code: public QueryNode[] getPredicates() {
          if (operands == null) {
              return EMPTY;
          } else {
              return (QueryNode[]) operands.toArray(new QueryNode[operands.size()]);
          }
      }
docs: Returns the predicate nodes for this location step. This method may
  also return a position predicate.
  @return the predicate nodes or an empty array if there are no predicates
  for this location step.