class AnswerMetadataUtil {

  @VisibleForTesting
  static Set<String> computeEmptyColumns(TableAnswerElement table) {
    return table.getMetadata().toColumnMap().keySet().stream()
        .filter(column -> table.getRowsList().stream().allMatch(row -> !row.hasNonNull(column)))
        .collect(ImmutableSet.toImmutableSet());
  }

  private  AnswerMetadataUtil();

}