Payment

Payment.java

@Controller
public class PaymentController {

    public final UserService userService;
    public final PaymentService paymentService;
    
    public PaymentController(UserService userService, PaymentService paymentService) {
        this.userService = userService;
        this.paymentService = paymentService;
    }

    @GetMapping("users/{id}")
    public String showPage(ModelMap model, @PathVariable long id) {
        User user = userService.getUserById(id);
        
        model.addAttribute( new PaymentForm(user) );
        
        return "payment_view";
    }

    @PostMapping("createPayment")
    public String showPage(PaymentForm form, BindingResult result) {
        
        if ( ! result.hasErrors() ) {
            User user = userService.getUserById(form.getdUserId());
            paymentService.createPayment(user, form.getAmount(), form.getMethod());
        }
        
        return "payment_view";
    }

}


@Service
public class PaymentService {

    private final static int CREDIT_CARD    = 1;
    private final static int BANK_TRANSFER  = 2;
    
    private User user;
    private int amount;
    
    
    public void createPayment(User user, int amount, int method) {
        this.user = user;
        this.amount = amount;
        
        if(method == CREDIT_CARD){
            handleCreditCardPayment();
        } else {
            handleBankTranswerPayment();
        }
    }
    
    private void handleCreditCardPayment() {
        save( new Transaction(user, amount, CREDIT_CARD));
    }
    
    private void handleBankTranswerPayment() {
        save( new Transaction(user, amount, BANK_TRANSFER));
    }


    private void save(Transaction transaction) {}
    
}


public class PaymentForm {

    @Min(1)
    @Max(100)
    private int amount = 50;
    private int method;
    private long userId;

    public PaymentForm() {
    }

    public PaymentForm(User user) {
        this.userId = user.getId();
    }

    public int getAmount() {
        return amount;
    }

    public void setAmount(int amount) {
        this.amount = amount;
    }

    public long getdUserId() {
        return userId;
    }

    public void setUserId(long userId) {
        this.userId = userId;
    }

    public int getMethod() {
        return method;
    }

    public void setMethod(int method) {
        this.method = method;
    }

}