@J2ktIncompatible
  @GwtIncompatible
    Object writeReplace() {
    Map<C, Integer> columnKeyToIndex = Maps.indexMap(columnKeySet());
    int[] cellColumnIndices = new int[cellSet().size()];
    int i = 0;
    for (Cell<R, C, V> cell : cellSet()) {
      // requireNonNull is safe because the cell exists in the table.
      cellColumnIndices[i++] = requireNonNull(columnKeyToIndex.get(cell.getColumnKey()));
    }

      }
    }
  }

  ImmutableTable() {}

  @Override
  public ImmutableSet<Cell<R, C, V>> cellSet() {
    return (ImmutableSet<Cell<R, C, V>>) super.cellSet();
  }

  @Override
  abstract ImmutableSet<Cell<R, C, V>> createCellSet();

  @Override
  final UnmodifiableIterator<Cell<R, C, V>> cellIterator() {

   * cell views, as returned by {@link #cellSet}, are equal.
   */
  @Override
  boolean equals(@Nullable Object obj);

  /**
   * Returns the hash code for this table. The hash code of a table is defined as the hash code of
   * its cell view, as returned by {@link #cellSet}.
   */
  @Override
  int hashCode();

  // Mutators

      /* TODO: verify that the Collection is also synchronized? */
      return delegate.values();
    }

    @Override
    public Set<Cell<R, C, V>> cellSet() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.cellSet();
    }

    @Override
    public Map<R, V> column(C columnKey) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.column(columnKey);
    }

      }
    }
  }

  ImmutableTable() {}

  @Override
  public ImmutableSet<Cell<R, C, V>> cellSet() {
    return (ImmutableSet<Cell<R, C, V>>) super.cellSet();
  }

  @Override
  abstract ImmutableSet<Cell<R, C, V>> createCellSet();

  @Override
  final UnmodifiableIterator<Cell<R, C, V>> cellIterator() {

      /* TODO: verify that the Collection is also synchronized? */
      return delegate.values();
    }

    @Override
    public Set<Cell<R, C, V>> cellSet() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.cellSet();
    }

    @Override
    public Map<R, V> column(C columnKey) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.column(columnKey);
    }

                columnFunction.apply(input),
                valueFunction.apply(input),
                mergeFunction),
        (table1, table2) -> {
          for (Table.Cell<R, C, V> cell2 : table2.cellSet()) {
            mergeTables(
                table1, cell2.getRowKey(), cell2.getColumnKey(), cell2.getValue(), mergeFunction);
          }
          return table1;
        });
  }

                columnFunction.apply(input),
                valueFunction.apply(input),
                mergeFunction),
        (table1, table2) -> {
          for (Table.Cell<R, C, V> cell2 : table2.cellSet()) {
            mergeTables(
                table1, cell2.getRowKey(), cell2.getColumnKey(), cell2.getValue(), mergeFunction);
          }
          return table1;
        });
  }

    validateViewOrdering(original, built);
  }

  private static <R, C, V> void validateViewOrdering(Table<R, C, V> original, Table<R, C, V> copy) {
    assertThat(copy.cellSet()).containsExactlyElementsIn(original.cellSet()).inOrder();
    assertThat(copy.rowKeySet()).containsExactlyElementsIn(original.rowKeySet()).inOrder();
    assertThat(copy.values()).containsExactlyElementsIn(original.values()).inOrder();
  }

    @Override
    Iterator<Cell<C, R, V>> cellIterator() {
      return Iterators.transform(original.cellSet().iterator(), Tables::transposeCell);
    }

    @Override
    @GwtIncompatible // Spliterator
    Spliterator<Cell<C, R, V>> cellSpliterator() {
      return CollectSpliterators.map(
          original.cellSet().spliterator(),
          Spliterator.DISTINCT | Spliterator.NONNULL,
          Tables::transposeCell);