/** * @param set * @param restrictionSet * @return intersection of set (ConciseSet) and restrictionSet (if restrictionSet non-null & * non-empty); otherwise return set */ private static ExtendedSet<Integer> intersect( final ExtendedSet<Integer> set, final Set<Integer> restrictionSet) { if (restrictionSet != null && !restrictionSet.isEmpty()) { int prevSize = set.size(); FastSet intersection = new FastSet(set); intersection.retainAll(restrictionSet); log.debug( prevSize != 0 ? ("Size saving by retainAll = " + (((prevSize - intersection.size()) * 100) / prevSize)) + "%" : ""); return intersection; } return set; }