step-2-new-use-case.md

New use case creation

Kata goal

Implement a new use case that goes through all the hexagon

Business

We now want to have booking created automatically and stored so that the next time we started the application it gets the already created bookings.

Steps

Add a creation use case

Add a cron task that creates a new pallet booking in the C:\data\bookings.csv file

• Prepare the inside part
  • Start with the test by using a kind of in memory persistence and without using mockito
  • Do the implementation
  • Write down your questions and choices
  • What was difficult or easy?
• Do the adapters
  • Is it easy to identify adapters?

Code extracts

Here are some coding sample to faster your adapter creation

File appender method

    @Override
    public void create(PalletBooking palletBooking) {
        String bookingLine = palletBooking.getPartner() + "," + palletBooking.getQuantity() + System.getProperty("line.separator");
        try {
            Files.writeString(Path.of("c:\\data\\bookings.csv"), bookingLine, StandardOpenOption.APPEND);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

Spring scheduler

@Component
@EnableScheduling
public class BookingCreationScheduler {

    private final ForCreatingBooking forCreatingBooking;
    private final Random random = new Random();

    public BookingCreationScheduler() {
        ForHandlingBookings forGettingBooking = new FileBookingRepository();
        this.forCreatingBooking = new BookingManager(forGettingBooking);
    }

    //Every 15 seconds
    @Scheduled(fixedDelay = 15 * 1000)
    public void createBooking() {
        PalletBooking palletBooking = new PalletBooking("Cron partner", (long) random.nextInt(20));
        forCreatingBooking.create(palletBooking);
    }
}