[jboss-as7-dev] [infinispan-dev] AS7-4007 missing Infinispan dependency for clustered JPA second level cache

[Scott Marlow]

On 03/06/2012 02:27 PM, Galder Zamarreño wrote:
> So, to summarise all of this. What I suggest is this:
>
> - Short term:
> The "quick fix" I suggest in http://lists.jboss.org/pipermail/infinispan-dev/2012-March/010317.html

Do we want to try this (requires a new build of Infinispan I think)?  Or 
should applications workaround the issue until we can reach the 
medium/long term?

>
> - Medium term:
> Have a way to pass in marshalling configurations per cache manager and per-cache (or an abstraction of it), which allows the right class resolver to be passed in. (***)
> https://issues.jboss.org/browse/ISPN-1367

ISPN-1367 is targeted to Infinispan 5.2, any idea of the target release 
date for that?  I'm curious as to which AS release it might align with.

>
> - Long term:
> https://issues.jboss.org/browse/ISPN-1413
>
> (***) I still don't fully understand how web apps don't have the same issue as 2LC of not seeing Infinispan classes (Reminder: we're not talking about the contents of the cache, but about the Infinispan classes themselves).

https://github.com/jbossas/jboss-as/blob/master/web/src/main/java/org/jboss/as/web/deployment/JBossContextConfig.java 
appears to be wired to use Paul's ClassLoaderAwareClassResolver.

>
> On Mar 6, 2012, at 8:19 PM, Galder Zamarreño wrote:
>
>>
>> On Mar 6, 2012, at 8:06 PM, David M. Lloyd wrote:
>>
>>> On 03/06/2012 01:02 PM, Galder Zamarreño wrote:
>>>> On Mar 6, 2012, at 6:31 PM, Paul Ferraro wrote:
>>>> </snip>
>>>>> To work around this, we typically store MarshalledValues in the cache - which are marshalled/unmarshalled using a marshalling configuration specific to the application (e.g. via a ModularClassResolver using the ModuleLoader of the deployment unit).
>>>>> https://github.com/jbossas/jboss-as/blob/master/clustering/api/src/main/java/org/jboss/as/clustering/MarshalledValue.java
>>>>> https://github.com/jbossas/jboss-as/blob/master/clustering/api/src/main/java/org/jboss/as/clustering/SimpleMarshalledValue.java
>>>>> https://github.com/jbossas/jboss-as/blob/master/clustering/api/src/main/java/org/jboss/as/clustering/HashableMarshalledValue.java
>>>>
>>>> Isn't a class resolver and a class loader, functionality wise, doing the same thing? I wonder if a custom classloader could not be built that delegates to a ModularClassResolver...
>>>
>>> No, not really.  A class loader loads a class, given a name.  But a
>>> class resolver loads a class given a name *and* stream information.  The
>>> modular class resolver reads the stream information to know which class
>>> loader houses the class in question.  This is critically important
>>> because it's possible (common even) for more than one class to exist in
>>> an AS instance with the same name.  And there is no single class loader
>>> which has visibility to all classes which could potentially be stored in
>>> a cache.
>>>
>>> Yes, accepting a class loader to use is a powerful feature.  However it
>>> *should* just be a convenience abstraction over a more fundamental
>>> feature which allows a class resolver to be set.
>>
>> Thanks for the clarification, makes sense.
>>
>> So, if I understand this correctly, Infinispan should really be enhanced to accept global and per-cache class resolvers, or more globally, as paul suggested below, marshalling configuration instances (or abstractions of them).
>>
>> I think https://issues.jboss.org/browse/ISPN-1367 should be reporpoused to do this.
>>
>>>
>>>>> So, essentially Infinispan itself only ever has to marshal/unmarshal a byte[] wrapper - so the AS has full control over the marshalling process.
>>>>>
>>>>> I would recommend that the 2LC do something similar, and include a mechanism for providing a MarshallingConfiguration per persistence unit.
>>>>
>>>> Possibly…
>>>>
>>>> --
>>>> Galder Zamarreño
>>>> Sr. Software Engineer
>>>> Infinispan, JBoss Cache
>>>>
>>>
>>>
>>> --
>>> - DML
>>> _______________________________________________
>>> infinispan-dev mailing list
>>> infinispan-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>
>> --
>> Galder Zamarreño
>> Sr. Software Engineer
>> Infinispan, JBoss Cache
>>
>>
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>> infinispan-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>
> --
> Galder Zamarreño
> Sr. Software Engineer
> Infinispan, JBoss Cache
>
>
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