Newscoop\Services\UserTopicService::saveUserTopics PHP Метод

    public function saveUserTopics(SaveUserTopicsCommand $command)
    {
        if (empty($command->topics)) {
            $query = $this->em->createQuery('DELETE Newscoop\\Entity\\UserTopic ut WHERE ut.user = :user');
            $query->execute(array('user' => $command->userId));
        } else {
            $topics = $this->em->getRepository('Newscoop\\Entity\\UserTopic')->findByUser($command->userId);
            foreach ($topics as $topic) {
                if (in_array($topic->getTopicId(), $command->topics)) {
                    $this->em->remove($topic);
                }
            }
            $this->em->flush();
        }
        $user = $this->em->getReference('Newscoop\\Entity\\User', $command->userId);
        foreach ($command->selected as $topicId) {
            $language = $this->em->getReference('Newscoop\\Entity\\Language', $command->languageId);
            $topic = $this->em->getRepository('Newscoop\\NewscoopBundle\\Entity\\Topic')->getSingleTopicQuery($topicId, $language->getCode());
            $this->em->persist(new UserTopic($user, $topic->getOneOrNullResult()));
        }
        $this->em->flush();
    }