[infinispan-dev] [hibernate-dev] [ISPN-6] (Infinispan cache provider for Hibernate) Remaining TODOs, notes and questions

[Manik Surtani]

On 11 Aug 2009, at 16:34, Galder Zamarreno wrote:

>
>
> On 08/10/2009 01:09 PM, Galder Zamarreno wrote:
>>
>> On 08/10/2009 12:42 PM, Manik Surtani wrote:
>
> </snip>
>
>>> Well, I think we need both.
>>>
>>> getConfiguration(String name) to retrieve a configuration template  
>>> and
>>> modify it.
>>> defineCache(String newName, String templateName, Configuration
>>> overrides) to create a new configuration based on an existing one.  
>>> Maybe
>>> this name should change to something more intuitive? Perhaps  
>>> instead of
>>> defineCache, we have:
>>>
>>> Configuration defineConfiguration(String configurationName,
>>> Configuration overrides) // registers and names a NEW configuration,
>>> based on the default cfg and the overrides passed in
>>>
>>> Configuration defineConfiguration(String configurationName, String
>>> templateName, Configuration overrides) // registers and names a NEW
>>> configuration, based on an existing, predefined configuration and  
>>> the
>>> overrides passed in
>>>
>>> WDYT?
>>
>> That would be a great way to combine the two API requirements. I  
>> assume
>> that the returned Configuration instances returned would have had the
>> overrides applied to them already.
>>
>> Let me work on this APIs in parallel to the work I'm doing for  
>> ISPN-6 so
>> that I can fully exercise/test and see if there's anything we'd  
>> need to
>> change.
>>
>> https://jira.jboss.org/jira/browse/ISPN-152
>
> A quick update on this. I have implemented ISPN-152, integrated it  
> with the cache provider and the tests I have are now passing. Just a  
> heads up on a change of behaviour.
>
> defineConfiguration(*) methods do no longer throw  
> DuplicateCacheNameException since this limits the API a lot  
> disabling any type of configuration redefininitions/overriding.  
> Example:
>
> defineConfiguration("entity", "entity", overrides);
>
> This means, take the configuration for named cache "entity", apply  
> overrides and use that as new "entity" cache name configuration. If  
> we're throwing DuplicateCacheNameException(s), we wouldn't be able  
> to do this and this seems like a valid use case to me.
>
> By the way, I've already noted this in the javadoc but doing the  
> following:
>
> Configuration c = defineConfiguration("entity", new Configuration());
>
> is a way to return "entity" named cache's configuration! (equivalent  
> to doing something like: manager.getConfiguration("entity") if such  
> method existed!) IOW, this defineConfiguration method is saying:  
> "define a configuration, based on "entity" and apply no overrides  
> (cos no setters have been called in the Configuration instance!) and  
> return new configuration instance"
>
> I've detailed all this in CacheManager's javadoc that you can find  
> attached. If you get the chance, have a read to it and let me know  
> if anything is not clear enough.

Most of it sounds good, but the javadoc on defineConfiguration() is a  
bit misleading.

"  * <p/>
     * If cache name hasn't been defined before, this method creates a  
clone of the configuration of the cache whose
     * name matches the given template cache name, then applies the  
configuration overrides passed and returns this
     * configuration instance.
     * <p/>
     * If cache name has been previously defined, this method creates  
a clone of this cache's existing configuration,
     * applies the overrides and return this configuration instance.
     * <p/>"

The first bit makes sense.  The second bit though, I would expect the  
behaviour to be to clone the template cfg, apply changes, and  
overwrite the existing named config rather than use the existing named  
config as the template (rather than templateCacheName).

Cheers
--
Manik Surtani
manik at jboss.org
Lead, Infinispan
Lead, JBoss Cache
http://www.infinispan.org
http://www.jbosscache.org