Github user myui commented on a diff in the pull request:
https://github.com/apache/incubator-hivemall/pull/124#discussion_r147900558
--- Diff: core/src/main/java/hivemall/tools/list/UDAFToOrderedList.java ---
@@ -406,6 +406,11 @@ void merge(@Nonnull List<Object> o_keyList, @Nonnull
List<Object> o_valueList) {
@Nonnull
Pair<List<Object>, List<Object>> drainQueue() {
+ if (queueHandler == null) {
+ return Pair.of((List<Object>) new ArrayList<Object>(),
+ (List<Object>) new ArrayList<Object>());
--- End diff --
better to return `null` following the way in other SQL standard functions.
`terminate()`, `terminatePartial()`, and `@Nonnull` annotation in
`drainQueue` also need to be changed.
---
