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[jsr338-experts] Re: Inheritance of Extended Persistence Context

  • From: Scott Marlow <smarlow@...>
  • To: jsr338-experts@..., Linda DeMichiel <linda.demichiel@...>
  • Cc: Emmanuel Bernard <emmanuel.bernard@...>
  • Subject: [jsr338-experts] Re: Inheritance of Extended Persistence Context
  • Date: Wed, 20 Jun 2012 09:52:08 -0400

On 06/18/2012 05:34 PM, Linda DeMichiel wrote:
Hi Emmanuel, all,

On 6/4/2012 2:58 AM, Emmanuel Bernard wrote:
Hey all,

I am of the opinion that both DAOs should share the same persistence
context as they are both wrapped in the same Stateful SessionBean. Is
there any reason why we should purposely not propagate the same
persistence context?

While I understand the propagation and the reasoning, I do think that
it "makes sense" for implementors and is sound but nevertheless miss
the ease if use and practical test especially for beginners.

It would be much easier for people to understand that SFSB sharing the
same life cycle owner (the top SFSB in practice) share the same
persistence context.
PC propagation and inheritance is quite complex to grasp despite the
fact that we designed it to improve ease-of-use. I wonder if we can
make it easier for people.

Sure, the "fix" is one line of code, namely add the @PC to the root
SFSB but the behavior is surprising and more than one beginner falls
into the trap of not adding it and end up using 2 PC with at best
performance issues and worse case, hard to understand identity breaks.

Christian has expressed my opinion with stronger words but fairly
aligned with my ideas
http://4thline.org/articles/Stateful%20persistence%20context%20propagation%20in%20JPA.html



OK, but this would be an incompatible change, which I don't think we
should contemplate.   Depending on further
input from developers on this issue, we could consider whether
addressing the use case by means of additional
metadata would be beneficial.


Vendors could use an extension to switch between the two extended persistence inheritance techniques. That could give some developers, a concrete way to experiment with both inheritance techniques (single level parent only or recursing up/across multiple levels).

My preference is to add the metadata for JPA 2.1, rather than vendors using an extension.

Scott



[jsr338-experts] Re: Inheritance of Extended Persistence Context

(continued)

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/01/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/01/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Linda DeMichiel 06/01/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/07/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Linda DeMichiel 06/18/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Emmanuel Bernard 06/04/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/07/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Werner Keil 06/07/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/11/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Linda DeMichiel 06/18/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/20/2012

[jsr338-experts] Re: Inheritance of Extended Persistence Context

Scott Marlow 06/01/2012
 
 
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