quarkus-patterns

Quarkus Development Patterns

Quarkus 3.x architecture and API patterns for cloud-native, event-driven services with Apache Camel.

When to Activate

• Building REST APIs with JAX-RS or RESTEasy Reactive
• Structuring resource → service → repository layers
• Implementing event-driven patterns with Apache Camel and RabbitMQ
• Configuring Hibernate Panache, caching, or reactive streams
• Adding validation, exception mapping, or pagination
• Setting up profiles for dev/staging/production environments (YAML config)
• Custom logging with LogContext and Logback/Logstash encoder
• Working with CompletableFuture for async operations
• Implementing conditional flow processing
• Working with GraalVM native compilation

Service Layer with Multiple Dependencies

@Slf4j
@ApplicationScoped
@RequiredArgsConstructor
public class OrderProcessingService {

    private final OrderValidator orderValidator;
    private final EventService eventService;
    private final OrderRepository orderRepository;
    private final FulfillmentPublisher fulfillmentPublisher;
    private final AuditPublisher auditPublisher;

    @Transactional
    public OrderReceipt process(CreateOrderCommand command) {
        ValidationResult validation = orderValidator.validate(command);
        if (!validation.valid()) {
            eventService.createErrorEvent(command, "ORDER_REJECTED", validation.message());
            throw new WebApplicationException(validation.message(), Response.Status.BAD_REQUEST);
        }

        Order order = Order.from(command);
        orderRepository.persist(order);

        OrderReceipt receipt = OrderReceipt.from(order);
        fulfillmentPublisher.publishAsync(receipt);
        auditPublisher.publish("ORDER_ACCEPTED", receipt);
        eventService.createSuccessEvent(receipt, "ORDER_ACCEPTED");

        log.info("Processed order {}", order.id);
        return receipt;
    }
}

Key Patterns:

• @RequiredArgsConstructor for constructor injection via Lombok
• @Slf4j for Logback logging
• @Transactional on service methods that write through Panache or repositories
• Validate input before persistence or message publication
• Event tracking for success/error scenarios
• Async Camel message publishing