return backingMap.getEntry(entryIndex);
      }
    };
  }

  /** Allocation-free implementation of {@code target.addAll(this)}. */
  void addTo(Multiset<? super E> target) {
    checkNotNull(target);
    for (int i = backingMap.firstIndex(); i >= 0; i = backingMap.nextIndex(i)) {
      target.add(backingMap.getKey(i), backingMap.getValue(i));
    }
  }

  @Override
  final int distinctElements() {

  /** Standard constructor. */
  protected AbstractMapBasedMultiset(Map<E, Count> backingMap) {
    checkArgument(backingMap.isEmpty());
    this.backingMap = backingMap;
  }

  /** Used during deserialization only. The backing map must be empty. */
  void setBackingMap(Map<E, Count> backingMap) {
    this.backingMap = backingMap;
  }

  // Required Implementations

  /**
   * {@inheritDoc}
   *

  ConcurrentMap<String, AtomicInteger> backingMap;
  ConcurrentHashMultiset<String> multiset;

  @SuppressWarnings("unchecked")
  @Override
  protected void setUp() {
    backingMap = mock(ConcurrentMap.class);
    when(backingMap.isEmpty()).thenReturn(true);

    multiset = ConcurrentHashMultiset.create(backingMap);
  }

  public void testCount_elementPresent() {

    @Override
    public int add(E element, int occurrences) {
      checkArgument(occurrences >= 0);
      Integer frequency = backingMap.getOrDefault(element, 0);
      if (occurrences == 0) {
        return frequency;
      }
      checkArgument(occurrences <= Integer.MAX_VALUE - frequency);
      backingMap.put(element, frequency + occurrences);
      return frequency;
    }

    @Override
    Iterator<E> elementIterator() {

    private final Map<Class<? extends @NonNull B>, B> backingMap;

    SerializedForm(Map<Class<? extends @NonNull B>, B> backingMap) {
      this.backingMap = backingMap;
    }

    Object readResolve() {
      return create(backingMap);
    }

    private static final long serialVersionUID = 0;
  }

    private final NavigableMap<K, V> backingMap;

    StandardImplForwardingNavigableMap(NavigableMap<K, V> backingMap) {
      this.backingMap = backingMap;
    }

    @Override
    protected NavigableMap<K, V> delegate() {
      return backingMap;
    }

    @Override
    public boolean containsKey(Object key) {
      return standardContainsKey(key);

      int expectedRows, int expectedCellsPerRow) {
    checkNonnegative(expectedCellsPerRow, "expectedCellsPerRow");
    Map<R, Map<C, V>> backingMap = Maps.newLinkedHashMapWithExpectedSize(expectedRows);
    return new HashBasedTable<>(backingMap, new Factory<C, V>(expectedCellsPerRow));
  }

  /**
   * Creates a {@code HashBasedTable} with the same mappings as the specified table.
   *

      int expectedRows, int expectedCellsPerRow) {
    checkNonnegative(expectedCellsPerRow, "expectedCellsPerRow");
    Map<R, Map<C, V>> backingMap = Maps.newLinkedHashMapWithExpectedSize(expectedRows);
    return new HashBasedTable<>(backingMap, new Factory<C, V>(expectedCellsPerRow));
  }

  /**
   * Creates a {@code HashBasedTable} with the same mappings as the specified table.
   *

   * RowSortedTable subinterface with the revised methods?
   */

  StandardRowSortedTable(
      SortedMap<R, Map<C, V>> backingMap, Supplier<? extends Map<C, V>> factory) {
    super(backingMap, factory);
  }

  private SortedMap<R, Map<C, V>> sortedBackingMap() {
    return (SortedMap<R, Map<C, V>>) backingMap;
  }

  /**
   * {@inheritDoc}
   *

    checkArgument(backingMap.isEmpty());
    checkNotNull(factory);
    // TODO(jlevy): Wrap factory to validate that the supplied maps are empty?
    return new StandardTable<>(backingMap, factory);
  }

  /**
   * Returns a view of a table where each value is transformed by a function. All other properties
   * of the table, such as iteration order, are left intact.
   *