Hi Laurent! On 31.03.20 10:43, Laurent Exsteens wrote:
Yesterday I managed to find another solution: create the type information outside of the class and pass it to the constructor. I can retrieve the type information from DataStream.getType() (whiich. This works well, and is acceptable in my case.
This is a valid solution which is also used internally in some parts of Flink.
I'm starting to understand that the problem resides in Java Generics type erasure: we cannot create the TypeInformation using a TypeHint inside the Generic class, since creating the TypeHint is a runtime operation which cannot access the generic type anymore, since it has been erased at compile time. Is my understanding correct?
Yes, this seems correct.
I'm still interested by a solution where everything could be done inside the flatMap function, and without extra wrap and unwrap (although I'm starting to think that is not possible due to type erasure).
It would be possible if you write your completely custom TypeSerializer, but that is probably a lot more effort than it would be worth, considering you also found the alternative solution.
Best, Aljoscha
