Re: [infinispan-dev] [Pull Request] Modular Classloading Compatibility
On Wed, May 4, 2011 at 7:18 AM, "이희승 (Trustin Lee)" <trustin(a)gmail.com>
wrote:
On 05/03/2011 09:33 PM, Sanne Grinovero wrote:
> 2011/5/3 "이희승 (Trustin Lee)" <trustin(a)gmail.com>:
>> On 05/03/2011 05:08 AM, Sanne Grinovero wrote:
>>> 2011/5/2 Manik Surtani <manik(a)jboss.org>:
>>>>
>>>> On 1 May 2011, at 13:38, Pete Muir wrote:
>>>>
>>>>>>> As in, user API? That's a little intrusive... e.g.,
put(K, V, cl) ?
>>>>>>
>>>>>> Not for put, since you have the class, just get, and I was
thinking
>>>>>> something more like:
>>>>>>
>>>>>> Foo foo = getUsing(key, Foo.class)
>>>>>
>>>>> This would be a pretty useful addition to the API anyway to avoid
user casts.
>>>>
>>>> Maybe as an "advanced" API, so as not to pollute the basic API?
A bit like:
>>>>
>>>> Foo f = cache.getAdvancedCache().asClass(Foo.class).get(key);
>>>
>>> doesn't look much better than a cast, but is more cryptical :)
>>>
>>> getting back to the classloader issue, what about:
>>>
>>> Cache c = cacheManager.getCache( cacheName, classLoader );
>>>
>>> or
>>> Cache c = cacheManager.getCache( cacheName ).usingClassLoader(classLoader );
>>>
>>> BTW if that's an issue on the API, maybe you should propose it to
>>> JSR-107 as well ?
>>
>> We have a configurable Marshaller, right? Then why don't we just use
>> the class loader that the current Marshaller uses?
>
> +1
> I like the clean approach, not sure how you configure the "current
> Marshaller" to use the correct CL ?
> Likely hard to do via configuration file :)
By default, we could use the class loader that the current Unmarshaller
uses, and let user choose a class loader for a certain get() call.
So, we need to deal with the two issues here:
1) Make sure that user can configure the default class loader in runtime
and calling get() (and consequently related unmarshaller) will use the
default class loader:
cache.setDefaultClassLoader(UserClass.class.getClassLoader())
2) Provide an additional API that allows a user to specify a class
loader for the current transaction or context:
cache.get(K key, Class<V> clazz) // +1 to Pete's suggestion
If V is Set<MyObject> then Set<MyObject>.class.getClassLoader() will
give you the system classloader, which in most cases won't be able the
MyObject class. It may not even be a Set<MyObject> of course, it could
be just Set<?>.
We could have a "shortcut" so the users can pass in a class instead of
a classloader to avoid writing ".getClassLoader()", but we shouldn't
require any relation between the class passed in and the class of the
return value.
Dan