package ch10.section02;

public class SubSingletonB
    extends SingletonB {
  public static boolean instanceFlag = false;
  public SubSingletonB() throws SingletonException {
    if (instanceFlag) {
      throw new SingletonException("Only can create a instance !");
    }
    else {
      instanceFlag = true;
      super.Register("Sub1", this);
    }
  }

  public void finalize() {
    instanceFlag = false;
  }
}