Github user kl0u commented on a diff in the pull request:
https://github.com/apache/flink/pull/5481#discussion_r171237136
--- Diff:
flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/KeyedStream.scala
---
@@ -79,7 +78,34 @@ class KeyedStream[T, K](javaStream: KeyedJavaStream[T,
K]) extends DataStream[T]
asScalaStream(javaStream.process(processFunction,
implicitly[TypeInformation[R]]))
}
-
+
+ /**
+ * Applies the given [[KeyedProcessFunction]] on the input stream,
thereby
+ * creating a transformed output stream.
+ *
+ * The function will be called for every element in the stream and can
produce
+ * zero or more output. The function can also query the time and set
timers. When
+ * reacting to the firing of set timers the function can emit yet more
elements.
+ *
+ * The function will be called for every element in the input streams
and can produce zero
+ * or more output elements. Contrary to the
[[DataStream#flatMap(FlatMapFunction)]]
+ * function, this function can also query the time and set timers. When
reacting to the firing
+ * of set timers the function can directly emit elements and/or register
yet more timers.
+ *
+ * @param keyedProcessFunction The [[KeyedProcessFunction]] that is
called for each element
+ * in the stream.
+ */
+ @PublicEvolving
+ def process[K, R: TypeInformation](
+ keyedProcessFunction: KeyedProcessFunction[K, T, R]): DataStream[R] = {
+
+ if (keyedProcessFunction == null) {
+ throw new NullPointerException("ProcessFunction must not be null.")
+ }
--- End diff --
The message now should be `"KeyedProcessFunction must not be null."`
---
