public function checkValueType($value = null)
    {
        if (!$value) {
            $value = $this->value;
        }
        $validator = Openbizx::getService(VALIDATE_SERVICE);
        switch ($this->type) {
            case "Number":
                $result = is_numeric($value);
                break;

            case "Text":
                $result = is_string($value);
                break;

            case "Date":
                $result = $validator->date($value);
                break;
            /*
              case "Datetime":    // zend doesn't support date time
              $result = $validator->date($value);
              break;

              case "Currency":
              $result = $validator->date($value);
              break;
             */
            case "Phone":
                $result = $validator->phone($value);
                break;

            default:
                $result = true;
                break;
        }

        return $result;
    }