public boolean isTagPositionRolledUp(final int tagPosition) {
        if (tagPosition < 0) {
            throw new RuntimeException("Field position cannot be less than zero");
        }

        return getTagPositions().contains(tagPosition);
    }
@return The bit mask as a list of field positions where the field is
rolled up, e.g. [0,2] indicates that the fields at position 0 and
2 are rolled up
stroom-statistics/stroom-statistics-impl-sql/src/main/java/stroom/statistics/impl/sql/rollup/RollUpBitMask.java