validate method

@override String? validate(String? valueToValidate)

Returns validation error messages as a single string joined with the newline character if the input valueToValidate does not pass validation and returns null otherwise.

Implementation

@override
String? validate(String? valueToValidate) {
  String? result;

  for (HoverValidationRule rule in _validationRules) {
    String? validationMessage = rule.validate(valueToValidate!);
    if (validationMessage != null && validationMessage.isNotEmpty) {
      if (result != null) {
        result += "\n" + validationMessage;
      } else {
        result = validationMessage;
      }
    }
  }

  return result;
}