Type-safe configuration in Scala

configuration.scala

trait Handler

class Handler1 extends Handler
class Handler2 extends Handler

trait HandlerConfiguration {
  val handler1: Handler
  val handler2: Handler
}

type Configured[A] = HandlerConfiguration => A

object MyConfiguration extends HandlerConfiguration {
  override val handler1 = new Handler1
  override val handler2 = new Handler2
}

class ClassThatNeedsAHandler(handler: Handler) {
  def f = handler.getClass.getName
}

val generator: Configured[ClassThatNeedsAHandler] = handlerConfig => new ClassThatNeedsAHandler(handlerConfig.handler1)

val myClass = generator(MyConfiguration)
myClass.f  /* should say "Handler1" */