Github user sunjincheng121 commented on a diff in the pull request:
https://github.com/apache/flink/pull/3993#discussion_r118806216
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/functions/utils/UserDefinedFunctionUtils.scala
---
@@ -329,6 +330,21 @@ object UserDefinedFunctionUtils {
}
/**
+ * Returns the value (boolean) of AggregateFunction#requiresOver() that
indicates if this
+ * AggregateFunction can only be used for over window aggregate. If
method requiresOver is not
+ * provided, return false as default value.
+ */
+ def getRequiresOverConfig(aggregateFunction: AggregateFunction[_, _]):
Boolean = {
+ try {
+ val method: Method =
aggregateFunction.getClass.getMethod("requiresOver")
--- End diff --
I think the method supported to check the `modifiers` as well. Just like
`checkAndExtractMethods`'s method logic. So I suggest using
`checkAndExtractMethods` directly. Changes as follows:
1. Add boolean param for `checkAndExtractMethods`
2. Change this method looks like :
```
val methods = checkAndExtractMethods(aggregateFunction, "requiresOver2",
true)
if (methods.isEmpty || methods.length > 1) {
return false
} else {
methods(0).invoke(aggregateFunction).asInstanceOf[Boolean]
}
```
In addition, If you want to strictly check, you can check the input
parameters and return type. What do you think?
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