Yeah, probably need to think about it. At the same time it is great when new extensions are created on top of Cayenne "platform", so if you implement an open source key-value-coding extension package solving specific problems, definitely mention it to the community.
Cheers, Andrus On Jan 31, 2011, at 3:22 AM, Andrew Lindesay wrote: > Hi Andrus; > > Thanks for getting back to me on this one. Your comments do make sense and I > think that in order to maintain focus on the "persistence framework" and > maintain consistency, it may be best to remove "readNestedProperty" on CDO. > > cheers. > > (Andrus) >> Sorry for delayed reply. >> >> The current set of accessors 'readProperty'/'readPropertyDirectly' exists >> for the benefit of the framework. 'readNestedProperty' is in a different >> category - it is a utility method and is never used by Cayenne internally >> (not counting unit tests). FWIW, I'd be willing to deprecate >> 'CDO.readNestedProperty' and just keep its static version in the utility >> class. So an inconsistency you pointed to - 'readProperty' being limited to >> mapped properties, while 'readNestedProperty' being a mix of mapped and >> unmapped properties, to me is purely a *naming* inconsistency. >> >> With that in mind us not having the suggested extra methods in Cayenne >> shouldn't prevent the customizations that you have in mind ... I think (?) >> You can always create a custom common superclass with a custom path >> navigation strategy, ignoring 'readNestedProperty' if it gets in the way >> (MyDataObject extends CayenneDataObject), but I am not convinced Cayenne >> should be the place for this code. It is a persistence framework, and >> staying focused on persistence is important IMO. >> >> We had a discussion in the context of 'cayenne-lifecyce' recently on what >> should be in Cayenne core, and what is an "extension". I think here we are >> down to this choice also. >> >> Let me know if I am still missing the point of your suggestion. > > (Andrew) >>> I've been playing around with trying to override some behaviours in the >>> area of "read property" on the data objects, but I think I have come to the >>> conclusion that the way it is rigged-up makes this a little difficult. I'd >>> like to suggest a change (which is probably more appropriate for 3.1 owing >>> to it being a non-trivial change in behaviour) and I would be interested in >>> any feedback. Here is the text of the ticket... >>> >>> --- >>> >>> There is an issue that a data object (DO) uses the "readProperty()" method >>> in its accessors such as "getStartTimestamp()"/"getArtist()" etc... The >>> "readNestedProperty()" does some extra things like using reflection to get >>> at non-modelled accessors, but "readProperty()" does not. This is an >>> inconsistency. >>> >>> Simply adding the additional reflection to "readProperty()" is not a good >>> idea because in the case where an object is not yet related to the model, >>> an infinite loop can result. Particularly in the case where a data object >>> is not yet added to an object context, the logical condition around >>> stopping this infinite loop is not able to be identified. >>> >>> My suggestion is to add a protected "readPropertyStored()" which will be >>> used by the accessors such as "getStartTimestamp()"/"getArtist()". This >>> method will ~not~ use reflection, but "readProperty()" will do the >>> additional reflection if necessary. The "readPropertyStored()" will >>> continue to invoke "readPropertyDirectly()". >>> >>> In addition, the "extra reflection" from "readProperty()" would be serviced >>> through two additional methods on the data object; >>> >>> readPropertyDerived(..) >>> >>> For the case of the "readNestedProperty(..)" the use of reflection into an >>> object which is ~not~ a data object will be serviced through; >>> >>> readNestedPropertyFromNonDataObject(..) >>> >>> Together these changes will allow for consistenecy in the 'read property' >>> behaviour and will also allow third parties to more easily extend Cayenne's >>> 'read property' behaviors in order to support more sophisticated 'read >>> property' behaviour. >>> >>> This is a change in behavior and generated DAO classes would need to be >>> modified to use 'readPropertyStored()' instead of 'readProperty()'. > > -- > Andrew Lindesay > www.silvereye.co.nz >
