[hibernate-dev] nested ServiceRegistry ?

[Adam Warski]

I think it's quite reasonable to have both app-wide and session factory-wide services.
Or you can call them "scopes", just like in a webapp you have request, session and app-scoped beans, here you can have app and session-scoped services.
Or even maybe (Hibernate) session-scoped ones? Although I'm not sure if they would be useful anywhere ;)

Adam

On Mar 22, 2011, at 3:27 PM, Steve Ebersole wrote:

> ServiceRegistry itself has worked out great imo, but I am starting to run into 
> difficulties in migrating certain things to be services.  Specifically I had 
> issues with both event listeners and Statistics.  In each case the issue was 
> slightly different, but both were solveable by having a notion of the 
> ServiceRegistry being scoped by the SessionFactory.  That is not the ideal 
> general solution though since many services do not care about or need the 
> SessionFactory.  The only real solution I have thought of is to have the 
> concept of a set of nested registries.  In the simpliest case, I think 2.. a 
> basic service registry and a session factory scoped one where the session 
> factory scoped one knows about the basic one (typical parent delegation).
> 
> But I am looking for any other suggestions.
> 
> Another option is that maybe listeners and stats are just not services in the 
> ServiceRegistry sense.  
> 
> So what were the specific problems?  I guess that is useful to formulate 
> suggestions ;)
> 
> In the case of statistics, its merely a case that it needs a reference to the 
> SessionFactory to be able to answer questions like "getEntityNames, 
> "getCollectionRoleNames", etc.
> 
> In the case of listeners it is not a simple explanation.  It really comes down 
> to scoping of the listeners and timing in regards to how stuff happens at the 
> moment because of the "freeness" of Configuration.  The end result was 
> different for each listener set.  jpa, envers, bean validation, search each 
> had unique set of problems; even the default listeners had issues.
> 
> ---
> Steve Ebersole <steve at hibernate.org>
> http://hibernate.org
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> hibernate-dev at lists.jboss.org
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-- 
Adam Warski
http://www.warski.org
http://www.softwaremill.eu