code: static IntTupleIncrementor incrementor(Order order)
      {
          if (order == null)
          {
              return null;
          }
          switch (order)
          {
              case LEXICOGRAPHICAL:
                  return lexicographicalIncrementor();
              case COLEXICOGRAPHICAL:
                  return colexicographicalIncrementor();
              default:
                  break;
          }
          return null;
      }
docs: Returns an {@link IntTupleIncrementor} that increments tuples in the
  given {@link Order}. If the given {@link Order} is <code>null</code>,
  then <code>null</code> will be returned.
  
  @param order The {@link Order}
  @return The {@link IntTupleIncrementor}
  
  @see #lexicographicalIncrementor()
  @see #colexicographicalIncrementor()