code: public List<QueryImpl> getDependingQueries() {
          if (dependingQueries == null) {
              dependingQueries = usedQueries == null ? Collections.<QueryImpl>emptyList() : collectDependingQueries(new LinkedList<QueryImpl>());
          }
          return dependingQueries;
      }
docs: Returns the lists of queries from which this rule (or query) depends on ordered
  by their relative dependencies, e.g. if R1 -> A -> B -> C (where the letter are queries)
  it will return [C, B, A]