code: public int getIndexOfColumn(String columnName) {
          Integer idx = columnNamesIndex.get(columnName);
          if (idx == null)
              throw new NoSuchElementException("Unknown column: \"" + columnName + "\"");
          return idx;
      }
docs: Returns the index for the given
  column name
  @param columnName the column name to get the
  index for
  @return the index of the given column name
  for the schema