/**
  * Retrieves vendor title.
  *
  * @param Article         $entity
  * @param ProductDocument $document
  */
 protected function extractVendor(Article $entity, ProductDocument $document)
 {
     try {
         $document->setVendor($entity->getVendor()->getTitle());
     } catch (EntityNotFoundException $exception) {
         // No vendor. Just ignore.
     }
 }