[hibernate-dev] Hibernate OGM

Wed May 11 11:24:20 EDT 2011

2011/5/11 Alex Snaps <alex.snaps at gmail.com>:
> Unintentionally left the ML out.

oops, sorry didn't realize that. for everyone else: please find my
previous reply below;

> Sanne, wrt jsr107 fair enough. I then feel that we should not leverage Map and use a custom type that only declare what's needed (and avoids the return value, when not required). I think that'd make it simpler, wdyt ? How should we name that thing ? My first attempt was GridMap...

So you need something like a Cache, but
1- avoid the org.infinispan package
2- provide non-return value methods (Infinispan does this setting
flags in the context to avoid an explosion of methods - does EHCache
have something similar?)
?

GridMap sounds fine, but again it's just a temporary solution until
non-grids are supported as well.
Other opinions ?

Sanne

> On Wednesday 11 May 2011 at 16:50, Sanne Grinovero wrote:
>> 2011/5/11 Alex Snaps <alex.snaps at gmail.com>:
>> > On Wednesday 11 May 2011 at 15:38, Sanne Grinovero wrote:
>> > Hi Alex,
>> > > thank you I'm having a look and will comment more on github directly.
>> > I'll look into your comments and will adapt. thanks!
>> >
>> > >
>> > > A first comment: I see that a big part of your patch is about
>> > > replaceing "Cache" with "ConcurrentMap" and renaming variables to be
>> > > consistent with this change; at the same time in the JSR-107 forum it
>> > > seems that everybody is agreeing on *not* extending Map, while there's
>> > > going to be something similar to a Map, this is going to be called
>> > > "Cache", so I'd stick with our current name.
>> > > I understand this is a bit in flux now and nothing is cast in stone,
>> > > but at the moment it would be better to keep your patch smaller and
>> > > avoiding these conversions, or at least keeping these refactorings as
>> > > a separate commit.
>> >
>> > I think that makes sense, I actually started with neither Map nor ConcurrentMap, but some other random Grib interface.
>> > I then saw the wiki page mentioning Map... I certainly can review this, but it does look like the plan is to have this tailored to jsr-107, I didn't know that. I'll stick to ConcurrentMap return values, but will not rename further.
>>
>> Sorry I didn't mean to state that we're going to support jsr-107, we
>> should discuss that but it's unlikely in practice as we want to
>> support more alternatives than key/value stores.
>> I'm only mentioning it as the abstraction you're introducing now will
>> make OGM support only Infinispan and EHCache, and they happen to have
>> this common API which gives names the building blocks as "Cache" and
>> "CacheManager". So for the time being there's no need to change all
>> variable names. It will definitely be more complex when other storage
>> engines will be added; it might be an option to use JSR-107 or JSR-347
>> at least for the key/value implementors but I don't think either is
>> going to cover all of noSQL.
>> Also even if we wanted to finish only Infinispan and EHCache, I don't
>> think the ConcurrentMap API would be good enough, we likely need a
>> more intrusive definition of "dialect" here.
>>
>>
>> > > The plan is to build the first version of queries on top of Hibernate
>> > > Search, so basically that's already an abstraction on top of any "Grid
>> > > implementation" and it should work fine with EHCache as well; Lucene
>> > > won't be able to solve all use cases though so for some cases we'll
>> > > need to tap into special functionalities offered by the grid provider,
>> > > but that's going to be a second step. Suggestions welcome of course!
>> > I have seen that Hibernate Search approach, I wondered whether a real query bridge to the grid wouldn't make more sense. But I totally agree that that approach makes total sense as a first step.
>> >
>> > >
>> > > As far as the "skip locking" pattern, that's currently the way to
>> > > build a sequence generator on top of Infinispan, in case of EHCache
>> > > you might want to suggest a totally different approach, I'd expect
>> > > that this should be an implementation detail at the dialect level, not
>> > > necessarily common code.
>> > Alright, that makes sense as well... I'll look into abstracting that nicely behind the Dialect then.
>> >
>> > >
>> > > Regards,
>> > > Sanne
>> > >
>> > >
>> > > 2011/5/11 Alex Snaps <alex.snaps at gmail.com>:
>> > > > Hey,
>> > > > I've taken some time and, in an attempt to port Hibernate OGM to use Ehcache instead of Infinispan, abstracted it from Infinispan.
>> > > > As the doc on that task states, I've made all calls use ConcurrentMap (rather than Map actually). I had a little trouble understanding the "Skip locking proposed by Sanne" in OgmTableGenerator.doWorkInCurrentTransactionIfAny, so that this does a simple Map.get now (that might have been a specialization for a Dialect, but couldn't understand what it was all about).
>> > > > And finally introduced a new hibernate.grid.manager prop to instantiate the proper provider...
>> > > >
>> > > > The changes are available here:
>> > > > https://github.com/alexsnaps/hibernate-ogm/commit/d0fcbffed4c4bcc2aa5208c049ca5e870e07424e
>> > > >
>> > > > Hope that can be made useful… I also wanted to start looking into queries next. But I'll send another mail on that later.
>> > > > Thanks,
>> > > > Alex
>> > > >
>> > > >
>> > > > --
>> > > > Alex Snaps <alex.snaps at gmail.com>
>> > > > Senior Software Engineer - Terracotta
>> > > > http://twitter.com/alexsnaps
>> > > > http://www.linkedin.com/in/alexsnaps
>> > > >
>> > > > _______________________________________________
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>> > > > hibernate-dev at lists.jboss.org
>> > > > https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>
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