Yeah, I understood the hint :-)
On Jan 7, 2008, at 5:10 PM, Philip Miller wrote:
That nudge should have been for rollbackChangesLocally() - CAY-716.
Sorry Andrus.
-----Original Message-----
From: Philip Miller [mailto:[EMAIL PROTECTED]
Sent: 07 January 2008 14:29
To: [email protected]
Subject: RE: Selective commit
Nested data contexts may also help you to isolate atomic
changes to the object graph. Especially when the
commitChangesLocally() method is implemented (nudge ;). Check
out DataContext.createChildDataContext().
-----Original Message-----
From: Andrus Adamchik [mailto:[EMAIL PROTECTED]
Sent: 07 January 2008 13:32
To: [email protected]
Subject: Re: Selective commit
Hi Álvaro,
It is hard to give a precise advice on multithreading
without knowing
the nature of your application. So here is a few general notes:
* DataContext instance is your isolated area for making in-memory
changes to objects that will all be committed at once. So consider
using multiple contexts as appropriate.
Cayenne docs recommend various common patterns, such as DataContext
per session (i.e. each user has a dedicated context),
DataContext per
request, or DataContext per application (in a read-only
app). You can
also devise your own approach, if none of the above fit your needs.
All you need to know here is that multiple threads *reading* from a
shared DataContext is ok, but multiple threads *writing* to
a shared
DataContext is not ok.
* In a rare case if you really need multiple threads to work off of
the same context, consider using a dedicated nested DataContext for
each atomic object modifications.
Andrus
On Jan 7, 2008, at 2:44 PM, Álvaro Martínez wrote:
Hi, I've been working for a while with Cayenne but never
realized I
had a problem... until I got a weird exception.
The fact is that I had been using context.newObject() and
context.commitChanges() to create new rows in the
database. But my
application works with many threads, so global commits
can (and in
fact do) interrupt normal creation of objects. Thread A and
Thread B
are creating objects and filling their fields, but then B
commits all
and A throws a validation exception because mandatory fields are
missing.
How could I commit only one object?
Thanks,
Álvaro from Spain (Push the button Inc.)
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