protected void addToMaintenanceQueue(NodePortTuple npt){
  if (maintenanceQueue.contains(npt) == false) {
    maintenanceQueue.add(npt);
  }
}

protected void addToMaintenanceQueue ( NodePortTuple npt ) { if ( maintenanceQueue . contains ( npt ) == false ) { maintenanceQueue . add ( npt ) ; } }
add a switch port to maintenance queue .
