src/Schema.php
protected function validateString(&$value, array $field, Validation $validation) {
        if (is_string($value)) {
            $validType = true;
        } elseif (is_numeric($value)) {
            $value = (string)$value;
            $validType = true;
        } else {
            $validType = false;
        }
        return $validType;
    }
protected function validateString(&$value, array $field, Validation $validation) {
        if (is_string($value)) {
            $validType = true;
        } elseif (is_numeric($value)) {
            $value = (string)$value;
            $validType = true;
        } else {
            $validType = false;
        }
        return $validType;
    }
Validate a string.

@param mixed &$value The value to validate.
@param array $field The field definition.
@param Validation $validation The validation results to add.
@return bool Returns true if {@link $value} is valid or false otherwise.