Facade模式

Facade 客户端可以调用这个角色的方法。此角色知晓相关的(一个或者多个)子系统的功能和责任。在正常情况下，本角色会将所有从客户端发来的请求委派到相应的子系统去。

subsystem 可以同时有一个或者多个子系统。每一个子系统都不是一个单独的类，而是一个类的集合。每一个子系统都可以被客户端直接调用，或者被门面角色调用。子系统并不知道门面的存在，对于子系统而言，门面仅仅是另外一个客户端而已。

public class Camera {  public void TurnOn() {    System.out.println("Turning on the camera.");  }

  public void TurnOff() {    System.out.println("Turning off the camera.");  }

  public void Rotate(int degrees) {    System.out.println("Rotating the camera by {0} degrees.", degrees);  }}

public class Light {  public void TurnOff() {    System.out.println("Turning on the light.");  }

  public void TurnOn() {    System.out.println("Turning off the light.");  }

  public void ChangeBulb() {    System.out.println("changing the light-bulb.");  }}

public class Sensor {  public void Activate() {    System.out.println("Activating the sensor.");  }

  public void Deactivate() {    System.out.println("Deactivating the sensor.");  }

  public void Trigger() {    System.out.println("The sensor has triggered.");  }}

public class Alarm {  public void Activate() {    System.out.println("Activating the alarm.");  }

  public void Deactivate() {    System.out.println("Deactivating the alarm.");  }

  public void Ring() {    System.out.println("Ringing the alarm.");  }

  public void StopRing() {    System.out.println("Stop the alarm.");  }}

public class SecurityFacade {  private static Camera camera1, camera2;  private static Light light1, light2, light3;  private static Sensor sensor;  private static Alarm alarm;

  static SecurityFacade() {    camera1 = new Camera();    camera2 = new Camera();    light1 = new Light();    light2 = new Light();    light3 = new Light();    sensor = new Sensor();    alarm = new Alarm();  }    public void Activate() {    camera1.TurnOn();    camera2.TurnOn();    light1.TurnOn();    light2.TurnOn();    light3.TurnOn();    sensor.Activate();    alarm.Activate();  }

  public void Deactivate() {    camera1.TurnOff();    camera2.TurnOff();    light1.TurnOff();    light2.TurnOff();    light3.TurnOff();    sensor.Deactivate();    alarm.Deactivate();  }}

public class Client {  private static SecurityFacade security;

  public static void Main( string[] args )  {    security = new SecurityFacade();    security.Activate();    System.out.println("/n--------------------/n");    security.Deactivate();  }}