Comparator<TestDatum> comparator = Comparator.comparing(d -> d.letter);

    // When elements compare as equal (both C's have same letter), our merge should always return C1
    // before C2, since C1 is from the first iterator.

    Iterator<TestDatum> merged =
        Iterators.mergeSorted(ImmutableList.of(left.iterator(), right.iterator()), comparator);

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

import java.io.InputStream;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.lang.StringUtil;

final class AllEqualOrdering extends Ordering<@Nullable Object> implements Serializable {
  static final AllEqualOrdering INSTANCE = new AllEqualOrdering();

  @Override
  @SuppressWarnings("UnusedVariable") // intentionally weird Comparator
  public int compare(@Nullable Object left, @Nullable Object right) {
    return 0;
  }

  @Override
  public <E extends @Nullable Object> List<E> sortedCopy(Iterable<E> iterable) {

    }

    @Override
    SortedSet<E> delegate() {
      return (SortedSet<E>) super.delegate();
    }

    @Override
    public @Nullable Comparator<? super E> comparator() {
      synchronized (mutex) {
        return delegate().comparator();
      }
    }

    @Override
    public SortedSet<E> subSet(E fromElement, E toElement) {
      synchronized (mutex) {

   * created multimaps.
   *
   * @since 2.0
   */
  @DoNotMock
  public static class Builder<K, V> {
    @Nullable Map<K, ImmutableCollection.Builder<V>> builderMap;
    @Nullable Comparator<? super K> keyComparator;
    @Nullable Comparator<? super V> valueComparator;
    int expectedValuesPerKey = ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY;

    /**

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicInteger;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Map;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import org.jspecify.annotations.Nullable;

    assertEquals(42, queue.maximumSize);
    assertSame(SOME_COMPARATOR, queue.comparator());
  }

  // TODO: tests that check the weird interplay between expected size,
  // maximum size, size of initial contents, default capacity...

  private static void checkNatural(MinMaxPriorityQueue<Integer> queue) {
    assertSame(Ordering.natural(), queue.comparator());
  }

  public static <T extends @Nullable Object> UnmodifiableIterator<T> mergeSorted(
      Iterable<? extends Iterator<? extends T>> iterators, Comparator<? super T> comparator) {
    checkNotNull(iterators, "iterators");
    checkNotNull(comparator, "comparator");

    return new MergingIterator<>(iterators, comparator);
  }

  /**
   * An iterator that performs a lazy N-way merge, calculating the next value each time the iterator

   * array as the lesser. For example, {@code [] < ['a'] < ['a', 'b'] < ['b']}.
   *
   * <p>The returned comparator is inconsistent with {@link Object#equals(Object)} (since arrays
   * support only identity equality), but it is consistent with {@link Arrays#equals(char[],
   * char[])}.
   *
   * @since 2.0
   */
  public static Comparator<char[]> lexicographicalComparator() {
    return LexicographicalComparator.INSTANCE;
  }