> 1) form beans generally should consist of String data to facilitate > round-tripping of invalid inputs. I like to constrain them to a clearly > defined role of marshaling data 'into' and 'out of' the > presentation layer, > i.e. across the boundary between presentation and application.
This i would agree with. Fields in BO/VOs have various types. ActionForms should only get/set strings. > > 2) value objects should use typed interfaces to ensure marshaling to and > from presentation format (string types) is pushed as far up the > application > stack as possible. This also enables other, potentially type-aware, > presentation / client tiers to be built on top of the same value objects > (e.g. for a web-services interface). > > To address Micheal's question (why not just make value objects > and business > objects the same thing?), I'd point out that it can be valuable to > distinguish between business rules and application logic. I find my > business objects often have functionality I don't want called > directly from > the presentatin layer, particularly when using a mediation layer between > the two. > > Essentially, though, it comes down to the complexity of the > problem vs. the > complexity of the solution. The more complex the application, the more it > makes sense to partition responsibilities. For very simple > applications it > makes sense to collapse layers together. I tend to merge BO,VO,and DAO all into one bean. I made a self-persistable base bean (using OJB), and then just add fields with getters/setters. All works nicely. Add any simple logic into the beans. Stick complex logic in managers/helpers/services. I tend to pass these beans straight up to jsps for pure displaying of stuff, but then use actionforms to edit/submit data. A big timesaver can be to write a constructor for an action form that accepts a BO and fills itself from that. Daniel. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
