protected function join(QueryBuilder $queryBuilder, $join, $alias, $joinType)
{
list($entity) = explode('.', $join);
$joinParts = $queryBuilder->getDQLPart('join');
if (!array_key_exists($entity, $joinParts)) {
return $queryBuilder->join($join, $alias);
}
return $this->filterExistingJoins($queryBuilder, $joinParts[$entity], $alias, $join, $joinType);
}