public void setAlphaRoad(int pos) throws InfraException { if (pos > 3 || pos < 0) throw new InfraException("Position out of range"); if (allRoads[pos] == null) throw new InfraException("No road is conencted at position " + pos); alphaRoads = (Road[]) Arrayutils.addElementUnique(alphaRoads, allRoads[pos]); updateLanes(); }