@Override
  protected OrcStruct createStructObject(Object previous, List<TypeInfo> childrenTypes) {
    int numChildren = childrenTypes.size();
    if (previous == null || !(previous instanceof OrcStruct)) {
      return new OrcStruct(numChildren);
    }
    OrcStruct result = (OrcStruct) previous;
    result.setNumFields(numChildren);
    return result;
  }
BatchToRowReader that returns the rows readable by ORC IOs.
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcOiBatchToRowReader.java