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From Martin Gainty <mgai...@hotmail.com>
Subject RE: Understanding org.apache.kafka.streams.errors.TopologyBuilderException
Date Sat, 08 Oct 2016 13:59:06 GMT

> From: sjmittal@gmail.com
> Date: Sat, 8 Oct 2016 15:30:33 +0530
> Subject: Understanding org.apache.kafka.streams.errors.TopologyBuilderException
> To: users@kafka.apache.org
> Hi,
> I am getting this exception
> Exception in thread "main"
> org.apache.kafka.streams.errors.TopologyBuilderException: Invalid topology
> building: KTABLE-MAPVALUES-0000000007 and KSTREAM-AGGREGATE-0000000009 are
> not joinable
MG>look at join declaration for org.apache.kafka.streams.kstream.internals.KTableImpl.java
MG> public <V1, R> KTable<K, R> join(KTable<K, V1> other, ValueJoiner<V,
V1, R> joiner) 
MG>method join assumes 2 collections that exactly match the generic declaration of join

MG>KTable<String, Map<String, List<V1>>> !=  KTable<String, List<V1>>
(2nd parameter is missing both V and R declarators)
MG>you can establish a new collection of KTable<String, List<V1>>

MG>and then *join* KTable<String, Map<String, List<V1>>>  into  KTable<String,
List<V1>>  thru custom join method

> What I am trying to do is I aggregate a KStream into a KTable of type
> KTable<String, Map<String, List<V>>>
> and I am trying to join it to another KStream which is aggregated into
> another KTable of type
>  KTable<String, List<V>>
> Since keys of both the final KTable are same, I don't understand why it is
> giving this exception.
> Thanks
> Sachin
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