On Dec 23, 2007, at 6:05 AM, Aristedes Maniatis wrote:
Since the method for setting defaults in the db is the same accross
the database depending only on field type I can put together
something like the following to initialize objects following our
rules... still it does not work ROP :( PersistentObject used for
client seems to have no way to access the metadata like
CayenneDataObject does, i.e. no getObjEntity()
Yeah, anything you do with this will need to be server side, not in
the client. But lifecycle events work only on the server anyway, and
only once you've committed the object from the client. The code you
posted could go into the common superclass for your persistent
objects on the server. Catch the lifecycle event (either preUpdate
or prePersist) and fire off your code.
http://cayenne.apache.org/doc/lifecycle-callbacks.html
Yep, looks like defaults extraction can be done in a generic fashion,
and be abstracted in a single listener (or persistent superclass). I
prefer listener, as it wouldn't have to store shared state in static
variables. BTW, this could be a nice addition to Cayenne core down the
line (we can support runtime defaults extraction via DbAdapter).
On the ROP end for now invalidation with RefreshQuery maybe the only
way to get the defaults from the server, but eventually we'd like to
implement a smarter protocol that would pass any custom changes made
via callbacks and listeners on the server back to the client.
Andrus
