FurkanBerkant/comodif-challenge

comodif coding challenge

As part of our interview process, we expect you to complete a coding challenge in order for us to understand your coding skills. The challenge is a Java11 + Spring Boot project which uses H2 as the database.

Question 1: Basic Flight Booking System

For flight booking system the necessary REST services are listed below. We kindly ask you to implement them.

Requirements

• Implementation of a flight booking system REST endpoints

  • Note : Entity fields and relations between them is up to you. (Flight, Seat , Payment and all other possible database entities..)
    • Flight endpoint -> listing, adding, removing and updating
    • Seat for existing flight -> listing, adding, removing or updating services.
    • Flight/Seat listing service which returns flight name, description, available seats, prices and so on.
    • Using of business exceptions with REST endpoints implementations
    • Prepare a Postman collection to test written REST endpoints

• Payment service for the end user to buy their selected seat.

• A seat should not be sold to two passengers.

• If there are 2 passengers pay at the same time for the same seat, first successful should buy the seat and the 2nd one should fail with an appropriate message. We expect IT test for this case.

• No front end is necessary.

Question 2 : Latency Management

PaymentService.java class calling bank endpoints. The bank responses are persisted to database.In PaymentServiceTest.java class we have simulated 100 customers calling the payment service at the same time.

    public void pay(BigDecimal price) {
        //pay with bank
        BankPaymentRequest request = new BankPaymentRequest();
        request.setPrice(price);
        BankPaymentResponse response = bankService.pay(request);

        //insert records
        Payment payment = new Payment();
        payment.setBankResponse(response.getResultCode());
        payment.setPrice(price);
        paymentRepository.save(payment);
        logger.info("Payment saved successfully!");
    }

In the simulation for some reason the bank response times take ~5 seconds. Due to this latency, a database connection problem is encountered after some time. (Running the PaymentServiceTest.java class displays "Connection is not available, request timed out after 20005ms." error after some time.)

Find a way to persist bank responses to the database in this situation.

Requirements

• DB connection pool must stay the same .
• DatabaseConfiguration.java, BankService.java, PaymentServiceClients.java and PaymentServiceTest.java classes must not be changed.
• In case of an error, there must not be any inconsistent data in the database.