OrderService Class

OrderService.java

@Service
public class OrderService {

    //... 

    @Transactional
    public PurchaseOrder updateOrderLineStatus(long orderId, long orderLineId, OrderLineStatus newStatus) {
        PurchaseOrder po = repository.findById(orderId)
                .orElseThrow(() -> new EntityNotFoundException("order with id " + orderId + " doesn't exist!"));
        OrderLineStatus oldStatus = po.updateOrderLine(orderLineId, newStatus);
        eventBus.publishEvent(OrderLineUpdatedEvent.of(orderId, orderLineId, newStatus, oldStatus));
        repository.save(po);
        return po;
    }

    //...

}