/** * Serialize extref to JSON * * @param JsonSerializationVisitor $visitor Visitor * @param ExtReference $extReference Extref * @param array $type Type * @param Context $context Context * @return string|null */ public function serializeExtReferenceToJson(JsonSerializationVisitor $visitor, ExtReference $extReference, array $type, Context $context) { try { return $visitor->visitString($this->converter->getUrl($extReference), $type, $context); } catch (\InvalidArgumentException $e) { return $visitor->visitNull(null, $type, $context); } }