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https://issues.apache.org/jira/browse/FLINK-2184?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15573303#comment-15573303
]
ASF GitHub Bot commented on FLINK-2184:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/1975#discussion_r83319084
--- Diff:
flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/WindowedStream.scala
---
@@ -362,38 +362,84 @@ class WindowedStream[T, K, W <: Window](javaStream:
JavaWStream[T, K, W]) {
/**
* Applies an aggregation that that gives the maximum element of the
window by
- * the given position. When equality, returns the first.
+ * the given position. When equality, returns the first by default.
*/
def maxBy(position: Int): DataStream[T] =
aggregate(AggregationType.MAXBY,
- position)
+ position, true)
/**
* Applies an aggregation that that gives the maximum element of the
window by
- * the given field. When equality, returns the first.
+ * the given position. When equality, returns either the first or last
one depending
+ * on the parameter setting.
+ */
+ def maxBy(position: Int, first: Boolean): DataStream[T] =
aggregate(AggregationType.MAXBY,
+ position, first)
+
+ /**
+ * Applies an aggregation that that gives the maximum element of the
window by
+ * the given field. When equality, returns the first by default.
*/
def maxBy(field: String): DataStream[T] =
aggregate(AggregationType.MAXBY,
- field)
+ field, true)
+
+ /**
+ * Applies an aggregation that that gives the maximum element of the
window by
+ * the given field. When equality, returns either the first or last one
depending
+ * on the parameter setting.
+ */
+ def maxBy(field: String, first: Boolean): DataStream[T] =
aggregate(AggregationType.MAXBY,
+ field, first)
/**
* Applies an aggregation that that gives the minimum element of the
window by
- * the given position. When equality, returns the first.
+ * the given position. When equality, returns the first by default.
*/
def minBy(position: Int): DataStream[T] =
aggregate(AggregationType.MINBY,
- position)
+ position, true)
/**
* Applies an aggregation that that gives the minimum element of the
window by
- * the given field. When equality, returns the first.
+ * the given position. When equality, returns either the first or last
one depending
+ * on the parameter setting.
+ */
+ def minBy(position: Int, first: Boolean): DataStream[T] =
aggregate(AggregationType.MINBY,
+ position, first)
+
+ /**
+ * Applies an aggregation that that gives the minimum element of the
window by
+ * the given field. When equality, returns the first by default.
*/
def minBy(field: String): DataStream[T] =
aggregate(AggregationType.MINBY,
- field)
+ field, true)
+
+ /**
+ * Applies an aggregation that that gives the minimum element of the
window by
+ * the given field. When equality, returns either the first or last one
depending
+ * on the parameter setting.
+ */
+ def minBy(field: String, first: Boolean): DataStream[T] =
aggregate(AggregationType.MINBY,
+ field, first)
+
+ private def aggregate(aggregationType: AggregationType, position: Int):
DataStream[T] = {
+ aggregate(aggregationType, position, false)
+ }
private def aggregate(aggregationType: AggregationType, field: String):
DataStream[T] = {
+ aggregate(aggregationType, field, false)
+ }
+
+ private def aggregate(
+ aggregationType: AggregationType,
+ field: String,
+ first: Boolean): DataStream[T] = {
val position = fieldNames2Indices(getInputType(), Array(field))(0)
aggregate(aggregationType, position)
}
- def aggregate(aggregationType: AggregationType, position: Int):
DataStream[T] = {
+ private def aggregate(
+ aggregationType: AggregationType,
+ position: Int,
+ first: Boolean): DataStream[T] = {
--- End diff --
`first` is not used.
> Cannot get last element with maxBy/minBy
> ----------------------------------------
>
> Key: FLINK-2184
> URL: https://issues.apache.org/jira/browse/FLINK-2184
> Project: Flink
> Issue Type: Improvement
> Components: Scala API, Streaming
> Reporter: Gábor Hermann
> Priority: Minor
>
> In the streaming Scala API there is no method
> {{maxBy(int positionToMaxBy, boolean first)}}
> nor
> {{minBy(int positionToMinBy, boolean first)}}
> like in the Java API, where _first_ set to {{true}} indicates that the latest
> found element will return.
> These methods should be added to the Scala API too, in order to be consistent.
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