code: public int next() throws IOException {
          do {
              if (nextChildrenHit == nextNameTestHit) {
                  nextNameTestHit = hits2.next();
                  nextChildrenHit = hits1.next();
              } else if (nextNameTestHit < nextChildrenHit) {
                  nextNameTestHit = hits2.skipTo(nextChildrenHit);
              } else {
                  nextChildrenHit = hits1.skipTo(nextNameTestHit);
              }
          } while (nextChildrenHit > -1 && nextNameTestHit > -1
                  && nextNameTestHit != nextChildrenHit);
  
          int nextDoc = -1;
          if (nextChildrenHit == nextNameTestHit) {
              nextDoc = nextChildrenHit;
          }
          return nextDoc;
      }
docs: {@inheritDoc}