[seam-dev] SAF (aka Entity Framework) idea in Seam 3

[José Rodolfo Freitas]

Ok, I'll try to do that today.

On Thu, Sep 22, 2011 at 2:13 AM, Dan Allen <dan.j.allen at gmail.com> wrote:

> On Wed, Sep 21, 2011 at 23:30, Lincoln Baxter, III <
> lincolnbaxter at gmail.com> wrote:
>
>> There are also other approaches, like "Active Record," but in my opinion,
>> the EntityManager poses a bit of a problem: It requires that it must already
>> know about the entity. And in my experience that is an inherently difficult
>> problem to overcome when attempting to build truly stateless applications -
>> resulting in duplicate calls to the database to fetch data that you already
>> have (just to sync things up.) While this is good for things like
>> transactionality, it is bad for performance, but before I get too far off
>> topic here, I'm just going to stop :) In a sense, we are fighting against
>> JPA combined with a Strongly Typed language. I think that the lambico
>> approach (annotating interfaces, like what Spring did - yep I said it) is
>> actually the best approach I've seen in a long time.
>>
>>
> The other point to make here is that the reason we need a class at all is
> because the EntityManager only gives us part of what we need. It certainly
> does CRUD. But it does provide transaction boundaries, it does not hold a
> reference to the active instance and some of it's methods require knowing
> the context (persist vs merge vs the implicit update). We don't necessarily
> want to hide the EntityManager, since a philosophy of Seam has always been
> to keep the native APIs exposed and unwrapped. But we do want to keep the
> developer's codebase dry.
>
> ...with that said, I'm fine with a "smarter" entity manager class that can
> be used as a delegate. But I do think there is merit in offering a class to
> extend for rapid development scenarios.
>
> Jose, could you make a gist for how you would create a bean for managing an
> entity instance using the composite pattern? I'm asking so we have something
> to contrast.
>
> (btw, the term EntityHandler sounds reasonable to me. Another approach
> Jason and I had was EntityInstanceManager, or *Handler. We want to
> distinguish between the EntityManager which manages all instances and a
> component that manages just a single instance).
>
> -Dan
>
> --
> Dan Allen
> Principal Software Engineer, Red Hat | Author of Seam in Action
> Registered Linux User #231597
>
> http://www.google.com/profiles/dan.j.allen#about
> http://mojavelinux.com
> http://mojavelinux.com/seaminaction
>
>
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