Scala, Logback Multiply Level Filter

MultipleLevelFilter.scala

class MultipleLevelFilter extends AbstractMatcherFilter[ILoggingEvent] {

  private var levels: Set[Level] = _

  def setLevels(levels: String): Unit = {
    this.levels = levels.split('|').map(Level.toLevel(_, Level.OFF)).toSet
  }

  def getLevels = levels

  override def decide(event: ILoggingEvent) = {
    if (levels.contains(event.getLevel)) onMatch
    else onMismatch
  }

  override def start(): Unit = if (this.levels != null && levels.nonEmpty) super.start()
}


<filter class="logger.MultipleLevelFilter">
  <levels>TRACE|DEBUG</levels>
  <onMatch>ACCEPT</onMatch>
  <onMismatch>DENY</onMismatch>
</filter>