just FYI I was planning on writing a PB session bean soon. I haven't started yet
though, so if you want to do it, just let me know so we don't replicate work.
m
-----Original Message-----
From: Mahler Thomas [mailto:[EMAIL PROTECTED]]
Sent: Wed 9/11/2002 8:41 AM
To: 'OJB Users List'
Cc:
Subject: AW: J2EE client/server...
Hi again,
> Hi!
>
> Im just sitting here and examining the sourcecode (even more
> :) and some
> questions popup...
welcome in OJB land!
> I have found the PersistenceBrokerServlet and was examining
> how one could go
> about realizing such a "beast"
> in a Stateless SessionBean, but I quickly found that this is
> actually not
> what I want to have in my scenario :)
>
> I do not want to have the "raw" PersistenceBroker interface
> on to the client
> and I do not like to have the persistencelayer do things the
> J2EE container
> should do for me :) (e.g. loadbalancing and global cache issues)
> I would much rather have a sessionbean on which I could have
> create, read,
> update and delete vanilla java object and objects - and on
> this sessionbean
> place e.g. my own securitylayer.
>
> Is this possible to do safely when I only want the J2EE (and
> hereby JDBC and
> hopefully also OJB's) transaction to cover one single method.
> e.g. If a
> client have a sequence of calls: read(x), read(y), read(z),
> update(x,y,z)
> then each method has its own transaction.
>
should be possible
> Does the ODMG implementation remember forever that a client
> has read an
> object ?
> What if this client disconnects abruptly ? When is the
> readlock released ?
in OJB.properties you can set a lock timeout.
> Will the update(x,y,z) succeed if the first line in that
> method just tries
> to aquire a writeLock before it call store ?
If you succeed to get the write lock there should be no problems in writing.
> Can I enable optimistic locking and then have the advantage
> from both worlds
> ?
yes.
> e.g. ensure consistency across threads AND be notified if someone have
> read/write'd before my update succeeds ?
should be possible.
> And what will happen when my application starts to use J2EE
> clustering ?
> Will the ODMG locks that is stored in the database save me ?
yes!
> e.g. there will
> be no need for a distributed cache ?
exactly!
cheers,
Thomas
>
> /max
>
>
>
>
>
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