code: protected final void fireValueChange(boolean oldValue, boolean newValue) {
          fireValueChange(Boolean.valueOf(oldValue), Boolean.valueOf(newValue));
      }
docs: Notifies all listeners that have registered interest for
  notification on this event type.  The event instance
  is lazily created using the parameters passed into
  the fire method.
  
  @param oldValue the boolean value before the change
  @param newValue the boolean value after the change