eZ\Publish\Core\FieldType\TextLine\Type::validate PHP Method

    public function validate(FieldDefinition $fieldDefinition, SPIValue $fieldValue)
    {
        $validationErrors = array();
        if ($this->isEmptyValue($fieldValue)) {
            return $validationErrors;
        }
        $validatorConfiguration = $fieldDefinition->getValidatorConfiguration();
        $constraints = isset($validatorConfiguration['StringLengthValidator']) ? $validatorConfiguration['StringLengthValidator'] : array();
        if (isset($constraints['maxStringLength']) && $constraints['maxStringLength'] !== false && $constraints['maxStringLength'] !== 0 && strlen($fieldValue->text) > $constraints['maxStringLength']) {
            $validationErrors[] = new ValidationError('The string can not exceed %size% character.', 'The string can not exceed %size% characters.', array('%size%' => $constraints['maxStringLength']), 'text');
        }
        if (isset($constraints['minStringLength']) && $constraints['minStringLength'] !== false && $constraints['minStringLength'] !== 0 && strlen($fieldValue->text) < $constraints['minStringLength']) {
            $validationErrors[] = new ValidationError('The string can not be shorter than %size% character.', 'The string can not be shorter than %size% characters.', array('%size%' => $constraints['minStringLength']), 'text');
        }
        return $validationErrors;
    }