On Nov 29, 2007, at 10:56 AM, Aristedes Maniatis wrote:
* prePersist() is only useful as a place to set object attributes
(such as creationDate) since you cannot follow relations reliably
in a ROP environment.
True, and a workaround would be to support relationships for transient
objects. Something Kevin was bringing up on multiple occasions.
* postUpdate() and postPersist() are useful for changes which do
not need to be committed atomically with the original commit. So
good for creating log records, but not ideal for updating
invoiceOwing.
Another way to go about atomic commits is to set up a manual
transaction that spans a request scope. I think that's an appropriate
solution.
* postPersist() is badly named. It is really postInsert()
* we need preInsert()
per JPA "persist" is "insert", so the naming is correct if somewhat
confusing.
With some further reading of the JPA specification I have come to
the following conclusions:
* the JPA was written by lawyers who get paid by the word
It is confusing. Tell me about it! But partially because of
differences in perception of persistence between Cayenne and the
frameworks with EJB background.
* postPersist() is defined in the JPA to occur after a NEW record is
written to the database. Which is how Cayenne works.
Yep.
* pre/postUpdate(): the JPA specification is very very unclear, but
it looks like maybe it might apply for both new and existing
records. But then postUpdate() overlaps postPersist() which is a bit
pointless.
I think this is left up to implementation to handle. Yes - confusing.
* if preUpdate() is just for existing records we still need a
preInsert().
I wonder if we should just call "preUpdate" for new objects in
addition to prePersist.
Andrus
