public static HiveDecimalWritable plus(HiveDecimalWritable t1, HiveDecimalWritable t2) {
    HiveDecimalWritable result = new HiveDecimalWritable(t1);
    result.mutateAdd(t2);
    return result;
  }
VectorPTFEvaluatorHelper is a helper class for vector ptf operations.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/ptf/VectorPTFEvaluatorHelper.java