Sulu\Bundle\MediaBundle\Entity\CollectionRepository::findCollectionByKey PHP Method

    public function findCollectionByKey($key)
    {
        $queryBuilder = $this->createQueryBuilder('collection')->leftJoin('collection.meta', 'collectionMeta')->leftJoin('collection.defaultMeta', 'defaultMeta')->where('collection.key = :key');
        $query = $queryBuilder->getQuery();
        $query->setParameter('key', $key);
        try {
            return $query->getSingleResult();
        } catch (NoResultException $ex) {
            return;
        }
    }