public K firstKey() {
    Entry<K, V> entry = firstEntry();
    if (entry == null) {
      throw new NoSuchElementException();
    } else {
      return entry.getKey();
    }
  }

  @Override
  @ParametricNullness
  public K lastKey() {
    Entry<K, V> entry = lastEntry();
    if (entry == null) {
      throw new NoSuchElementException();
    } else {
      return entry.getKey();
    }
  }

  @Override

    // completed after the timeout expired, and the message might be success.
    if (isDone()) {
      throw new TimeoutException(message + " but future completed as timeout expired");
    }
    throw new TimeoutException(message + " for " + futureToString);
  }

  @ParametricNullness

        if (timestampFormat == null) {
            timestampFormat = DEFAULT_BUILD_TIMESTAMP_FORMAT;
        }
        if (time == null) {
            time = new Date();
        }
        SimpleDateFormat dateFormat = new SimpleDateFormat(timestampFormat);
        dateFormat.setCalendar(new GregorianCalendar());
        dateFormat.setTimeZone(DEFAULT_BUILD_TIME_ZONE);
        formattedTimestamp = dateFormat.format(time);
    }

@GwtCompatible
@NullMarked
public abstract class TestEnumSetGenerator implements TestSetGenerator<AnEnum> {
  @Override
  public SampleElements<AnEnum> samples() {
    return new Enums();
  }

  @Override
  public Set<AnEnum> create(Object... elements) {
    AnEnum[] array = new AnEnum[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (AnEnum) e;
    }
    return create(array);
  }

            PluginContainer childContainer, PluginContainer parentContainer, boolean handleAsInheritance) {
        throw new UnsupportedOperationException();
    }

    public static List<Plugin> orderAfterMerge(
            List<Plugin> merged, List<Plugin> highPrioritySource, List<Plugin> lowPrioritySource) {
        throw new UnsupportedOperationException();
    }

    List<K> keys = new ArrayList<>(multimap().keySet());
    for (K key : keys) {
      resetCollection();
      assertTrue(multimap().asMap().remove(key) instanceof Set);
    }
  }

  @CollectionSize.Require(SEVERAL)
  public void testEquals() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k1(), v0()), mapEntry(k0(), v3()));
    Map<K, Collection<V>> expected = new HashMap<>();

    @Override
    public void visit(TokenVisitor visitor) {
        lexer.visit(new VisitorImpl(visitor));
    }

    private class VisitorImpl extends TokenVisitor {
        private final TokenVisitor visitor;
        private final LinkedList<String> elementStack = new LinkedList<String>();
        private final Map<String, String> attributes = new HashMap<String, String>();

        public VisitorImpl(TokenVisitor visitor) {

    }

    /**
     * Generates a new index name with timestamp suffix.
     *
     * @param configIndex the base index configuration name
     * @return the generated index name with timestamp
     */
    protected String generateNewIndexName(final String configIndex) {
        return configIndex + "." + new SimpleDateFormat(Constants.DOCUMENT_INDEX_SUFFIX_PATTERN).format(new Date());
    }

    /**

    /**
     * Lock object for synchronizing access to active thread count.
     */
    protected Object activeThreadCountLock = new Object();

    /**
     * Atomic counter for tracking the number of accesses made.
     */
    protected AtomicLong accessCount = new AtomicLong(0);

    /**
     * Current status of the crawler.
     */
    protected volatile CrawlerStatus status = CrawlerStatus.INITIALIZING;

            final List<UrlQueueImpl<Long>> targetList = new ArrayList<>();
            for (final UrlQueueImpl<Long> urlQueue : newUrlQueueList) {
                if (isNewUrl(urlQueue, urlQueueList)) {
                    targetList.add(urlQueue);
                }
            }
            urlQueueList.addAll(targetList);
        }

    }

    /**
     * Checks if a URL is new.
     *
     * @param urlQueue The URL queue.