enumConstantCache = new WeakHashMap<>();

  private static <T extends Enum<T>> Map<String, WeakReference<? extends Enum<?>>> populateCache(
      Class<T> enumClass) {
    Map<String, WeakReference<? extends Enum<?>>> result = new HashMap<>();
    for (T enumInstance : EnumSet.allOf(enumClass)) {
      result.put(enumInstance.name(), new WeakReference<Enum<?>>(enumInstance));

      enumConstantCache = new WeakHashMap<>();

  private static <T extends Enum<T>> Map<String, WeakReference<? extends Enum<?>>> populateCache(
      Class<T> enumClass) {
    Map<String, WeakReference<? extends Enum<?>>> result = new HashMap<>();
    for (T enumInstance : EnumSet.allOf(enumClass)) {
      result.put(enumInstance.name(), new WeakReference<Enum<?>>(enumInstance));

  // Wrapper of EnumMultiset factory methods, because we need to skip create(Class).
  // create(Enum1.class) is equal to create(Enum2.class) but testEquals() expects otherwise.
  // For the same reason, we need to skip create(Iterable, Class).
  private static class EnumMultisetFactory {
    @Keep // used reflectively by testEquals
    public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
      return EnumMultiset.create(elements);

  // Wrapper of EnumMultiset factory methods, because we need to skip create(Class).
  // create(Enum1.class) is equal to create(Enum2.class) but testEquals() expects otherwise.
  // For the same reason, we need to skip create(Iterable, Class).
  private static class EnumMultisetFactory {
    @Keep // used reflectively by testEquals
    public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
      return EnumMultiset.create(elements);

    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).hasValue(TestEnum.POODLE);

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).isPresent();
    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).isPresent();
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).isPresent();

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).hasValue(TestEnum.CHEETO);

    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).hasValue(TestEnum.POODLE);

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).isPresent();
    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).isPresent();
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).isPresent();

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).hasValue(TestEnum.CHEETO);

          .that(returnType.getComponentType())
          .isEqualTo(annotationClass.getDeclaringClass());
    }
  }

  // This is public so that tests for Feature enums we haven't yet imagined
  // can reuse it.
  public static <E extends Enum<?> & Feature<?>> void assertGoodFeatureEnum(
      Class<E> featureEnumClass) {
    Class<?>[] classes = featureEnumClass.getDeclaredClasses();
    for (Class<?> containedClass : classes) {

전달된 태그들은 OpenAPI의 스키마에 추가되며, 자동 문서 인터페이스에서 사용됩니다:

<img src="/img/tutorial/path-operation-configuration/image01.png">

### Enum을 사용한 태그 { #tags-with-enums }

큰 애플리케이션이 있다면, **여러 태그**가 쌓이게 될 수 있고, 관련된 *경로 처리*에 항상 **같은 태그**를 사용하는지 확인하고 싶을 것입니다.

이런 경우에는 태그를 `Enum`에 저장하는 것이 합리적일 수 있습니다.

**FastAPI**는 일반 문자열과 동일한 방식으로 이를 지원합니다:

{* ../../docs_src/path_operation_configuration/tutorial002b_py310.py hl[1,8:10,13,18] *}

          .that(returnType.getComponentType())
          .isEqualTo(annotationClass.getDeclaringClass());
    }
  }

  // This is public so that tests for Feature enums we haven't yet imagined
  // can reuse it.
  public static <E extends Enum<?> & Feature<?>> void assertGoodFeatureEnum(
      Class<E> featureEnumClass) {
    Class<?>[] classes = featureEnumClass.getDeclaredClasses();
    for (Class<?> containedClass : classes) {

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Enums;
import java.util.List;
import java.util.Set;
import org.jspecify.annotations.NullMarked;

/**
 * An abstract TestSetGenerator for generating sets containing enum values.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked