public function getTagCloud($max_tags)

    {

        $qb = $this->getEntityManager()->createQueryBuilder();

        $qb->select('t.id', 't.label', 'COUNT( dt.id ) AS nb_docs');

        $qb->from('WikiTagBundle:Tag','t');

        $qb->leftJoin('t.documents', 'dt', 'WITH', 't = dt.tag');

        $qb->addGroupBy('t.id');

        $qb->addOrderBy('nb_docs','DESC');

        $qb->setMaxResults($max_tags);

        $query = $qb->getQuery();

        return $query->getResult();

    }

    public function getCompletion($seed)

    {

        $qb = $this->getEntityManager()->createQueryBuilder();

        $qb->select('t.label');

        $qb->from('WikiTagBundle:Tag','t');

        $qb->where($qb->expr()->orx(

            $qb->expr()->like('t.label',$qb->expr()->literal("%".addcslashes(mysql_real_escape_string($seed),"%_"))),

            $qb->expr()->like('t.label',$qb->expr()->literal("% ".addcslashes(mysql_real_escape_string($seed),"%_")."%"))

        ));

        $query = $qb->getQuery();

        return $query->getResult();

    }