Re: opening multiple databases from same program

You can have a Swing desktop application and work with many threads. You can 
send the Swing event thread a command with the  EventQueue.invokeLater 
function. You can also send a command from the Swing event thread to your own 
threads, implementing the same mechanism, which is used by the EventQueue 
class. This will be much easier than changing the SimpleORM source code. And 
it is much more flexible. For example, your swing application is still able to 
react, when a long drawn database sql-statement is executed. In the Java 
standard library you can find everything you need to implement such a solution.


Thomas



Am Dienstag, 21. September 2010, um 14:33:29 schrieben Sie:
> I'm effectively running several smaller apps inside the same Java VM.
> Each app has it's own database.
> Since this is a Swing desktop application, most of the action happens on
> the Swing event dispatch thread. This means that I end up talking to
> multiple databases from the same thread, triggering the check.
> 
> Sigh. I keep having this problem.
> Everybody is developing web-applications these days, which means that all
> of the ORM frameworks are designed around the HTTP request-response cycle.
> I ended up dumping Hibernate because it won't play nice with desktop
> applications.
> 
> Luckily SimpleORM is relatively straight-forward code, so I'm probably just
> going to run my own private branch of it, since my changes don't seem to
> meet with popular approval.
> 
> -- Noel
> 
> [email protected] wrote:
> > It is actually possible to dissassociate sessions from threads, and thus
> > have several. But that is a very odd thing to want to do. What are you
> > trying to achieve?
> > 
> > (Ususally trying to open a session on a thread that already has an open
> > session means that you did not close the previous session, leading to a
> > connection leak, which is why SimpleOrm fails fast.)
> > 
> > Anthony
> > 
> > At 02:02 AM 10/07/2010, you wrote:
> > >Hi,
> > >
> > >well, AFAIK, you can't do that... !
> > >
> > >SSessionJdbc has built-in checks that a connection is single threaded
> > >using a ThreadLocal object. [I think Hibernate has some kind of best
> > >practice to achieve the same goal (I'm not formal here, I didn't use
> > >hibernate for years)]
> > >
> > >There is only one dataSource per SSessionJdbc and one SSessionJdbc per
> > >thread.
> > >
> > >You could implement a different strategy to handle this part. Some work
> > >was done along this path in a previous version of Simpleorm, for using a
> > >single JTA transaction per session. But it is not maintained.
> > >See simpleorm/extras/SConnectionEJB.java
> > >
> > >My question would be : what are you trying to achieve ?
> > >
> > >Franck
> > >
> > >Le vendredi 09 juillet 2010 à 17:11 +0200, Noel Grandin a écrit :
> > >> Hi
> > >> 
> > >> I'm opening multiple different databases from the same thread, which
> > >> is triggering this check:
> > >> 
> > >> simpleorm.utils.SException$Error: Thread's SSession already open [SS
> > >> 1.SkyMon]
> > >> [0@17:08:40.976] !SE>: at
> > >> simpleorm.sessionjdbc.SSessionJdbc.innerOpen(SSessionJdbc.java:129)
> > >> [0@17:08:40.976] !SE>: at
> > >> simpleorm.sessionjdbc.SSessionJdbc.open(SSessionJdbc.java:88)
> > >> [0@17:08:40.976] !SE>: at
> > >> simpleorm.sessionjdbc.SSessionJdbc.open(SSessionJdbc.java:108)
> > >> 
> > >> 
> > >> What do I do?
> > >> 
> > >> Thanks, Noel Grandin
> > >> 
> > >> 
> > >> 
> > >> 
> > >> 
> > >> 
> > >> 
> > >> __________________________________________________________
> > >> Disclaimer:
> > >> <http://www.peralex.com/disclaimer.html>http://www.peralex.com/discla
> > >> imer.html
> > 
> > Spreadsheet Detective,
> > Southern Cross Software Queensland Pty Limited
> > 54 Gerler Street
> > Bardon, Queensland 4065, Australia.
> > 
> > Email: [email protected]
> > <mailto:berglas%40spreadsheetdetective.com> www.SpreadsheetDetective.com
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> > 
> > "If the model seems correct only because the numbers look right,
> > then why build the model in the first place?"
> 
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