Symfony translation loaded from databases

TranslationListener.php

<?php

namespace MainBundle\EventListener;

use Doctrine\ORM\EntityManager;
use Symfony\Bundle\FrameworkBundle\Translation\Translator;
use Symfony\Component\Cache\Adapter\AdapterInterface;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;

class TranslationListener
{
    /** @var Translator  */
    protected $translator;

    /** @var EntityManager */
    protected $entityManager;

    /** @var AdapterInterface */
    protected $cache;

    /**
     * RequestListener constructor.
     * @param Translator $translator
     * @param EntityManager $entityManager
     * @param AdapterInterface $cache
     */
    public function __construct(Translator $translator, EntityManager $entityManager, AdapterInterface $cache)
    {
        $this->translator = $translator;
        $this->entityManager = $entityManager;
        $this->cache = $cache;
    }

    public function onKernelRequest(GetResponseEvent $event)
    {
        if (!$event->isMasterRequest()) {
            return;
        }

        $catalogue = $this->translator->getCatalogue();

        $translationCache = $this->cache->getItem('translations.'.$this->translator->getLocale());
        if (!$translationCache->isHit())
        {
            // ... item does not exists in the cache

            $queryBuilder = $this->entityManager->createQueryBuilder();
            $queryBuilder
                ->select(array('t.code', 't.domain', 'tt.text'))
                ->from('MainBundle:Translation', 't')
                ->join('t.translations', 'tt')
                ->where('tt.locale = :locale')
                ->setParameter('locale', $this->translator->getLocale())
            ;

            $translations = $queryBuilder->getQuery()->getResult();

            $dbMessages = array();

            foreach($translations as $translation)
            {
                $dbMessages[$translation['domain']][$translation['code']] = $translation['text'];
            }

            $translationCache->set($dbMessages);
            $translationCache->expiresAfter(3600);
            $this->cache->save($translationCache);
        }
        else
        {
            $dbMessages = $translationCache->get();
        }

        foreach(array_keys($dbMessages) as $domain)
        {
            $catalogue->add($dbMessages[$domain], $domain);
        }

    }
}