code: public function validate($value, Constraint $constraint)
      {
          $nodesSameRoute = $this->nodeRepository->findByParentAndRoutePattern(
              $value->getParentId(),
              $value->getRoutePattern(),
              $value->getNodeId(),
              $value->getSiteId()
          );
          if (0 < count($nodesSameRoute)) {
              $nodesSameRoute = current($nodesSameRoute);
              $message = $constraint->message;
              if (true === $nodesSameRoute->isDeleted()) {
                  $message = $constraint->messageWitNodeDeleted;
              }
              $this->context->buildViolation($message, array("%nodeName%" => $nodesSameRoute->getName()))
                  ->atPath('routePattern')
                  ->addViolation();
          }
      }
docs: Checks if the passed value is valid.
  
  @param NodeInterface $value The value that should be validated
  @param Constraint    $constraint The constraint for the validation