Hi,

is there any way to find out if a given object is still up to date without detaching it and later merge etc? Or is the common practise not to know and let optimistic locking produce an exception upon commit if it has changed in the database?

But then what if I just want to make sure that the object is up to date for displaying purposes? Is there some sort of command I could execute right before the end of my unit of work? It would even be enough if I could circumvent the session (cache) and just retrieve the same object fresh out of the database and simply check key properties of it to see if I need to adjust my object to be displayed...

thanks

you could use a version-property. Then you would compare your local version with the current version in the db.

Thanks for the reply.

What good would a version property to in this case? I mean once I load an object from the database it is cached in the persistence context. Every subsequent load would simply return this chached reference ... not a new (probably more recent) object.

An example. A long running transaction. To get my point across lets say ... 10 minutes(I know this wouldn't/shouldn't happen in any production code)

Thread A loads object ID:1 after the transaction starts then continues doing whatever for 10 mins...
In the mean time Thread B also loads object ID:1 and quickly changes a couple of attributes then commits them.
Thread A doesn't change any attributes on its object. It just needs to display them. So now there is no way it can display the most recent version of this object since it only has "access" to the chached one from 10 minutes ago.

I hope I didn't explain it too complicated. So, is there a way to retrieve a fresh object from the database even if one has already been loaded to the persistence context?

From API documentation:



Edit: Just discovered a warning, but I don't know the reason for it...

Thanks,

It works. I'm going to propose this as a possibility and see if it gets accepted.