Hello Thomas, On Monday, April 23, 2012 11:49:54 AM UTC+2, Thomas Broyer wrote: > > In RequestFactory's design, onFailure is really an exception, and should > never happen: errors should be conveyed as special return values. That > doesn't quite change your issue here, as the proxy wouldn't be reusable > either: that's because, again, RF has been designed with the idea that > things shouldn't go wrong. For instance, unique constraint violations are > not natural for (most / non-technical) users. Moreover, those kind of > conditions should probably be detected as ConstraintVIolations so the user > can "fix the proxy" and "resubmit his request". >
Could you help me a bit more by pointing to an example of what do you mean by "detected as ConstraintViolation"? I have a situation where the user must attribute a reference value to an entity, and this value must be unique. I can only know if it's unique after my service is called and either I attempt an insert and treat the exception, or if I make a previous select before the insert (very low risk of concurrence issues for my case, I think I could safely ignore such risk). In either case, the request is already gone and the service has already been called. From what I understood by reading the previous thread I linked to, it is already too late to reuse the proxy. By the way, I was not using onFailure as you say it should be used. I was using it for general business failures. We've even implemented a generic Receiver to deal with that. Not challenging what you say, but it really doesn't look like RF was built with the idea that errors should be treated in the return value... the return value most of the time is a proxy (or Collection of proxies) to an entity used in the back-end. Entities are not supposed to have request-specific error data. Basically, to operate like that, I would need different DTOs for every request, and proxy these DTOs, which would contain the needed entities plus error information. Is that how RF is supposed to be used? Thank you, Tiago. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/tsM6lHU0uvQJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
