code: @Override
    public void reduceToSegmentKeys() {
      if (segmentRegistration != null && size > 0) {
        int sizeCopy = size;
        String[] keyListCopy = keyList.clone();
        T1[] basicValueSumListCopy = basicValueSumList.clone();
        long[] basicValueNListCopy = basicValueNList.clone();
        size = 0;
        for (int i = 0; i < sizeCopy; i++) {
          if (segmentKeys.contains(keyListCopy[i])) {
            keyList[size] = keyListCopy[i];
            basicValueSumList[size] = basicValueSumListCopy[i];
            basicValueNList[size] = basicValueNListCopy[i];
            size++;
          }
        }
      }
    }
docs: /*
  (non-Javadoc)
  
  @see mtas.codec.util.collector.MtasDataCollector#reduceToSegmentKeys()