interceptor.java

@Component
class UpdateTotalPriceInterceptor extends EmptyInterceptor
{
    @Override
    public void preFlush(Iterator entities)
    {
        while (entities.hasNext()) {
            updatePriceIfOrder(entities.next());
        }

        super.preFlush(entities);
    }

    private void updatePriceIfOrder(Object entity)
    {
        if (entity instanceof Order) {
            ((Order) entity).updateTotalPrice();
        }
    }
}