You are viewing a plain text version of this content. The canonical link for it is here.
Posted to jira@kafka.apache.org by "Matthias J. Sax (JIRA)" <ji...@apache.org> on 2018/11/21 00:58:00 UTC
[jira] [Updated] (KAFKA-7653) Streams-Scala: Add type level
differentiation for Key and Value serdes.
[ https://issues.apache.org/jira/browse/KAFKA-7653?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Matthias J. Sax updated KAFKA-7653:
-----------------------------------
Labels: scala (was: )
> Streams-Scala: Add type level differentiation for Key and Value serdes.
> -----------------------------------------------------------------------
>
> Key: KAFKA-7653
> URL: https://issues.apache.org/jira/browse/KAFKA-7653
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Mark Tranter
> Assignee: Mark Tranter
> Priority: Minor
> Labels: scala
>
> Implicit resolution/conversion of Serdes/Consumed etc is a big improvement for the Scala Streams API. However in cases where a user needs to differentiate between Key and Value serializer functionality (i.e. using the Schema Registry), implicit resolution doesn't help and could cause issues.
> e.g.
> {code:java}
> case class MouseClickEvent(pageId: Long, userId: String)
> builder
> // Long serde taken from implicit scope configured with
> // `isKey` = true
> .stream[Long, MouseClickEvent]("mouse-clicks")
> .selectKey((_,v) => v.userId)
> .groupByKey
> .aggregate(() => 0L, (_: String, mce: MouseClickEvent, count: Long) => count + 1)
> .toStream
> // Same Long serde taken from implicit scope configured with
> // `isKey` = true, even thought the `Long` value in this case
> // will be the Value
> .to("mouse-clicks-by-user")
> {code}
> It would be ideal if Key and Value Serde/SerdeWrapper types/type classes could be introduced to overcome this limitation.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)