@Override
  public List<Flight> getAllFlight() {
    List<Flight> flights = flightDao.getAllFlight();

    if (LOG.isInfoEnabled()) {
      LOG.info("get all flight. Flights : " + flights);
    }

    return flights;
  }
  @Override
  public String getFlightState(String flightNumber) {
    String flightState = flightDao.getFlightState(flightNumber);

    if (LOG.isInfoEnabled()) {
      LOG.info(
          "get flight state. Flight number : " + flightNumber + ". Flight state : " + flightState);
    }

    return flightState;
  }