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From Martin Neumann <mneum...@sics.se>
Subject Re: TypeVariable problems
Date Mon, 02 May 2016 09:29:01 GMT
Hi Aljosha

Thanks for your answer!
I tried using returns but it does not work since the only place where I
could call it is within the function that has all the generic types so
there is no useful type hint to give. I could make the user hand over the
class definition for the type as well but that would complicate the
interface and I like to avoid that. Is there documentation or example
somewhere so I can see how to use

if you have time you can also reach me on hangout (might be faster than
email). :-)

cheers Martin

On Mon, May 2, 2016 at 11:23 AM, Aljoscha Krettek <aljoscha@apache.org>

> Hi,
> for user functions that have generics, such as you have, you have to
> manually specify the types somehow. This can either be done using
> InputTypeConfigurable/OutputTypeConfigurable or maybe using
> stream.returns(<type>).
> Cheers,
> Aljoscha
> On Fri, 29 Apr 2016 at 12:25 Martin Neumann <mneumann@sics.se> wrote:
>> Hej,
>> I have a construct of different generic classes stacked on each other to
>> create a library (so the type variables get handed on). And I have some
>> trouble getting it to work.
>> The current offender is a Class with 3 type variables <K, V, RV>
>> internally it calls:
>> .fold(new Tuple3<>(keyInit ,new Tuple2<Double,Double>(0d,0d), valueFold.getInit()),
new CountSumFold<V,K,RV>(keySelector,valueSelector,valueFold))
>> I initiated the class with <String, Tuple2<String,Double>,NullValue>
>> when I try to run it it I get the exception:
>> org.apache.flink.api.common.functions.InvalidTypesException: Type of
>> TypeVariable 'K' in 'class se.sics.anomaly.bs.models.CountSumFold' could
>> not be determined.
>> Anyone has an idea on how to fix this problem?
>> cheers Martin

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