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From Jack Huang <jackhu...@mz.com>
Subject Re: Parsing source JSON String as Scala Case Class
Date Fri, 05 Aug 2016 17:42:44 GMT
Thanks Stephan. "lazy val" does the trick.

On Thu, Aug 4, 2016 at 2:33 AM, Stephan Ewen <sewen@apache.org> wrote:

> If the class has non-serializable members, you need to initialize them
> "lazily" when the objects are already in the distributed execution (after
> serializing / distributing them).
>
> Making a Scala 'val' a 'lazy val' often does the trick (at minimal
> performance cost).
>
> On Thu, Aug 4, 2016 at 3:56 AM, Jack Huang <jackhuang@mz.com> wrote:
>
>> Hi all,
>>
>> I want to read a source of JSON String as Scala Case Class. I don't want
>> to have to write a serde for every case class I have. The idea is:
>>
>> val events = env.addSource(new FlinkKafkaConsumer09[Event]("events", new JsonSerde(classOf[Event]),
kafkaProp))
>>
>> ​
>>
>> I was implementing my own JsonSerde with Jackson/Gson, but in both case I
>> get the error
>>
>> Task not serializable
>>     org.apache.flink.api.scala.ClosureCleaner$.ensureSerializable(ClosureCleaner.scala:172)
>>     org.apache.flink.api.scala.ClosureCleaner$.clean(ClosureCleaner.scala:164)
>>     org.apache.flink.streaming.api.scala.StreamExecutionEnvironment.scalaClean(StreamExecutionEnvironment.scala:568)
>>     org.apache.flink.streaming.api.scala.StreamExecutionEnvironment.addSource(StreamExecutionEnvironment.scala:498)
>>     com.fractionalmedia.stream.PricerEvent$.main(PricerEvent.scala:100)
>>
>> ​
>> It seems that both Jackson and Gson have classes that is not serializable.
>>
>> I couldn't find any other solution to perform this JSON-to-Case-Class
>> parsing, yet it seems a very basic need. What am I missing?
>>
>>
>> Thanks,
>> Jack
>>
>>
>>
>>
>

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