Hi Mark, Mark Howell wrote: > Hello, > > Is there a way to force the PB to *not* share local instances of an > Object that it finds with multiple threads? I would prefer, for at > least some of my classes, that one thread not see the changes made by > another unless that object was specifically stored in the PB.
1. you can tell OJB (in OJB.properties) to use the EmptyObjectCacheImpl. This cache does not hold any references and thus avoids the problem you mention. 2. You could implement your own cache, that internally maintains a separate cache for each thread. 3. You can make your threads work with local copies rather than globally shared instances. After loading an instance with the PB call PB.removeFromCache(instance); If other threads load the same object they will be served with a fresh copy of instance. Of course you should use optimistic locking to avoid write conflicts. > > Would I need to use the ODMG API to do this currently? Of course ODMG does most of the work automatically. But as mentioned above, you can also do this with the PB. > If so, can I use > the PB API and ODMG concurrently on the same repository/db? > yes! There is a sample for this in faq.html. cheers, Thomas > Thanks, > Mark > > Thomas Mahler wrote: > >>Kevin Viet wrote: >> >>>If two threads query the API for this object, they share the same >>>reference on this object. >> >>correct. >> >> >>>So if a thread change a value (without update the object through the >>>API) of the object, the other thread will see this change (even for the >>>object cache) >> >>correct for PB API. For ODMG we have a pessimistic locking that will >>protect against such conflicts. >> >> >>>Won't any problem arise if thread1 change some values and thread2 is >>>commiting the update. >> >>correct >> > > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > > > > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
