Doctrine\ODM\MongoDB\PersistentCollection::getReferences PHP Method

    public function getReferences()
    {
        return $this->references;
    }

    public function loadCollection(PersistentCollection $collection)
    {
        $mapping = $collection->getMapping();
        $cmd = $this->dm->getConfiguration()->getMongoCmd();
        $groupedIds = array();
        foreach ($collection->getReferences() as $reference) {
            $className = $this->dm->getClassNameFromDiscriminatorValue($mapping, $reference);
            $id = $reference[$cmd . 'id'];
            $reference = $this->dm->getReference($className, (string) $id);
            $collection->add($reference);
            if ($reference instanceof Proxy && ! $reference->__isInitialized__) {
                if ( ! isset($groupedIds[$className])) {
                    $groupedIds[$className] = array();
                }
                $groupedIds[$className][] = $id;
            }
        }

        foreach ($groupedIds as $className => $ids) {
            $mongoCollection = $this->dm->getDocumentCollection($className);
            $data = $mongoCollection->find(array('_id' => array($cmd . 'in' => $ids)));
            $hints = array(Builder::HINT_REFRESH => true);
            foreach ($data as $id => $documentData) {
                $document = $this->uow->getOrCreateDocument($className, $documentData, $hints);
            }
        }
    }