code: private SpdStat getSpdStat() {
          myValue.reset(false);
          for (int i = 0; i < members.size(); i++) {
              Object member = members.get(i);
              if (member == null)
                  continue;
              if (member instanceof SpdStat) {
                  myValue.combine((SpdStat) member);
              } else { // SpdStatAggregate
                  myValue.combine(((SpdStatAggregate) member).getSpdStat());
              }
          }
          return myValue;
      }
docs: Recursive.