class BooleanColumn extends AbstractColumn<BooleanColumn, Boolean> implements BooleanFilterSpec<Selection>,
        BooleanMapUtils,
        CategoricalColumn<Boolean>,
        BooleanFillers<BooleanColumn>,
        BooleanFilters {

  @Override
  public int countUnique() {
    ByteSet count = new ByteOpenHashSet(3);
    for (byte next : data) {
      count.add(next);
    }
    return count.size();
  }

  private  BooleanColumn(String name, ByteArrayList values);

}