code: private void preSave(User user, boolean isNew) throws Exception
     {
        for (UserEventListener listener : listeners)
        {
           listener.preSave(user, isNew);
        }
     }
docs: Notifying listeners before user creation.
  
  @param user
  the user which is used in create operation
  @param isNew
  true, if we have a deal with new user, otherwise it is false
  which mean update operation is in progress
  @throws Exception
  if any listener failed to handle the event