assertTrue(validator.determineValid(null));
        assertTrue(validator.determineValid(""));
        assertTrue(validator.determineValid(" "));
        assertTrue(validator.determineValid("   "));
        assertTrue(validator.determineValid("\t"));
        assertTrue(validator.determineValid("\n"));
    }

    @Test
    public void test_initialize() {

import jakarta.validation.ConstraintViolation;
import jakarta.validation.Validation;
import jakarta.validation.Validator;
import jakarta.validation.ValidatorFactory;
import jakarta.validation.groups.Default;

public class CronExpressionTest extends UnitFessTestCase {

    private Validator validator;

    @Override
    protected void setUp(TestInfo testInfo) throws Exception {
        super.setUp(testInfo);

public class CustomSizeValidatorTest extends UnitFessTestCase {

    private CustomSizeValidator validator;

    @Override
    protected void setUp(TestInfo testInfo) throws Exception {
        super.setUp(testInfo);
        validator = new CustomSizeValidator();
    }

    @Test
    public void test_constructor() {
        assertNotNull(validator);
    }

    @Test
    public void test_isValid_nullValue() {

import kotlinx.validation.ApiValidationExtension
import kotlinx.validation.KotlinApiBuildTask
import kotlinx.validation.KotlinApiCompareTask

plugins {
  id("com.vanniktech.maven.publish.base")
  id("binary-compatibility-validator")
}

configure<MavenPublishBaseExtension> {
  publishToMavenCentral(automaticRelease = true)
  signAllPublications()
  pom {
    name.set(project.name)

In those cases, you can use a **custom validator function** that is applied after the normal validation (e.g. after validating that the value is a `str`).

You can achieve that using [Pydantic's `AfterValidator`](https://docs.pydantic.dev/latest/concepts/validators/#field-after-validator) inside of `Annotated`.

/// tip

    # For the test client
    "httpx >=0.23.0,<1.0.0",
    # For templates
    "jinja2 >=3.1.5",
    # For forms and file uploads
    "python-multipart >=0.0.18",
    # To validate email fields
    "email-validator >=2.0.0",
    # Uvicorn with uvloop
    "uvicorn[standard] >=0.12.0",
    # # Settings management
    "pydantic-settings >=2.0.0",
    # # Extra Pydantic data types
    "pydantic-extra-types >=2.0.0",
]

            logger.warning(
                "email-validator not installed, email fields will be treated as str.\n"
                "To install, run: pip install email-validator"
            )
            return str(v)

        @classmethod
        def _validate(cls, __input_value: Any, _: Any) -> str:
            logger.warning(
                "email-validator not installed, email fields will be treated as str.\n"

        @Override
        public String getConverterPackageName() {
            return "converter";
        }

        @Override
        public String getValidatorPackageName() {
            return "validator";
        }

        @Override
        public String getInterceptorPackageName() {
            return "interceptor";
        }

        @Override
        public String getHelperPackageName() {

errors.header = <ul class="has-error">
errors.footer = </ul>
errors.prefix = <li><i class="fa fa-exclamation-circle"></i>
errors.suffix = </li>
# ----------------------------------------------------------
# Javax Validator
# ---------------
constraints.AssertFalse.message = {item} musi być fałszywe.
constraints.AssertTrue.message = {item} musi być prawdziwe.
constraints.DecimalMax.message = {item} musi być mniejsze niż {value}.

後に例を用いて宣言を学ぶ際に、追加情報を追加する方法を学べます。

/// warning | 注意

`Field`に渡された追加のキーは、結果として生成されるアプリケーションのOpenAPIスキーマにも含まれます。
これらのキーは必ずしもOpenAPI仕様の一部であるとは限らないため、例えば[OpenAPI validator](https://validator.swagger.io/)などの一部のOpenAPIツールは、生成されたスキーマでは動作しない場合があります。

///

## まとめ { #recap }

Pydanticの`Field`を使用して、モデルの属性に追加のバリデーションやメタデータを宣言することができます。