
        projector.on();
        projector.wideScreenMode();
        amp.on();
        amp.setDvd(dvd);
        amp.setSurroundSound();
        amp.setVolume(5);
        dvd.on();
        dvd.play(movie);
    }
 
 
    public void endMovie() {
        System.out.println("Shutting movie theater down...");
        popper.off();
        lights.on();
        screen.up();
        projector.off();
        amp.off();
        dvd.stop();
        dvd.eject();
        dvd.off();
    }

    public void listenToCd(String cdTitle) {
        System.out.println("Get ready for an audiopile experence...");
        lights.on();
        amp.on();
        amp.setVolume(5);
        amp.setCd(cd);
        amp.setStereoSound();
        cd.on();
        cd.play(cdTitle);
    }

    public void endCd() {
        System.out.println("Shutting down CD...");
        amp.off();
        amp.setCd(cd);
        cd.eject();
        cd.off();
    }

    public void listenToRadio(double frequency) {
        System.out.println("Tuning in the airwaves...");
        tuner.on();
        tuner.setFrequency(frequency);
        amp.on();
        amp.setVolume(5);
        amp.setTuner(tuner);
    }

    public void endRadio() {
        System.out.println("Shutting down the tuner...");
        tuner.off();
        amp.off();
    }
}

2.

package headfirst.designpatterns.facade.hometheater;

public class HomeTheaterTestDrive {
    public static void main(String[] args) {
        Amplifier amp = new Amplifier("Top-O-Line Amplifier");
        Tuner tuner = new Tuner("Top-O-Line AM/FM Tuner", amp);
        DvdPlayer dvd = new DvdPlayer("Top-O-Line DVD Player", amp);
        CdPlayer cd = new CdPlayer("Top-O-Line CD Player", amp);
        Projector projector = new Projector("Top-O-Line Projector", dvd);
        TheaterLights lights = new TheaterLights("Theater Ceiling Lights");
        Screen screen = new Screen("Theater Screen");
        PopcornPopper popper = new PopcornPopper("Popcorn Popper");
 
        HomeTheaterFacade homeTheater = 
                new HomeTheaterFacade(amp, tuner, dvd, cd, 
                        projector, screen, lights, popper);
 
        homeTheater.watchMovie("Raiders of the Lost Ark");
        homeTheater.endMovie();
    }
}

3.

package headfirst.designpatterns.facade.hometheater;

public class Amplifier {
    String description;
    Tuner tuner;
    DvdPlayer dvd;
    CdPlayer cd;
    
    public Amplifier(String description) {
        this.description = description;
    }
 
    public void on() {
        System.out.println(description + " on");
    }
 
    public void off() {
        System.out.println(description + " off");
    }
 
    public void setStereoSound() {
        System.out.println(description + " stereo mode on");
    }
 
    public void setSurroundSound() {
        System.out.println(description + " surround sound on (5 speakers, 1 subwoofer)");
    }
 
    public void setVolume(int level) {
        System.out.println(description + " setting volume to " + level);
    }

    public void setTuner(Tuner tuner) {
        System.out.println(description + " setting tuner to " + dvd);
        this.tuner = tuner;
    }
  
    public void setDvd(DvdPlayer dvd) {
        System.out.println(description + " setting DVD player to " + dvd);
        this.dvd = dvd;
    }
 
    public void setCd(CdPlayer cd) {
        System.out.println(description + " setting CD player to " + cd);
        this.cd = cd;
    }
 
    public String toString() {
        return description;
    }
}

4.

package headfirst.designpatterns.facade.hometheater;

public class Tuner {
    String description;
    Amplifier amplifier;
    double frequency;

    public Tuner(String description, Amplifier amplifier) {
        this.description = description;
    }

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

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

    public void setFrequency(double frequency) {
        System.out.println(description + " setting frequency to " + frequency);
        this.frequency = frequency;
    }

    public void setAm() {
        System.out.println(description + " setting AM mode");
    }

    public void setFm() {
        System.out.println(description + " setting FM mode");
    }

    public String toString() {
        return description;
    }
}