퍼사드 패턴 (Facade pattern)

퍼사드 패턴 (Facade pattern)

인터페이스를 단순화시킬 뿐 아니라 클라이언트와 구성요소들로 이루어진 서브시스템을 분리시켜주는 패턴 ^{출처: Head First Design Patterns}

쉽게 말해, 여러가지 기능들을 한 메소드로 잘 포장해두는 것이다.

다이어그램

^{출처: 위키피디아}

예제

홈 시어터^C#

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 object WatchMovie(string movie)
	{
		StringBuilder watchMovieString = new StringBuilder();

		watchMovieString.Append("Get ready to watch a movie...\n");
		watchMovieString.Append(popper.On());
		watchMovieString.Append(popper.Pop());
		watchMovieString.Append(lights.Dim(10));
		watchMovieString.Append(screen.Down());
		watchMovieString.Append(projector.On());
		watchMovieString.Append(projector.WideScreenMode());
		watchMovieString.Append(amp.On());
		watchMovieString.Append(amp.SetDvd(dvd));
		watchMovieString.Append(amp.SetSurroundSound());
		watchMovieString.Append(amp.SetVolume(5));
		watchMovieString.Append(dvd.On());
		watchMovieString.Append(dvd.Play(movie));

		return watchMovieString.ToString();
	}


	public object EndMovie()
	{
		StringBuilder endMovieString = new StringBuilder();

		endMovieString.Append("Shutting movie theater down...\n");
		endMovieString.Append(popper.Off());
		endMovieString.Append(lights.On());
		endMovieString.Append(screen.Up());
		endMovieString.Append(projector.Off());
		endMovieString.Append(amp.Off());
		endMovieString.Append(dvd.Stop());
		endMovieString.Append(dvd.Eject());
		endMovieString.Append(dvd.Off());

		return endMovieString.ToString();
	}

	public object ListenToCd(string cdTitle)
	{
		StringBuilder listenToCdString = new StringBuilder();

		listenToCdString.Append("Get ready for an audio experence...\n");
		listenToCdString.Append(lights.On());
		listenToCdString.Append(amp.On());
		listenToCdString.Append(amp.SetVolume(5));
		listenToCdString.Append(amp.SetCd(cd));
		listenToCdString.Append(amp.SetStereoSound());
		listenToCdString.Append(cd.On());
		listenToCdString.Append(cd.Play(cdTitle));

		return listenToCdString.ToString();
	}

	public object EndCd()
	{
		StringBuilder endCdString = new StringBuilder();

		endCdString.Append("Shutting down CD...\n");
		endCdString.Append(amp.Off());
		endCdString.Append(amp.SetCd(cd));
		endCdString.Append(cd.Eject());
		endCdString.Append(cd.Off());

		return endCdString.ToString();
	}

	public object ListenToRadio(double frequency)
	{
		StringBuilder listenToRadioString = new StringBuilder();

		listenToRadioString.Append("Tuning in the airwaves...\n");
		listenToRadioString.Append(tuner.On());
		listenToRadioString.Append(tuner.SetFrequency(frequency));
		listenToRadioString.Append(amp.On());
		listenToRadioString.Append(amp.SetVolume(5));
		listenToRadioString.Append(amp.SetTuner(tuner));

		return listenToRadioString.ToString();
	}

	public object EndRadio()
	{
		StringBuilder endRadioString = new StringBuilder();

		endRadioString.Append("Shutting down the tuner...\n");
		endRadioString.Append(tuner.Off());
		endRadioString.Append(amp.Off());

		return endRadioString.ToString();
	}
}