How to convert from from java.util.Map to a Scala Map

Question

A Java API returns a java.util.Map;. I would like to put that into a Map[String,Boolean]

So imagine w

Answer 1

At least with Scala 2.9.2 there's an easier way with the collections conversions: import "import collection.JavaConversions._" and use "toMap".

Example:

// show with Java Map:

scala> import java.util.{Map=>JMap}
scala> val jenv: JMap[String,String] = System.getenv()
jenv: java.util.Map[String,String] = {TERM=xterm, ANT_OPTS=-Xmx512m ...}

scala> jenv.keySet()
res1: java.util.Set[String] = [TERM, ANT_OPTS...]

// Now with Scala Map:

scala> import collection.JavaConversions._
scala> val env: Map[String,String] = System.getenv.toMap // <--- TADA <---
env: Map[String,String] = Map(ANT_OPTS -> -Xmx512m, TERM -> xterm ...)

// Just to prove it's got Scala functionality:

scala> env.filterKeys(_.indexOf("TERM")>=0)
res6: scala.collection.immutable.Map[String,String] = Map(TERM -> xterm, 
  TERM_PROGRAM -> iTerm.app, ITERM_PROFILE -> Default)

It works fine with a java.util.map of String to Boolean.