Hi,

The issue is that this problem appears when I want to create a stream source.

StreamExecutionEnvironment.addSource(new MySourceFunction())
…
Where the stream source class is

MySourceFunction<TupleEvent2> implements SourceFunction<TupleEvent2>
{
…
}

In such a case I am not sure how I can pass the outertype  nor how I can pass 
it using the “.returns()” method as Timo suggested



Dr. Radu Tudoran
Research Engineer - Big Data Expert
IT R&D Division

[cid:image007.jpg@01CD52EB.AD060EE0]
HUAWEI TECHNOLOGIES Duesseldorf GmbH
European Research Center
Riesstrasse 25, 80992 München

E-mail: radu.tudo...@huawei.com
Mobile: +49 15209084330
Telephone: +49 891588344173

HUAWEI TECHNOLOGIES Duesseldorf GmbH
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www.huawei.com<http://www.huawei.com/>
Registered Office: Düsseldorf, Register Court Düsseldorf, HRB 56063,
Managing Director: Bo PENG, Wanzhou MENG, Lifang CHEN
Sitz der Gesellschaft: Düsseldorf, Amtsgericht Düsseldorf, HRB 56063,
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From: Wang Yangjun [mailto:yangjun.w...@aalto.fi]
Sent: Tuesday, March 08, 2016 7:15 PM
To: user@flink.apache.org
Subject: Re: ype of TypeVariable could not be determined

Hi Radu,

I met this issue also. The reason is outTypeInfo couldn't be created base on 
generic type when a transform applied.

public <R> SingleOutputStreamOperator<R, ?> transform(String operatorName, 
TypeInformation<R> outTypeInfo, OneInputStreamOperator<T, R> operator)
The solution would be passed Calss<T> to your UDF and create TypeInfomation<R> 
by yourself.

Best,
Jun

From: Radu Tudoran <radu.tudo...@huawei.com<mailto:radu.tudo...@huawei.com>>
Reply-To: "user@flink.apache.org<mailto:user@flink.apache.org>" 
<user@flink.apache.org<mailto:user@flink.apache.org>>
Date: Tuesday 8 March 2016 at 19:57
To: "user@flink.apache.org<mailto:user@flink.apache.org>" 
<user@flink.apache.org<mailto:user@flink.apache.org>>
Subject: ype of TypeVariable could not be determined

Hi,

I am trying to create a custom stream source. I first build this with generic 
and I run into problems regarding type extraction. I tried to put concrete 
types but run into the same issue (see errors below). Can anyone provide a 
solution to solve this issue.

Caused by: org.apache.flink.api.common.functions.InvalidTypesException: Type of 
TypeVariable 'IN' in 'class test.MySourceFunction' could not be determined. 
This is most likely a type erasure problem. The type extraction currently 
supports types with generic variables only in cases where all variables in the 
return type can be deduced from the input type(s).
       at 
org.apache.flink.api.java.typeutils.TypeExtractor.createTypeInfoWithTypeHierarchy(TypeExtractor.java:498)
       at 
org.apache.flink.api.java.typeutils.TypeExtractor.privateCreateTypeInfo(TypeExtractor.java:380)
       at 
org.apache.flink.api.java.typeutils.TypeExtractor.createTypeInfo(TypeExtractor.java:346)
       at 
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1152)
       at 
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1107)
       at 
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1089)
       ... 1 more


Caused by: org.apache.flink.api.common.functions.InvalidTypesException: Type of 
TypeVariable 'TupleEvent2' in 'class test.MySourceFunctionTuple' could not be 
determined. This is most likely a type erasure problem. The type extraction 
currently supports types with generic variables only in cases where all 
variables in the return type can be deduced from the input type(s).
       at 
org.apache.flink.api.java.typeutils.TypeExtractor.createTypeInfoWithTypeHierarchy(TypeExtractor.java:498)
       at 
org.apache.flink.api.java.typeutils.TypeExtractor.privateCreateTypeInfo(TypeExtractor.java:380)
       at 
org.apache.flink.api.java.typeutils.TypeExtractor.createTypeInfo(TypeExtractor.java:346)
       at 
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1152)
       at 
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1107)
       at 
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.java:1089)
       ... 1 more


Dr. Radu Tudoran
Research Engineer - Big Data Expert
IT R&D Division

[cid:image007.jpg@01CD52EB.AD060EE0]
HUAWEI TECHNOLOGIES Duesseldorf GmbH
European Research Center
Riesstrasse 25, 80992 München

E-mail: radu.tudo...@huawei.com<mailto:radu.tudo...@huawei.com>
Mobile: +49 15209084330
Telephone: +49 891588344173

HUAWEI TECHNOLOGIES Duesseldorf GmbH
Hansaallee 205, 40549 Düsseldorf, Germany, 
www.huawei.com<http://www.huawei.com/>
Registered Office: Düsseldorf, Register Court Düsseldorf, HRB 56063,
Managing Director: Bo PENG, Wanzhou MENG, Lifang CHEN
Sitz der Gesellschaft: Düsseldorf, Amtsgericht Düsseldorf, HRB 56063,
Geschäftsführer: Bo PENG, Wanzhou MENG, Lifang CHEN
This e-mail and its attachments contain confidential information from HUAWEI, 
which is intended only for the person or entity whose address is listed above. 
Any use of the information contained herein in any way (including, but not 
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persons other than the intended recipient(s) is prohibited. If you receive this 
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