`OAuth2PasswordRequestForm` is a class dependency that declares a form body with:

* The `username`.
* The `password`.
* An optional `scope` field as a big string, composed of strings separated by spaces.
* An optional `grant_type`.

/// tip

The OAuth2 spec actually *requires* a field `grant_type` with a fixed value of `password`, but `OAuth2PasswordRequestForm` doesn't enforce it.

 */
package org.apache.maven.repository;

import javax.inject.Inject;

import java.io.File;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.maven.SimpleLookup;
import org.apache.maven.api.ProducedArtifact;
import org.apache.maven.api.services.ArtifactManager;

            throws InvalidVersionSpecificationException {
        VersionRange versionRange = VersionRange.createFromVersionSpec(version);

        return artifactFactory.createDependencyArtifact(
                GROUP_ID, id, versionRange, "jar", null, scope, inheritedScope, optional);
    }

   *     in this instance of the Java virtual machine
   */
  public Optional<Charset> charset() {
    // racy single-check idiom, this is safe because Optional is immutable.
    Optional<Charset> local = parsedCharset;
    if (local == null) {
      String value = null;
      local = Optional.absent();
      for (String currentValue : parameters.get(CHARSET_ATTRIBUTE)) {
        if (value == null) {

   */
  private int findSuffixOfType(Optional<PublicSuffixType> desiredType) {
    int partsSize = parts.size();

    for (int i = 0; i < partsSize; i++) {
      String ancestorName = DOT_JOINER.join(parts.subList(i, partsSize));

      if (i > 0
          && matchesType(
              desiredType, Optional.fromNullable(PublicSuffixPatterns.UNDER.get(ancestorName)))) {
        return i - 1;

import org.codelibs.fess.opensearch.config.exentity.PathMapping;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.HtmlResponse;
import org.lastaflute.web.response.render.RenderData;

    @Nonnull
    DependencyScope getScope();

    /**
     * Returns whether the dependency is optional or mandatory.
     * Unlike {@link DependencyCoordinates}, the obligation of a {@code Dependency} is always present.
     * The value is computed during the dependencies collection phase.
     *
     * @return {@code true} if the dependency is optional, or {@code false} if mandatory
     * @see DependencyCoordinates#getOptional()
     */

import org.codelibs.fess.opensearch.config.exentity.FileConfig;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.HtmlResponse;
import org.lastaflute.web.response.render.RenderData;

    * Les valeurs de ce dictionnaire sont de type `float`.

#### `Optional`

Vous pouvez aussi utiliser `Optional` pour déclarer qu'une variable a un type, comme `str` mais qu'il est "optionnel" signifiant qu'il pourrait aussi être `None`.

{*../../docs_src/python_types/tutorial009.py hl[1,4] *}

import java.util.Locale;

import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.entity.SearchRequestParams;
import org.codelibs.fess.mylasta.action.FessUserBean;
import org.dbflute.optional.OptionalThing;

/**
 * Abstract base class for rank fusion searchers in the Fess search system.
 * Rank fusion searchers are responsible for executing search queries and