Hi there,
Yeah with 0.10.2 some Scala applications need to explicitly declare the type of
certain variables. See this:
http://docs.confluent.io/current/streams/upgrade-guide.html#scala
<http://docs.confluent.io/current/streams/upgrade-guide.html#scala>
Thanks
Eno
> On Jun 17, 2017, at 10:03 PM, Björn Häuser <bjoernhaeu...@gmail.com> wrote:
>
> Hi!
>
> I am maintaining an application which is written in Kafka and uses the
> kafka-streams library.
>
> As said in the topic, after trying to upgrade from 0.10.1.1 to 0.10.2.1, I am
> getting the following compilation error:
>
> [error] found : service.streams.transformers.FilterMainCoverSupplier
> [error] required: org.apache.kafka.streams.kstream.TransformerSupplier[_ >:
> String, _ >: ?0(in value x$1), org.apache.kafka.streams.KeyValue[?,?]]
> [error] Note: String <: Any (and
> service.streams.transformers.FilterMainCoverSupplier <:
> org.apache.kafka.streams.kstream.TransformerSupplier[String,dto.ContentDataDto,org.apache.kafka.streams.KeyValue[String,dto.ContentDataDto]]),
> but Java-defined trait TransformerSupplier is invariant in type K.
> [error] You may wish to investigate a wildcard type such as `_ <: Any`. (SLS
> 3.2.10)
> [error] Note: dto.ContentDataDto <: Any (and
> service.streams.transformers.FilterMainCoverSupplier <:
> org.apache.kafka.streams.kstream.TransformerSupplier[String,dto.ContentDataDto,org.apache.kafka.streams.KeyValue[String,dto.ContentDataDto]]),
> but Java-defined trait TransformerSupplier is invariant in type V.
> [error] You may wish to investigate a wildcard type such as `_ <: Any`. (SLS
> 3.2.10)
> [error] .transform(filterMainCover,
> FilterMainCoverSupplier.StateStoreName)
>
> The definition of the Transformer is as follows:
>
> class FilterMainCover extends Transformer[String, ContentDataDto,
> KeyValue[String, ContentDataDto]] {
> }
>
> The definition of the TransformerSupplier is as follows:
>
> class FilterMainCoverSupplier extends TransformerSupplier[String,
> ContentDataDto, KeyValue[String, ContentDataDto]] {
>
> override def get(): Transformer[String, ContentDataDto, KeyValue[String,
> ContentDataDto]] = new FilterMainCover()
>
> }
>
>
> I went through the confluent examples and could see that it is supposed to
> just work. Anyone got an Idea what I am doing wrong?
>
> Thanks
> Björn
>
