Problems with scala

myreducer.scala

class MyReducer extends Reducer[Text, Text, Text, Text] {
  // How does one define a class level variable in Scala? Below does not work ...
  var mo: MultipleOutputs[Context] 


  def setup(context : Context) {
    mo = new MultipleOutputs(context)
  }

  def reduce(key : Text, values : java.util.Iterator[Text], context : Context) {
    for(log <- values) {
      mo.write(key, new Text(log), "/tmp/file-" + key)
    }
  }

  def cleanup(context : Context) {
    mo.close()
  }
}