For both of those cases, I'd use an exception. The UI layer can catch the first one and reprompt for the username. The second one should probably just bubble all the way up to the global onError handler, since the app is dead without the DB, at least for processing logins. By the time gets to the service layer, all your user validation should be complete. As such, if an error comes up that the service layer can't handle by itself (e.g. something besides a transaction deadlock), it's fatal to the service layer and bubbles out. Maybe the UI layer handles it (like invalid username exceptions), or maybe not (like database is dead), but the service layer needn't care.
cheers, barneyb On Mon, Oct 20, 2008 at 4:23 PM, Matthew <[EMAIL PROTECTED]> wrote: > > Hi everyone > > How are people managing messages in their OO code i.e. how do you pass > errors or comments from a component which is deep down in the business > layer - say perhaps from a DAO back up to the view. I've had a look at > various projects which I've downloaded and seen that some people use > CFTHROW type=application which means that this can be picked up at the > top level (but it seems odd to me because it is making the assumption > that some other object / code will pick it up i.e. it is not > explicitly saying "I had an error"). Some other projects built arrays > of messages and returned this. But how would you use such an array > solution if you were wanting to pass a bean as well as the array (I > guess you would have to return a structure with the array and bean > inside)?. > > Perhaps an example would help, so let's take a very common user-login > scenario > > 1. User enters email/password. > 2. Controller/Listener passes form vars to service layer. > 3. Service layer invokes BEAN and passes it to the DAO for population. > ERROR TYPE 1: user not found (Q: So how would you pass this ERROR back > to the view.). > ERROR TYPE 2: DB error (Q: Perhaps there was a table error or DSN > error or database was down. So how would you pass this ERROR back to > the view. Obviously you would want to email the administrator with the > specific error as well as provide a generic message to the user). > > Cheers > Matthew > > > -- Barney Boisvert [EMAIL PROTECTED] http://www.barneyb.com/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "CFCDev" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/cfcdev?hl=en -~----------~----~----~----~------~----~------~--~---
