*
   * @since 11.0
   */
  public static <T> Optional<T> tryFind(Iterator<T> iterator, Predicate<? super T> predicate) {
    checkNotNull(iterator);
    checkNotNull(predicate);
    while (iterator.hasNext()) {
      T t = iterator.next();
      if (predicate.apply(t)) {
        return Optional.of(t);
      }
    }
    return Optional.absent();
  }

  /**

   *
   * @since 11.0
   */
  public static <T> Optional<T> tryFind(Iterator<T> iterator, Predicate<? super T> predicate) {
    checkNotNull(iterator);
    checkNotNull(predicate);
    while (iterator.hasNext()) {
      T t = iterator.next();
      if (predicate.apply(t)) {
        return Optional.of(t);
      }
    }
    return Optional.absent();
  }

  /**

 * Attempts to {@code put} an element into a full queue will result in the operation blocking;
 * attempts to {@code take} an element from an empty queue will similarly block.
 *
 * <p>This class supports an optional fairness policy for ordering waiting producer and consumer
 * threads. By default, this ordering is not guaranteed. However, a queue constructed with fairness

import org.codelibs.fess.mylasta.action.FessUserBean;
import org.codelibs.fess.rank.fusion.SearchResult.SearchResultBuilder;
import org.codelibs.fess.unit.UnitFessTestCase;
import org.dbflute.optional.OptionalThing;
import org.junit.jupiter.api.Test;

/**
 * Concurrency and thread-safety tests for RankFusionProcessor.
 * Tests the improvements made to thread safety using CopyOnWriteArrayList.
 */

Isso não é uma limitação do **FastAPI**, é parte do protocolo HTTP.

///

## Upload de Arquivo Opcional { #optional-file-upload }

Você pode tornar um arquivo opcional usando anotações de tipo padrão e definindo um valor padrão de `None`:

{* ../../docs_src/request_files/tutorial001_02_an_py310.py hl[9,17] *}

  /** Returns a plan to attempt. */
  @Throws(IOException::class)
  fun plan(): Plan

  /**
   * Returns true if there's more route plans to try.
   *
   * @param failedConnection an optional connection that was resulted in a failure. If the failure
   *     is recoverable, the connection's route may be recovered for the retry.
   */
  fun hasNext(failedConnection: RealConnection? = null): Boolean

  /**

     * @param wildcard
     *            wildcard pattern for filtering servers
     * @param searchAttributes
     *            attributes to search for
     * @param filter
     *            optional resource name filter
     * @throws CIFSException
     *            if enumeration fails
     */

     * @throws PACDecodingException if a PAC decoding error occurs
     */
    @Test
    void testGettersWithNull() throws IOException, PACDecodingException {
        // Build a token with no optional fields
        ASN1EncodableVector vector = new ASN1EncodableVector();
        DERSequence sequence = new DERSequence(vector);
        byte[] encoded = new DERTaggedObject(false, BERTags.APPLICATION, 1, sequence).getEncoded();

```
http://127.0.0.1:8000/items/?skip=0&limit=10
```

但如果你改為造訪：

```
http://127.0.0.1:8000/items/?skip=20
```

函式中的參數值會是：

* `skip=20`：因為你在 URL 中設定了它
* `limit=10`：因為那是預設值

## 選用參數 { #optional-parameters }

同樣地，你可以將預設值設為 `None` 來宣告選用的查詢參數：

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

在這種情況下，函式參數 `q` 為選用，且預設為 `None`。

/// check | 注意

import org.codelibs.fess.exception.UserRoleLoginException;
import org.codelibs.fess.helper.CrawlingConfigHelper;
import org.codelibs.fess.helper.PermissionHelper;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.di.util.LdiFileUtil;
import org.lastaflute.web.login.LoginManager;
import org.lastaflute.web.response.ActionResponse;
import org.lastaflute.web.ruts.process.ActionRuntime;