public boolean isOrdering() {
    if (this.getOrder() != null && !this.getOrder().isEmpty()) {
      return true;
    }
    return false;
  }
Returns the sort order of the key columns.

@return null, which means ascending order for all key columns, or a String
        of the same length as key columns, that consists of only "+"
        (ascending order) and "-" (descending order).
ql/src/java/org/apache/hadoop/hive/ql/plan/ReduceSinkDesc.java