traits.scala

abstract class Metric {
  def parse(line:String):List[String]
}

class MetricData extends Metric {
  def parse(line:String):List[String] = {
    println("MetricData")
    List()
  }
}

trait MetricParser extends Metric {  }

trait DataTransferredMetric extends MetricParser {
  abstract override def parse(line:String):List[String] = {
    println("DataTransferredMetric")
    return super.parse(line) ++ List("DataTransferred")
  }
}

trait RequestsMetric extends MetricParser {
  abstract override def parse(line:String):List[String] = {
    println("RequestsMetric")
    return super.parse(line) ++ List("RequestsMetric")
  }
}

trait BytesInMetric extends MetricParser {
  abstract override def parse(line:String):List[String] = {
    println("BytesIn")
    return super.parse(line) ++ List("BytesIn")
  }
}

object MetricTest extends App {
  val parser = new MetricData with DataTransferredMetric with RequestsMetric
  val parser2 = new MetricData with DataTransferredMetric with BytesInMetric
  println(parser.parse(""))
  println("-------------------------------")
  println(parser2.parse(""))
  println("-------------------------------")
  println(parser.parse("HELLO"))
}