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From Mike Kienenberger <>
Subject Re: Session Replication
Date Wed, 05 May 2010 21:10:16 GMT
Hmm.   Unfortunately, I can't remember if my issue with that project
was that the DataContext wasn't being serialized or that it was and I
didn't want it to.  And this was 1.2, so the behavior may have changed
since then.

But in either case, it seems pretty trivial.

In the case of it being serialized, it already does what you want

In the case of it not being serialized, you'd create a new DataContext
and dump in all of the serialized objects you had from the original

I don't think there's any state that needs to be saved for a
DataContext other than the DataObjects it contains.   Maybe you'd also
need to save the initial fetched object snapshots if you were working
with optimistic locking.

All I can say for sure is that I did a JSF project where we saved the
uncommitted DataObjects out as client-side data (serialized into the
generated html), then read them back in on the next request.   The
data would survive application restarts, so it should be equivalent to
moving it to another session or another server.

I tried glancing through what project source code I had laying around,
but I couldn't find the code that dealt with the serialization -- too
many project modules to look through.

On Wed, May 5, 2010 at 4:57 PM, Michael Gentry <> wrote:
> My experience with Tapestry (4 & 5) serializing a DataObject to the
> HTML (which it does by default when you have a loop in a form) is that
> the deserializing of the DataObject (on the subsequent
> request/response) gives you a DataObject that is disassociated from
> the DataContext (not good).  Perhaps if the DataContext went along for
> the ride all would be well ...
> Thanks,
> mrg
> On Wed, May 5, 2010 at 4:53 PM, Mike Kienenberger <> wrote:
>> No direct experience, but I know you can serialize DataObjects and I'm
>> 99% certain you can serialize DataContexts.   I think I did this in
>> one project in the past to preserve state between requests rather than
>> saving state in the sessions.
>> On Wed, May 5, 2010 at 4:37 PM, Michael Gentry <> wrote:
>>> Someone on another project here asked me if Cayenne works with session
>>> replication (with 1+ user DataContext objects in the HttpSession)
>>> between application servers (such as JBoss).  They have a project
>>> where they are running N instances of JBoss and they replicate/sync
>>> the session data across the JBoss instances.  They are curious if the
>>> DataContext + DataObjects will replicate correctly.  I've never
>>> attempted to do so and am not sure.  Does anyone have experience with
>>> this?
>>> Thanks!
>>> mrg

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