I too have written such a layer. The way it works for me is through the use
of mainly 3 interfaces (PersistenceSession, PersistenceTransaction,
PersistenceHelper) which are fronted by various factories.
PersistenceSession is really pretty analagous to PersistenceTransaction
except that it holds some additional (mainly user-related) data.
The idea is that a consumer (in my set up a SessionEJB service layer)
obtains a PersistenceSession instance. From the session, they can:
1) start/commit/rollback a transaction
2) obtain a (transacted) PersistenceHelper.
The PersistenceHelper simply exposes the CRUD and lock activities of the
underlying persistence platform.
I too, unfortunately, cannot send you the source but am willing to answer
some questions.
|-----Original Message-----
|From: Mahler Thomas [mailto:[EMAIL PROTECTED]]
|Sent: Wednesday, September 11, 2002 8:30 AM
|To: 'OJB Users List'
|Subject: AW: The OJB JDO implementation is not finished,
|how can I start
|u sing OJB?
|
|
|We have such a layer working in my company. Unfortunately
|is is closed
|source :-(
|The basic idea is very simple:
|1. have Transaction interface. providing methods like
|begin(), commit(),
|abort() lockRead(...), lockwrite(...), getObjectByQuery(Query),
|getCollectionByQuery(Query), etc.
|2. write a OJB ODMG Implementation of this interface.
|3. write a TransactionFactory that serves TransactionOjbImpls.
|
|cheers,
|Thomas
|
|> -----Urspr�ngliche Nachricht-----
|> Von: Max Rydahl Andersen [mailto:[EMAIL PROTECTED]]
|> Gesendet: Dienstag, 10. September 2002 22:18
|> An: [EMAIL PROTECTED]
|> Betreff: The OJB JDO implementation is not finished, how
|can I start
|> using OJB?
|>
|>
|> This question is listed in the faq and I think I understand
|> the most of the
|> answer - but does someone have a concrete example of
|"Using your own
|> Transaction interface in conjunction with the OJB query api
|> will provide a
|> simple but powerful abstraction of the underlying
|persistence layer."
|>
|> /max
|>
|>
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