Hi Nikolai,

I also agree that it would be great to include transactions in our samples. 
Obviously part of that involves enlisting XA resources with the transaction 
manager. I believe that the best way to do this is, as Alasdair says, to adapt 
the XADataSource into a vanilla DataSource, with some automatic logic to enlist 
the XAConnections in active transactions.

JPA does make use of a JTA DataSource in managed environments, but the JPA 
provider expects to be provided with a DataSource that is automatically 
enlisted, not an XADataSource. This is another reason why the implementation 
Alasdair suggests would be useful. We could then re-use one implementation 
throughout Aries, rather than having a specific implementation for the JPA 
container. 

As far as I am aware there is no implementation that provides this behaviour in 
Aries, so it would definitely be welcome if you wanted to provide it.

Regards,

Tim



> Date: Wed, 13 Jan 2010 14:25:35 +0000
> Subject: Re: Transaction samples
> From: [email protected]
> To: [email protected]
> 
> Hi Nikolai,
> 
> I agree we definitely need to have a sample showing how transactions
> work. I had been thinking of updating the blog sample to include
> transactions, but nothing immediate. If you want to go ahead and
> either update the blog sample, or introduce a new one I think that
> would be great.
> 
> Since you mention the JDBC specification for derby I think it would be
> good to have an implementation of this. It would be really nice if it
> could adapt the XADataSource into a DataSource so the client would
> just use the DataSource API, and would implicitly get the transaction
> enlistment. I would do this separately from the sample and the derby
> bundle you mention.
> 
> I'm not sure I can answer your JPA question, but other will be able to.
> 
> Thanks
> Alasdair
> 
> 
> 2010/1/13 Tankov, Nikolai <[email protected]>:
> > Hi,
> >
> >  I was checking the examples and saw that there are no examples which 
> > demonstrate how transactions (JTA Transaction Services Specification) and 
> > DB drivers (JDBC Service Specification) can be used.
> > Do you plan to include transactional scenario in one of the existing 
> > examples? If no I can extend Derby bundle with an implement of interface 
> > org.osgi.service.jdbc.DataSourceFactory defined into OSGi enterprise spec. 
> > After that I can use it together with the existing transaction 
> > implementation in a simple example.
> > What do you think about this idea?
> >
> > The implementation of JTA DataSource for JPA is also interesting. Are there 
> > any plans for an implementation? Or it is implemented but I did not found 
> > it :)
> >
> > Thanks!
> >  Nikolai.
> >
> >
> >
> 
> 
> 
> -- 
> Alasdair Nottingham
> [email protected]
                                          
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