{
    MappingHelper oldHelper = helper;
    helper = newHelper;
    if (eNotificationRequired())
    {
      ENotificationImpl notification = new ENotificationImpl(this, Notification.SET, MappingPackage.MAPPING__HELPER, oldHelper, newHelper);
      if (msgs == null) msgs = notification; else msgs.add(notification);
    }
    return msgs;
  }