protected function initialize()
    {
        if (is_array($this->objectIdentifiers)) {
            foreach ($this->objectIdentifiers as $identifier) {
                try {
                    parent::attach($this->persistenceManager->getObjectByIdentifier($identifier));
                } catch (Exception\InvalidObjectDataException $exception) {
                    // when security query rewriting holds back an object here, we skip it...
                }
            }
            $this->objectIdentifiers = null;
        }
    }