Re: [Springframework-developer] JdoDialect and detach?

[Juergen H. <ju...@in...>]

Marc,

I'm actually in regular contact with Patrick myself; we usually keep each
other up-to-date on Spring/JDO things. Regarding attach/detach in
JdoDialect, there's probably some miscommunication there ;-) Patrick and I
have been talking about the need for this before, but no such thing has made
it into the Spring codebase yet.

Anyway, I'm leaning towards adding those methods in the meantime. Even when
JDO2 is final and mainstream, there might still be some reasons to override
the default attach/detach behavior in a vendor-specific fashion, for example
customizing the default fetch group or calling some vendor-specific
overloaded version of attach/detach. Alternatively, there's always the
option to implement custom JdoCallbacks based on vendor-specific PM API, of
course.

I've already refactored JdoTemplate and DefaultJdoDialect accordingly, but
not committed the changes yet. In the course of this, I've also added a
"newNamedQuery" hook to JdoDialect, factoring out named query creation too
(intended for pre-JDO2 named query support as found in Kodo, Lido, Versant
Open Access). In total, this should pretty much cover most functionality
that current JDO impls offer beyond JDO 1.0.

Juergen


-----Original Message-----
From: spr...@li...
[mailto:spr...@li...]On Behalf
Of Marc Logemann
Sent: Sunday, June 19, 2005 4:29 PM
To: spr...@li...
Subject: Re: [Springframework-developer] JdoDialect and detach?


Juergen Hoeller wrote:

> To make the actual behavior pluggable, we could factor the actual
> invocations out to corresponding new JdoDialect methods, by default
calling
> the standard JDO 2.0 methods accordingly. This could then be overridden
for
> special vendor-specific attach/detach methods, whether current JDO 2.0
> previews or overloaded vendor-specific versions alongside the standard JDO
> 2.0 methods.

+1, thats the approach i had in mind in the last days.

> Kodo currently has no-arg "attach" and "detach" methods. Versant Open
Access
> currently has "versantAttachCopy" with one or two boolean args, and
> "versantDetachCopy" with a String arg (the fetch group; can be null). Both
> could quite easily be used within a Kodo/Versant-specific JdoDialect,
> passing in default arguments where necessary.

And i know at least one more vendor which could be easily adjusted to
that as well.

> I'm certainly open to go down that route; I'm just a little undecided
> whether it makes sense to do it at this point of time. I'm currently in
the
> process of gathering some further opinions. If it turns out that the
general
> agreement is in favor of such hooks, I'll add them for Spring 1.2.2
> (scheduled for coming Thursday/Friday).

Yeah and here we will certainly have different oppinions. Most people
will think "hey JDO2 is nearly out the door - no need for dialect stuff
anymore". I can agree on this only to that point that this argument is
true and i dont believe this. I asked Patrick Linskey (or Abe White,
dont know anymore) from Solarmetric and he said that JDO2 is not THAT near.

Anyway, i am interessted to hear other oppinions on that issue. Perhaps
i will ask the Solarmetric guys about that to get some more arguments.
Really funny was a statement from Patrick to me where he believed that
there is allready an attach/detach abstraction inside JdoDialect, so it
seems he likes the idea so much that he thought its allready in there ;-)


--
regards
Marc Logemann
[blog] http://www.logemann.org
[busn] http://www.logentis.de


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