CODEWITHSUNDEEP
javascalaapache-spark
Georg Heiler
Georg Heiler

Reputation: 17724

Convert java to scala code

Converting java to scala code I face a strange Problem An example can be found here https://gist.github.com/geoHeil/895260a04d3673b9848b345edf388a2d The error is 

[error] src/main/scala/myOrg/CustomInputMapperWKT.scala:17: overriding method call in trait FlatMapFunction of type (x$1: String)java.util.Iterator[Any];
[error]  method call has incompatible type
[error]   override def call(line: String): Iterator[_] = {

When trying to convert spark java to spark scala API I am struggling to port this java class https://github.com/DataSystemsLab/GeoSpark/blob/master/src/main/java/org/datasyslab/geospark/showcase/UserSuppliedPolygonMapper.java#L59-L81 to scala.

Where

class CustomInputMapperWKT extends FlatMapFunction[String, Any] {
....
override def call(line: String): Iterator[_] = {
val result: collection.Seq[Polygon] with Growable[Polygon] = mutable.Buffer[Polygon]()
result.iterator
  }
}

is the minimal sample describing the problem.

edit

Trying to fix a possible typing problem I substituted Any with its respective type of polygon. But that doesn't help to Fox the problem.

Upvotes: 1

Views: 2321

Answers (1)

Alex Karpov
Alex Karpov

Reputation: 564

Have you tried this signature?

override def call(t: String): java.util.Iterator[Any] = {
...

Because this code example is compiled successfully:

import org.apache.spark.api.java.function.FlatMapFunction
import collection.JavaConverters._

class CustomInputMapperWKT extends FlatMapFunction[String, Any] {
  override def call(t: String): java.util.Iterator[Any] = {
    ...
    result.iterator.asJava
  }
}

Upvotes: 2

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