CODEWITHSUNDEEP
javascala
Fobi
Fobi

Reputation: 445

How to convert Scala collection Seq[(Int, Seq[String])] to Java collection List[(int, List[String])]?

I know that there are two extremely useful objects in scala.collection package, which will help us to achieve this goal:

but I have some troubles to apply them in my case because my data structure is a little bit more complex than the other ones that I saw in many examples.

I'm in scala code and I want that my scala function return a Java collection. So I wanto to convert Scala Seq[(Int, Seq[String])] to Java collection List[(int, List[String])].

How can I do this?

Upvotes: 3

Views: 1295

Answers (2)

T. Gawęda
T. Gawęda

Reputation: 16076

Use map to at first map Seq[(Int, Seq[String])] to Seq[(Int, List[String])] and then use again the same function to main collection

import scala.collection.JavaConversions
val seq : Seq[(Int, Seq[String])] = some code
val seqOfLists = seq.map(s => (s._1, JavaConversions.seqAsJavaList(s._2)))
val listOfLists = JavaConversions.seqAsJavaList(seqOfLists)

Or newer API:

import scala.collection.JavaConverters._
val seq : Seq[(Int, Seq[String])] = some code
val seqOfLists = seq.map(s => (s._1, s._2.asJava))
val listOfLists = seqOfLists.asJava

Upvotes: 7

Jeffrey Chung
Jeffrey Chung

Reputation: 19517

JavaConversions is deprecated since Scala 2.12.0. Use JavaConverters instead:

import scala.collection.JavaConverters._

val seq: Seq[(Int, Seq[String])] = ???
val javaList = seq.map(x => (x._1, x._2.asJava)).asJava
// java.util.List[(Int, java.util.List[String])]

Upvotes: 3

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