A thread-safe version of scala.util.parsing.json.JSON

JSON.scala

// A thread-safe version of scala.util.parsing.json.JSON, as suggested
// by Matthew Neeley in response to a question on the Bay Area Scala
// Enthusiasts mailing list. Covered by the standard Scala license.

import scala.util.parsing.json.{ Parser => JSONParser, JSONObject, JSONArray }

class JSON extends JSONParser {
  private def resolveType(input: Any): Any = input match {
    case JSONObject(map) => map.transform { case (k,v) => resolveType(v) }
    case JSONArray(seq) => seq.map(resolveType)
    case other => other
  }
  def parse(input: String): Option[Any] = {
    phrase(root)(new lexical.Scanner(input)) match {
      case Success(result, _) => Some(resolveType(result))
      case _ => None
    }
  }
}

object JSON {
  // Could instead cache one parser per thread in a thread local variable,
  // but that only gives about a 10% performance improvement.
  def parse(input: String): Any = (new JSON).parse(input)
}

object JSONExample {
  def main(args: Array[String]) {
    println(JSON.parse("""{"foo": 1, "bar": "hello"}"""))
  }     
}