}

    @Nullable
    public static Path findRoot(Path topDirectory) {
        requireNonNull(topDirectory, "topDirectory");
        Path rootDirectory =
                ServiceLoader.load(RootLocator.class).iterator().next().findRoot(topDirectory);
        if (rootDirectory != null) {
            return getCanonicalPath(rootDirectory);
        }
        return null;
    }

    @Nonnull

    assertThat(DoubleMath.mean(ImmutableList.of(11, -22, 44, -88).iterator()))
        .isWithin(1.0e-10)
        .of(-13.75);
    assertThat(DoubleMath.mean(ImmutableList.of(11).iterator())).isWithin(1.0e-10).of(11);
    assertThrows(
        IllegalArgumentException.class,
        () -> DoubleMath.mean(ImmutableList.<Integer>of().iterator()));
  }

  @GwtIncompatible // DoubleMath.mean

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import org.jspecify.annotations.Nullable;

/**
 * An Iterator implementation which draws elements from a queue, removing them from the queue as it
 * iterates. This class is not thread safe.
 */
@GwtCompatible
final class ConsumingQueueIterator<T extends @Nullable Object> extends AbstractIterator<T> {
  private final Queue<T> queue;

import org.jspecify.annotations.Nullable;

/**
 * A {@code Multiset} implementation with predictable iteration order. Its iterator orders elements
 * according to when the first occurrence of the element was added. When the multiset contains
 * multiple instances of an element, those instances are consecutive in the iteration order. If all
 * occurrences of an element are removed, after which that element is added to the multiset, the

            return parent.isEmpty();
        }

        public boolean contains(final Object o) {
            return parent.contains(o);
        }

        public Iterator<E> iterator() {
            return parent.iterator();
        }

        public Object[] toArray() {
            return parent.toArray();
        }

        public <T> T[] toArray(final T[] a) {

        return new AbstractSet<>() {
            @Override
            public Iterator<Entry<String, String>> iterator() {
                return new Iterator<>() {
                    final Iterator<Entry<String, String>> keyIterator =
                            storage.entrySet().iterator();

                    @Override
                    public boolean hasNext() {

        return new AbstractSet<>() {
            @Override
            public Iterator<Entry<String, String>> iterator() {
                return new Iterator<>() {
                    final Iterator<Entry<String, String>> keyIterator =
                            storage.entrySet().iterator();

                    @Override
                    public boolean hasNext() {

  ImmutableMapKeySet(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override
  public UnmodifiableIterator<K> iterator() {
    return map.keyIterator();
  }

  @Override
  public boolean contains(@Nullable Object object) {
    return map.containsKey(object);
  }

  @Override
  K get(int index) {

 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;

/**
 * A generator that relies on a preexisting generator for most of its work. For example, a derived
 * iterator generator may delegate the work of creating the underlying collection to an inner
 * collection generator.
 *
 * <p>{@code GwtTestSuiteGenerator} expects every {@code DerivedIterator} implementation to provide

 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;

/**
 * A generator that relies on a preexisting generator for most of its work. For example, a derived
 * iterator generator may delegate the work of creating the underlying collection to an inner
 * collection generator.
 *
 * <p>{@code GwtTestSuiteGenerator} expects every {@code DerivedIterator} implementation to provide