code: public function jsonSerialize()
      {
          $json = [];
  
          if (null !== $this->systemName) {
              $json['systemName'] = $this->systemName;
          }
          if (null !== $this->value) {
              $json['value'] = $this->value;
          }
          if (null !== $this->operator) {
              $json['operator'] = $this->operator;
          }
  
          return $json;
      }
docs: Gets all data that should be available in a json representation.
  
  @return array an associative array of the available variables