How to use Clipboard in Scala

ClipboardTest.scala

import java.awt.datatransfer.FlavorListener
import java.awt.datatransfer.FlavorEvent
import java.awt.Toolkit
import java.awt.datatransfer.DataFlavor
import scala.annotation.tailrec

object ClipboardTest {
  private var listener: Option[StrFlavorListener] = None

  def clipboard = Toolkit.getDefaultToolkit.getSystemClipboard

  def startTest {
    listener match {
      case Some(_) =>
      case None =>
        val l = new StrFlavorListener
        listener = Option(l)
        clipboard.addFlavorListener(l)
        println(DataFlavor.imageFlavor.getRepresentationClass)
    }
  }

  def showListenerList {
    clipboard.getFlavorListeners foreach println
  }

  def stopTest {
    listener match {
      case Some(l) => clipboard.removeFlavorListener(l)
      case None    =>
    }
  }

  class StrFlavorListener extends FlavorListener {
    override def flavorsChanged(e: FlavorEvent) {
      println(e.toString)
      println(e.getSource)
    }
  }

  class ClipboardWatcher(flavor: DataFlavor) {
    private var watching = false

    def getData = flavor.getRepresentationClass.cast(clipboard.getData(flavor))

    def start(whenChanged: Any => Unit) {
      var data = Option(getData)
      @tailrec def loop {
        (data, Option(getData)) match {
          case (Some(d1), d @ Some(d2)) if d1 != d2 =>
            whenChanged(d2)
            data = d
          case (None, d @ Some(d1)) =>
            whenChanged(d1)
            data = d
          case _ =>
        }
        Thread.sleep(100)
        if (watching) { loop }
      }
      watching = true
      loop
      watching = false
    }

    def stop { watching = false }
  }
}