protected function registerNew(PersistentObject $object) {
    $key = $object->getOID()->__toString();
    if (self::$isDebugEnabled) {
      self::$logger->debug("Register new object: ".$key);
    }
    $this->newObjects[$key] = $object;
    $this->observedObjects[$key] = $object;
    return $object;
  }