* @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
abstract class AbstractMultiset<E extends @Nullable Object> extends AbstractCollection<E>
    implements Multiset<E> {
  // Query Operations

  @Override
  public boolean isEmpty() {
    return entrySet().isEmpty();
  }

  @Override
  public boolean contains(@CheckForNull Object element) {
    return count(element) > 0;
  }

 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * <pre>{@code
 * final String name = ...;
 * inFlight.add(name);
 * ListenableFuture<Result> future = service.query(name);
 * future.addListener(new Runnable() {
 *   public void run() {
 *     processedCount.incrementAndGet();
 *     inFlight.remove(name);
 *     lastProcessed.set(name);
 *     logger.info("Done with {0}", name);

   * unprivileged user may return a resource accessible only to a privileged user making a similar
   * call. To prevent this problem, create a key object that includes all values that affect the
   * result of the query. Or use {@code LoadingCache.get(K)}, which lacks the ability to refer to
   * state other than that in the key.
   *
   * <p><b>Warning:</b> as with {@link CacheLoader#load}, {@code loader} <b>must not</b> return

@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@DoNotMock("Use ImmutableRangeSet or TreeRangeSet")
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public interface RangeSet<C extends Comparable> {

  // Query methods

  /** Determines whether any of this range set's member ranges contains {@code value}. */
  boolean contains(C value);

  /**

  }

  AbstractBiMap<V, K> makeInverse(Map<V, K> backward) {
    return new Inverse<>(backward, this);
  }

  void setInverse(AbstractBiMap<V, K> inverse) {
    this.inverse = inverse;
  }

  // Query Operations (optimizations)

  @Override
  public boolean containsValue(@CheckForNull Object value) {
    return inverse.containsKey(value);
  }

  // Modification Operations

  @CanIgnoreReturnValue

    }

    @VisibleForTesting
    OldConcurrentHashMultiset(ConcurrentMap<E, Integer> countMap) {
      checkArgument(countMap.isEmpty());
      this.countMap = countMap;
    }

    // Query Operations

    /**
     * Returns the number of occurrences of {@code element} in this multiset.
     *
     * @param element the element to look for

  @VisibleForTesting
  ConcurrentHashMultiset(ConcurrentMap<E, AtomicInteger> countMap) {
    checkArgument(countMap.isEmpty(), "the backing map (%s) must be empty", countMap);
    this.countMap = countMap;
  }

  // Query Operations

  /**
   * Returns the number of occurrences of {@code element} in this multiset.
   *
   * @param element the element to look for
   * @return the nonnegative number of occurrences of the element

     * e.g. hash codes adversarially designed to go into ascending table locations, which keeps
     * construction O(n) (as desired) but then can have O(n) queries later.
     *
     * <p>If this returns false, then no query can take more than O(log n).
     *
     * <p>Note that for a RegularImmutableSet with elements with truly random hash codes, contains

   */
  Collection<V> createCollection(@ParametricNullness K key) {
    return createCollection();
  }

  Map<K, Collection<V>> backingMap() {
    return map;
  }

  // Query Operations

  @Override
  public int size() {
    return totalSize;
  }

  @Override
  public boolean containsKey(@CheckForNull Object key) {
    return map.containsKey(key);
  }

          return Futures.immediateFuture(null);
        }
        // To avoid a race, make sure the refreshed value is set into loadingValueReference
        // *before* returning newValue from the cache query.
        return transform(
            newValue,
            newResult -> {
              LoadingValueReference.this.set(newResult);
              return newResult;
            },