gistfile1.java

    private boolean updateEntrySet(BitSet entrySet, BitSet exitSet, 
                                   BitSet useBeforeDef, BitSet notDef) {
        int card = entrySet.cardinality();
        entrySet.or(exitSet);
        entrySet.and(notDef);
        entrySet.or(useBeforeDef);
        return entrySet.cardinality() != card;
    }