docs: public boolean addBusLine(BusLine busLine) {
  		if (busLine == null) {
  			return false;
  		}
  		if (this.busLines.indexOf(busLine) != -1) {
  			return false;
  		}
  		if (!this.busLines.add(busLine)) {
  			return false;
  		}
  		final boolean isValidLine = busLine.isValidPrimitive();
  		busLine.setEventFirable(isEventFirable());
  		busLine.setContainer(this);
  		if (isEventFirable()) {
  			fireShapeChanged(new BusChangeEvent(this,
  					BusChangeEventType.LINE_ADDED,
  					busLine,
  					this.busLines.size() - 1,
  					"shape", //$NON-NLS-1$
  					null,
  					null));
  			if (!isValidLine) {
  				revalidate();
  			} else {
  				checkPrimitiveValidity();
  			}
  		}
  		return true;
  	}