Scala - initializing mutable Maps and exposing them as immutable

Question

Is there any \"good\" code pattern for a Class initializing and populating private mutable Maps, and then exposing them as immutable ones? Or should I just eter

Answer 1

Something like:

scala> class X {
     |   private val mb = collection.immutable.Map.newBuilder[String, Int]
     |   def m = mb.result
     |   mb += ("a" -> 1)  // stuff
     | }
defined class X

scala> new X().m
res0: scala.collection.immutable.Map[String,Int] = Map(a -> 1)