FleetUI.java

public class FleetUI {

    private final String licensePlateRegex = "[0-9]{2}[\\s-]{0,1}[0-9]{2}[\\s-]{0,1}[A-IK-PR-VZ]{2}|[0-9]{2}[\\s-]{0,1}[A-IK-PR-VZ]{2}[\\s-]{0,1}[0-9]{2}|[A-IK-PR-WYZ]{2}[\\s-]{0,1}[0-9]{2}[\\s-]{0,1}[A-IK-PR-WYZ]{2}";

    final IFleet fleet;
    final Scanner scr;


    public FleetUI(IFleet fleet) {
        this.fleet = fleet;
        scr = new Scanner(System.in);
    }

    private void addVehicle() {
        String licencePlate = askForLicensePlate();

        if(licencePlate == null) {
            return;
        }

        if (fleet.contains(licencePlate)) {
            System.out.println("Vehicle already exists");
            return;
        }

        int year = PAInput.readInt("Year: ");
        int type = PAInput.chooseOption("What type of Vehicle is this",
                "Passenger Car", "Bus", "Cargo",
                "Quit");

        Vehicle vehicle = switch (type) {
            case 1: {
                int numberPassengers = PAInput.readInt("Number Passengers: ");
                yield new PassengerCar(licencePlate, year, numberPassengers);
            }
            case 2: {
                int numberPassengers = PAInput.readInt("Number Passengers: ");
                int loadCapacity = PAInput.readInt("Load capacity: ");
                yield new Bus(licencePlate, year, numberPassengers, loadCapacity);
            }
            case 3: {
                int loadCapacity = PAInput.readInt("Load capacity: ");
                yield new Cargo(licencePlate, year, loadCapacity);
            }
            default: {
                yield null;
            }
        };

        if(vehicle != null) {
            fleet.addVehicle(vehicle);
        }
    }

    private void removeVehicle() {
        String licencePlate = askForLicensePlate();

        if(licencePlate == null) {
            return;
        }

        if(fleet.removeVehicle(licencePlate)) {
            System.out.println("Vehicle removed");
        } else  {
            System.out.println("Vehicle not found");
        }
    }

    String askForLicensePlate() {
        String licencePlate;
        do {
            licencePlate = PAInput.readString("License Plate (xx-xx-xx) | Q to exit: ", false);
            if (licencePlate.equalsIgnoreCase("Q")) {
                return null;
            }
        } while (!Pattern.matches(licensePlateRegex, licencePlate.toUpperCase(Locale.ROOT)));

        return licencePlate;
    }

    public void go() {
        while (true) {
            switch (PAInput.chooseOption("Fleet Manager - " + fleet.getName(),
                    "Add new vehicle", "remove vehicle", "list all vehicles", "list all passenger vehicles", "list all load vehicles",
                    "Quit")) {
                case 1:
                    addVehicle();
                    break;
                case 2:
                    removeVehicle();
                    break;
                case 3:
                    System.out.println(fleet);
                    break;
                case 4:
                    System.out.println(fleet.toStringSortByNumberOfPassengers());
                    break;
                case 5:
                    System.out.println(fleet.toStringSortByMaxLoad());
                    break;
                case 6:
                    return;
            }
        }
    }
}