Re: [Springframework-developer] Re: Lazy transaction creation

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Hi,

I have tested the LazyConnectionDataSourceProxy class
with a DataSourceTransactionManager manager, and
BeanNameAutoProxyCreator / TransactionInterceptor for
the weaving. It works fine!
I have tested too when the hypersonic database isn't
started on the load of the webapp but started on the
first call... It works fine too.
Thierry

> Lazy connection check added. If the eager check on
> startup fails, the first
> transaction on that DataSource will fetch a physical
> JDBC Connection on
> getAutoCommit and getTransactionIsolation to
> retrieve the actual defaults,
> keeping those default values from then on to be able
> to expose them without
> fetching a physical Connection.
> 
> Juergen
> 
> 
> -----Original Message-----
> From:
>
spr...@li...
>
[mailto:spr...@li...]On
> Behalf
> Of Juergen Hoeller
> Sent: Wednesday, January 12, 2005 8:46 AM
> To: spr...@li...
> Subject: Re: [Springframework-developer] Re: Lazy
> transaction creation
> 
> 
> Matt,
> 
> Regarding the issue with custom destroy methods:
> Indeed, the bean factory
> looks for them on the exposed object rather than the
> originally defined one;
> in your case, on the LazyConnectionDataSourceProxy
> instead of on the wrapped
> BasicDataSource.
> 
> This is not deliberate but rather an unfortunate
> side effect. I've just
> adapted AbstractAutowireCapableBeanFactory to detect
> this scenario and
> register the original bean objects as disposable
> beans (implementing
> DisposableBean or having defined a destroy-method)
> if necessary. The
> mechanism was already there, because of a similar
> problem with inner beans.
> I'll commit the change today; please give the next
> nightly snapshot a try if
> you have the chance!
> 
> I'll also add lazy
> defaultAutoCommit/defaultTransactionIsolation checks
> to
> LazyConnectionDataSourceProxy, kicking in when the
> check on startup failed.
> Note that you can also specify those defaults as
> bean properties: In that
> case, no check of a Connection will happen, as we
> assume that the specified
> defaults match those of the target DataSource.
> 
> Juergen
> 
> 
> -----Original Message-----
> From:
>
spr...@li...
>
[mailto:spr...@li...]On
> Behalf
> Of Matt Sgarlata
> Sent: Wednesday, January 12, 2005 1:31 AM
> To: spr...@li...
> Subject: [Springframework-developer] Re: Lazy
> transaction creation
> 
> 
> Juergen -
> 
> The LazyConnectionDataSourceProxy works great :)  I
> am using a
> BeanNameAutoProxyCreator to automatically apply
> transaction management
> to all of my Struts Actions, yet the Actions don't
> fail even if the
> actual database is not working, so long as they
> don't touch the database :)
> 
> One comment - I would suggest adding the ability for
> defaultAutoCommit
> and the defaultTransactionIsolation to be lazily
> fetched.  I'm guessing
> you're doing an eager fetch in the
> afterPropertiesSet method so that
> only a single connection need be retrieved when the
> context is refreshed
> rather than one connection when defaultAutoCommit is
> lazily fetched and
> a separate one when defaultTransactionIsolation is
> lazily fetched.  I
> think it would be best to have *both* your eager
> strategy and a lazy
> strategy available as a backup in case the eager
> strategy fails.  That
> way, if the DB is down when the application starts
> up but comes on line
> later, the defaultAutoCommit and
> defaultTransactionIsolation will still
> get set correctly.
> 
> I set up the LazyConnectionDataSourceProxy in the
> postProcessAfterInitialization method of a
> BeanPostProcessor (as
> suggested in the JavaDoc).  However, when I refresh
> my application
> context I'm getting errors:
> 
> ERROR
>
(DefaultListableBeanFactory:invokeCustomDestroyMethod)
> - Couldn't
> find a destroy method named 'close' on bean with
> name 'carlosPool'
> ERROR
>
(DefaultListableBeanFactory:invokeCustomDestroyMethod)
> - Couldn't
> find a destroy method named 'close' on bean with
> name 'dev2Pool'
> ERROR
>
(DefaultListableBeanFactory:invokeCustomDestroyMethod)
> - Couldn't
> find a destroy method named 'close' on bean with
> name 'devDatabasePool'
> 
> Obviously the problem is that the ApplicationContext
> is attempting to
> call the close method of the
> LazyConnectionDataSourceProxy instead of
> the close method of my underlying
> org.apache.commons.dbcp.BasicDataSource.  Is this
> considered a feature?
>   I would think it would be better for the close
> method of the unproxied
> class to be invoked rather than the close method of
> the wrapper object
> created by the BeanPostProcessor.
> 
> Matt
> 
> Juergen Hoeller wrote:
> > Guys,
> >
> > Please check out the following issue that I've
> just addressed:
> >
> >
>
http://opensource.atlassian.com/projects/spring/browse/SPR-572
> >
> > As I said in my comment, I've been wondering about
> this for a while and
> > finally took the occasion to implement a generic
> solution for it. A
> > particularly nice side effect is that it allows
> for efficient
> transactional
> > reads with HibernateTransactionManager, avoiding
> database communication
> > overhead if everything can be resolved in the
> second-level cache!
> >
> > I'll commit this in a moment, so feel free to give
> it a try.
> >
> > Juergen
> >
> >
> >
> >
>
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> 
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