light.java

该程序是用jbuilder制作

package myoven.light;

public class Light {
  private static Light instance;
  private boolean isOn;
  public static Light getInstance(){
    if(instance==null){
      System.out.println("new a light");
      instance = new Light();
    }
    return instance;//返回唯一实例
  }

  public boolean getIsOn(){//返回灯状态
    return isOn;
  }
  public Light() {
    isOn=false;//初始等为关闭状态
  }
  public void turnOn(){
    isOn=true;
  }
  public void turnOff(){
    isOn=false;
  }
}