Re: Java 8 and type erasure

Posted by Aljoscha Krettek on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Java-8-and-type-erasure-tp2411p2419.html

Unfortunately, this also doesn't work for the same reasons. The generic types of generic parameters of a lambda are not stored anywhere. Stephan mentioned to me that the only possibility right now would be to look at the code using something like ASM to find a cast in the code to the concrete type of the generic parameter.

On Tue, 18 Aug 2015 at 11:35 Kristoffer Sjögren <[hidden email]> wrote:

How about https://github.com/jhalterman/typetools?

On Tue, Aug 18, 2015 at 11:16 AM, Aljoscha Krettek <[hidden email]> wrote:
> Hi Kristoffer,
> I'm afraid not, but maybe Timo has some further information. In this
> extended example we can see the problem:
> https://gist.github.com/aljoscha/84cc363d13cf1dfe9364. The output is:
>
> Type is: class org.apache.flink.examples.java8.wordcount.TypeTest$Thing
> class org.apache.flink.examples.java8.wordcount.TypeTest$Thing
> Type is: class org.apache.flink.examples.java8.wordcount.TypeTest$Thing
> class org.apache.flink.examples.java8.wordcount.TypeTest$Thing
> Type is :
> org.apache.flink.examples.java8.wordcount.TypeTest.org.apache.flink.examples.java8.wordcount.TypeTest$Thing<java.lang.String>
> class org.apache.flink.examples.java8.wordcount.TypeTest$Thing
>
> So with the two lambda calls it does not correctly determine the generic
> parameter of Thing while it works with the anonymous class.
>
> I was exited when I saw the example because we've been trying for so long to
> get this to work. Maybe we have to wait for java 19 to get this to work. ;-)
>
> Thanks a lot for helping, though. :D
> Aljoscha
>
> On Tue, 18 Aug 2015 at 11:01 Kristoffer Sjögren <[hidden email]> wrote:
>>
>> Hi
>>
>> Potential fix for writing flink jobs using lamdas without Eclipse JDT?
>>
>> https://gist.github.com/aslakhellesoy/3678beba60c109eacbe5
>>
>> Cheers,
>> -Kristoffer