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 limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!
