public function getPartFactoryService()
    {
        if ($this->partFactoryService === null) {
            $this->partFactoryService = new PartFactoryService(
                $this->getPartFilterFactory(),
                $this->getStreamFactory(),
                $this->getPartStreamFilterManagerFactory(),
                $this->getMessageHelperService()
            );
        }
        return $this->partFactoryService;
    }