this.validator = validator;
    }
  }

  private enum Result {
    SUCCESS(immediateFuture(new Object())),
    FAILURE(immediateFailedFuture(new Exception()));

    final Future<Object> future;

    Result(Future<Object> result) {
      this.future = result;
    }
  }

  private enum ExceptionType {
    CHECKED(IOException.class),
    UNCHECKED(RuntimeException.class);

 * serialization of funnels. When possible, it is recommended that funnels be implemented as a
 * single-element enum to maintain serialization guarantees. See Effective Java (2nd Edition), Item
 * 3: "Enforce the singleton property with a private constructor or an enum type". For example:
 *
 * {@snippet :
 * public enum PersonFunnel implements Funnel<Person> {
 *   INSTANCE;
 *   public void funnel(Person person, PrimitiveSink into) {

package org.gradle.test;

public enum JavaEnum {
    A, B

### Crie uma classe `Enum` { #create-an-enum-class }

Importe `Enum` e crie uma subclasse que herde de `str` e de `Enum`.

Ao herdar de `str`, a documentação da API saberá que os valores devem ser do tipo `string` e poderá renderizá-los corretamente.

package common

enum class FlakyTestStrategy {
    INCLUDE,
    EXCLUDE,
    ONLY,
    ;

    override fun toString() = name.lowercase()

 *
 * @author Jared Levy
 */
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
final class ImmutableEnumSet<E extends Enum<E>> extends ImmutableSet<E> {
  static <E extends Enum<E>> ImmutableSet<E> asImmutable(EnumSet<E> set) {
    switch (set.size()) {
      case 0:
        return ImmutableSet.of();
      case 1:
        return ImmutableSet.of(getOnlyElement(set));

 *
 */
public interface ExecutionEvent {

    /**
     * The possible types of execution events.
     *
     * Note: do not modify this enum, or, make sure that this enum and
     * {@link org.apache.maven.api.EventType} have same elements in same order.
     */
    enum Type {
        ProjectDiscoveryStarted,
        SessionStarted,
        SessionEnded,
        ProjectSkipped,
        ProjectStarted,

package org.gradle.test;

import org.gradle.test.sub2.Sub2Interface;

public class JavaClassWithInnerTypes implements Sub2Interface {
    /**
     * This is an inner enum.
     */
    enum InnerEnum {
    }

    /**
     * This is an inner class.
     */
    static class InnerClass {
        InnerEnum getEnumProp() { return null; }

        /**
         * This is an inner inner class.
         */

    List<String> temp = new ArrayList<>();
    for (Feature<?> feature : features) {
      Object featureAsObject = feature; // to work around bogus JDK warning
      if (featureAsObject instanceof Enum) {
        Enum<?> f = (Enum<?>) featureAsObject;
        temp.add(f.getDeclaringClass().getSimpleName() + "." + feature);
      } else {
        temp.add(feature.toString());
      }
    }
    return temp.toString();
  }

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.crawler;

/**
 * Enum representing the status of a crawler.
 * It can be INITIALIZING, RUNNING, or DONE.
 */
public enum CrawlerStatus {
    /**
     * The crawler is initializing.
     */
    INITIALIZING,

    /**
     * The crawler is currently running.
     */