Convert Scala nested Map to Java nested util.Map

Question

I use Scala in my project and want to integrate with Stripe, but it provides only Java API. For example, to create session I use:

val params = new util.HashMap[String, AnyRef]
val paymentMethodTypes = new util.ArrayList[String]
paymentMethodTypes.add("card")
params.put("payment_method_types", paymentMethodTypes)
params.put("mode", "setup")
params.put("success_url", "https://test.app/success")
params.put("cancel_url", "https://test.app/cancel")
val session = Session.create(params)

This code works perfectly, but it's very ugly and contains a lot of boilerplate. I'd like to use a Scala Map[String, AnyRef] and create session as follows:

import scala.collection.JavaConverters._
val params2: Map[String, AnyRef] = Map(
  "payment_method_types" -> List("card"),
  "mode" -> "setup",
  "success_url" -> "https://test.app/success",
  "cancel_url" -> "https://test.app/cancel"
)
val session2 = Session.create(mapAsJavaMap[String, AnyRef](params2))

It turns out that mapAsJavaMap can't convert nested objects in the Map. Is there a way to convert arbitrary Scala Map with other Maps and Lists inside to their Java equivalents?

What version of scala? What error do you get?

smac89
– smac89

2019-09-20 02:46:10 +00:00
Commented Sep 20, 2019 at 2:46 — smac89
– smac89, Commented Sep 20, 2019 at 2:46

jwvh · Accepted Answer · 2019-09-20 10:34:49Z

3

JavaConverters has been deprecated. Try CollectionConverters.

import scala.jdk.CollectionConverters._

def convertMap[K](scalaMap :Map[K,AnyRef]) :java.util.Map[K,AnyRef] =
  scalaMap.map{ case (k,v) => v match {
    case m:Map[_,AnyRef] => (k, convertMap(m))  //recursive
    case l:List[_]       => (k, l.asJava)       //java.util.List[_]
    case _               => (k, v)              //unchanged
  }}.asJava

Not sure if this will actually work for you, what with all the values being type AnyRef. Try it and see what happens.

edited Sep 20, 2019 at 10:34

answered Sep 20, 2019 at 6:50

jwvh

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1 Comment

Bartłomiej Szałach Over a year ago

I get

non-variable type argument AnyRef in type pattern scala.collection.immutable.Map[_,AnyRef] (the underlying of Map[_,AnyRef]) is unchecked since it is eliminated by erasure

fenixil · Accepted Answer · 2019-09-20 02:23:44Z

2

You can use JavaConverters and here is an example how you can convert collections recursively.

answered Sep 20, 2019 at 2:23

fenixil

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