[seam-dev] Persistence Module Overview

[Stuart Douglas]

On Fri, Oct 15, 2010 at 11:17 AM, Stuart Douglas
<stuart.w.douglas at gmail.com> wrote:
> That is a good question.
>
> Currently the CDI specification does not allow interceptors on the
> methods level to override interceptors on the field level (I have

That should be bean level, not field level.

Stuart

> filed an issue for this), if @Transactional was an interceptor binding
> it would not be possible to override the behaviour of individual
> methods. Also it is not really desirable to make @TransactionAttribute
> an interceptor binding, and I think we should prefer
> @TransactionAttribute where possible, just so there is only one
> annotation users need to remember.
>
> Good point about the stereotype's though. I might add some trickery to
> the transaction extension to deal with this.
>
> Stuart
>
> On Fri, Oct 15, 2010 at 10:56 AM, Shane Bryzak <sbryzak at redhat.com> wrote:
>>  Great work, thanks Stuart.
>>
>> I was wondering about one thing though - why is @Transactional not an
>> interceptor binding?  The way it is now, you can't use it in a stereotype
>> (though you can probably use @TransactionalInterceptorBinding, but this is
>> in the impl module not the api, and having to use it instead of
>> @Transactional seems inconsistent).
>>
>> Shane
>>
>> On 15/10/10 09:05, Stuart Douglas wrote:
>>>
>>> I just though I would send out a quick overview of exactly what is in
>>> the persistence module at the moment:
>>>
>>>
>>> Transactions:
>>>
>>> It provides a SeamUserTransaction object that extends the JTA
>>> UserTransaction (this means a dependency on the jta API).
>>>
>>> Three default implementations will be provided
>>> - The default EE version that either looks up UserTransaction in JNDI
>>> or retrieves it from the EJBContext if a CMT is active
>>> - An implementation that uses EntityTransaction, this is retrieved from
>>> the SMPC
>>> - An implementation that uses hibernate's transaction API (to be done)
>>>
>>> It does not use the CDI's ability to inject the UserTransaction for a
>>> number of reason:
>>> - It is not available in all environments
>>> - It is not available in EJB's that use CMT
>>>
>>> It provides a transaction interceptor, this allows you to use
>>> @TransactionAttribute on managed beans the same way you would on
>>> EJB's.
>>> It provides @Transactional and @SeamApplicationException for
>>> environments where these API's are not available.
>>>
>>> Managed Persistence Contexts
>>>
>>> - Defined as follows:
>>>
>>> @SeamManaged
>>> @Produces
>>> @ConversationScoped
>>> @PersistenceUnit("myPu")
>>> EntityManagerFactory enf;
>>>
>>> - This will work even in environments where @PersistenceUnit injection
>>> is not directly supported, as seam-persistence will bootstrap it for
>>> you.
>>>
>>> - The SMPC provides the following:
>>> - Automatic transaction enlistment
>>> - Ability to use EL in queries
>>> - Automatic hibernate search integration, if available
>>> - Ability to set manual flush mode if required
>>> - Event is fired when the SMPC is created, to allow for additional
>>> configuration such as adding hibernate filters.
>>>
>>> It also provides @TransactionScoped for transaction scoped beans
>>> (forgot to put this in the reference guide, oops)
>>>
>>> There are currently tests for jboss-as, jetty, and jetty+openjpa (with
>>> no hibernate classes present on the classpath). I am planning on also
>>> adding glassfish, glassfish+hibernate, and probably a few more as
>>> well.
>>>
>>> I have also added seam managed transactions to the faces module, this
>>> is similar to seam 2, however it has two notable improvements:
>>> - It can be controlled on per view basis (including using wildcards)
>>> - it can be enabled only for the RENDER_RESPONSE, so you have manual
>>> transaction control in your business logic, and then seam opens a
>>> transaction for you when rendering to prevent LIE's (this also can be
>>> configured on a per view basis).
>>>
>>> I think that just about covers it. If anyone has any questions or
>>> comments fire away.
>>>
>>> Stuart
>>> _______________________________________________
>>> seam-dev mailing list
>>> seam-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/seam-dev
>>
>>
>