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Subject: Immutable data
From: Jack <jack-knilf@marmelandia.com>
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Date: Wed, 23 Sep 2015 14:29:03 +0300
To: user@flink.apache.org
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Hi,

I'm having trouble integrating existing Scala code with Flink, due to POJO-o=
nly requirement.=20

We're using AnyVal heavily for type safety, and immutable classes as a defau=
lt. For example, the following does not work:

object Test {
  class Id(val underlying: Int) extends AnyVal

  class X(var id: Id) {
    def this() { this(new Id(0)) }=20
  }

  class MySource extends SourceFunction[X] {
    def run(ctx: SourceFunction.SourceContext[X]) {
      ctx.collect(new X(new Id(1)))
    }
    def cancel() {}
  }

  def main(args: Array[String]) {
    val env =3D StreamExecutionContext.getExecutionContext
    env.addSource(new MySource).print
    env.execute("Test")
  }
}

Currently I'm thinking that I would need to have duplicate classes and code f=
or Flint and for non-Flint code, or somehow use immutable interfaces for non=
-Flint code. Both ways are expensive in terms of development time.=20

Would you have any guidance on how to integrate Flink with a code base that h=
as immutability as a norm?

Thanks=