Re: ChangeNotification framework and Custom EO layout

Thanks a lot Pierce. Is [spread] an ObjC framework?

----- Original Message ----- 
From: "Pierce T.Wetter III" <[email protected]>
To: "YL" <[email protected]>
Cc: <[email protected]>
Sent: Thursday, April 14, 2005 2:33 PM
Subject: Re: ChangeNotification framework and Custom EO layout

       On Apr 14, 2005, at 1:04 PM, YL wrote:

             | Forgive me asking questions that may not so fit to this
mailing list.

              |I found no help for quite long, of the challenges
encountered.

              |David Neumann's ChangeNotification framework worked very well
for most
              |of apps untill i changed
              |my EO layout (indention shows the super-sub class
relationship) below:

              |EOGenericRecord (from EOF)
              |     EObject       // Shared logic/mechanism/utility/service
for all my EO's)
              |           ModeledCustomRecord  // EOModeler generated, for
entity Person, the class is _Person.
              |                MyCustomRecord     // For entity Person, the
class is Person (subclass of _Person)

              |From development view point, EObject reduces lots duplicate
efforts
              |and make the code much easier to
              |manage. I still use WO4.5.1 ObjC so that without java
reflection,
              |EObject knows the type of my
              |MyCustomRecords class and instances and do the right things
as I
              |expected. I'm using EObject to make
              |the class evolution mechanism working.
              |    The seperation between ModeledCustomRecord  and
MyCustomRecord
              |makes model updates more easier from developers' view point.

              |But ChangeNotification framework not work with the EO layout
above.
              |Could someone please give me
              |some hints so that I can get things fixed? Thanks for your
time read
              |this email.

          I don't remember the details of how the ChangeNotification
framework
       works, but if you invalidate using an EOGlobalID, your object
hierarchy
       shouldn't matter.

         What we do instead of the ChangeNotification framework is we use
       something called "spread" to allow broadcasting global IDs using
       NSArchiving between our many (30?) application instances. A thread
       listens to the spread broadcasts and stores them in a queue, which
each
       app instance sucks dry about once every 5 minutes and invalidates.

         (This is all in WO 4.5).

         BTW, ObjC has a certain amount of reflection. It just that the
methods
       haven't be collected into an API, but they're there. In EOF where you
       can also query the model about the entities as well which goes beyond
       Java.

         Pierce