FriendsOfSymfony / FOSElasticaBundle

    {

        $document = new Document($identifier, [], '', $this->options['index']);

        if ($this->dispatcher) {

            $event = new TransformEvent($document, $fields, $object);

            $this->dispatcher->dispatch(TransformEvent::PRE_TRANSFORM, $event);

            $document = $event->getDocument();

        }

        foreach ($fields as $key => $mapping) {

            if ('_parent' == $key) {

            $document->set($key, $this->normalizeValue($value));

        }

        if ($this->dispatcher) {

            $event = new TransformEvent($document, $fields, $object);

            $this->dispatcher->dispatch(TransformEvent::POST_TRANSFORM, $event);

            $document = $event->getDocument();

        }

        return $document;

    }