Re: Three tier layered application using Wicket + Spring + Hibernate. How would you handle transactions?

[Timo Rantalaiho <Ti...@ri.fi>]

On Tue, 10 Feb 2009, Kent Larsson wrote:
> I'm thinking about using the **Open Session In View (OSIV)** filter or
> interceptor that comes with Spring, as it seems like a convenient way
> for me as a developer. If that's what you recommend, do you recommend
> using a filter or an interceptor and why?

What do you mean with an interceptor? If it's Spring-MVC 
specific, it cannot be used with Wicket. A Wicket equivalent 
would be a custom request cycle I suppose.

OSIV servlet filter should work OK.

> I'm also wondering how it will mix with **HibernateTemplate** and if I
> will loose the ability to mark methods as **@Transactional(readOnly =
> true)** etc and thus loose the ability to get some more fine grained
> transaction control?

It depends on what exactly you have the filter do. If you
have the Hibernate transaction manager of Spring, all Spring
*Templates should play nicely with that. Often the filter is
only made to defer closing a session until the end of the
request and transactions must still be started explicitly.
Check out what the filter code does (and how it can be
configured).

> Is there some kind of best practice for how to integrate this kind of
> solution with a three tier architecture using Hibernate, Spring and
> Wicket?

No :)

  http://www.satisfice.com/blog/archives/27

There are a lot of good examples though, the one James
posted is probably good and you should be able to find more
by searching the Wiki and this list in Nabble.

> If I use OSIV I will at least never run into lazy loading exceptions,

Not exactly. You can easily run into lazy loading exceptions
if you store your lazy-loaded objects for more than one
request and then try to access their lazy properties during
and different session than the original one.

> on the other hand my transaction will live longer before being able to
> commit by being uncommitted in the view as well.

What do you mean with this exactly?

Best wishes,
Timo

-- 
Timo Rantalaiho           
Reaktor Innovations Oy    <URL: http://www.ri.fi/ >

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