Pull Request #7231
Add idempotent payment retry handling
Prevents duplicate charges on merchant retries by checking an idempotency key before processing each payment. Returns a cached result for duplicate requests.
Ready to merge
service/PaymentService.java+44 additions
Viewed1
@Service
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public class PaymentService {
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@Autowired private IdempotencyRepository idempotencyRepo;
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@Autowired private PaymentGateway gateway;
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@Autowired private PaymentRepository paymentRepo;
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+ public PaymentResult processPayment(
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+ PaymentRequest request, String idempotencyKey) {
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+
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+ // Return cached result if we've seen this key
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+ Optional<IdempotencyRecord> existing =
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+ idempotencyRepo.findByKey(idempotencyKey);
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+
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+ if (existing.isPresent()) {
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+ return existing.get().getCachedResult();
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+ }
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+
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+ // Process the payment
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+ Payment payment = new Payment(
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+ request.getAmount(),
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+ request.getCurrency(),
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+ request.getCustomerId()
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+ );
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+ PaymentResult result = gateway.charge(payment);
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+
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+ // Save the idempotency record
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+ IdempotencyRecord record = new IdempotencyRecord(
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+ idempotencyKey, result
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+ );
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+ idempotencyRepo.save(record);
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+
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+ return result;
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+ }
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+ }
SL
samir_lead
Approved review
The flow is correct — check key, return cached result, otherwise process and cache. Clean implementation of the idempotency pattern. LGTM.