Hi,
which version of Flink are you using, by the way? This would help me narrow
down on possible causes of the problem.
Cheers,
Aljoscha
> On 26 Feb 2016, at 10:34, Nirmalya Sengupta <sengupta.nirma...@gmail.com>
> wrote:
>
> Hello Aljoscha,
>
> I have also tried by using the field's name in the sum("field3") function
> (like you have suggested), but this time the exception is different:
>
> --------------------------------------------------------------------
>
> Exception in thread "main" java.lang.ExceptionInInitializerError
> at
> org.apache.flink.quickstart.StreamWindowExperiments.MultiWindowing.main(MultiWindowing.scala)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:497)
> at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
> Caused by: java.lang.IllegalArgumentException: Key expressions are only
> supported on POJO types and Tuples. A type is considered a POJO if all its
> fields are public, or have both getters and setters defined
> at
> org.apache.flink.streaming.util.FieldAccessor$PojoFieldAccessor.<init>(FieldAccessor.java:175)
> at
> org.apache.flink.streaming.util.FieldAccessor.create(FieldAccessor.java:92)
> at
> org.apache.flink.streaming.api.functions.aggregation.SumAggregator.<init>(SumAggregator.java:49)
> at
> org.apache.flink.streaming.api.datastream.WindowedStream.sum(WindowedStream.java:390)
> at
> org.apache.flink.quickstart.StreamWindowExperiments.MultiWindowing$.<init>(MultiWindowing.scala:63)
> at
> org.apache.flink.quickstart.StreamWindowExperiments.MultiWindowing$.<clinit>(MultiWindowing.scala)
> ... 6 more
>
> ---------------------------------------------------------------------
>
> I have used both of the styles of calling sum() in earlier, but I never got
> this exception. That's why I am a little confused. 'Reading' is a _case
> class_ and hence, a POJO as I understand. Yet, the message seems to say that
> it is not.
>
> -- Nirmalya
>
> --
> Software Technologist
> http://www.linkedin.com/in/nirmalyasengupta
> "If you have built castles in the air, your work need not be lost. That is
> where they should be.
> Now put the foundation under them."
