code: public BitSet getMatchingParameters(BitSet nullArgSet) {
          BitSet result = new BitSet();
          for (int i = 0; i < 32; ++i) {
              result.set(i, nullArgSet.get(i) && hasProperty(i));
          }
          return result;
      }
docs: Given a bitset of null arguments passed to the method represented by this
  property, return a bitset indicating which null arguments correspond to
  an non-null param.
  
  @param nullArgSet
  bitset of null arguments
  @return bitset intersecting null arguments and non-null params