[jbosscache-dev] Let's make 3.0 backwards compatible

[Jason T. Greene]

Manik Surtani wrote:
> 
> On 21 Aug 2008, at 09:11, Manik Surtani wrote:
> 
>>>
>>> #1, I don't know how much that screws you up.
>>
>> #1 seems like the cleanest/easiest thing as far as the AS and other 
>> API consumers are concerned, even if it does pollute JBC API.  I plan 
>> to spend a few cycles today revisiting these and seeing what can be 
>> done to maintain compat.  For the most part (Cache, Fqn, CacheFactory) 
>> this should be ok, just would mean having a lot of deprecated methods 
>> around, but for the Eviction and Region interfaces it could be 
>> tricky.  Could mean some sort of internal adapter.
> 
> Ok, I think this is doable.  Unnecessary deprecated crud on most 
> interfaces, but this is ok.  The only *really* messy one is the eviction 
> stuff.  To do this, I have:
> 
> 1.  Reverted interfaces so that EvictionPolicy, EvictionPolicyConfig and 
> EvictionAlgorithm are as they were in 2.x.
> 2.  My new EvictionAlgorithm interface and it's 
> EvictionAlgorithmInterface have been renamed to EvictionSelector and 
> EvictionSelectorConfig - as I should have done from the beginning to 
> prevent confusion
> 3.  Internal eviction logic all use the EvictionSelector and 
> EvictionSelectorConfig interfaces.
> 4.  I have created an EvictionAlgorithmSelectorBridge which implements 
> EvictionSelector, which will be used when a legacy EvictionPolicy is 
> detected.
> 5.  Existing EvictionAlgorithm implementations have now been renamed 
> XXXSelector and implement EvictionSelector
> 6.  The original XXXAlgorithm classes extend the XXXSelector, implement 
> EvictionAlgorithm and are marked as deprecated, and are just here as an 
> extension point.
> 7.  New features, such as EvictionActionPolicies, are not supported by 
> this bridge (naturally!)
> 
> Not checked any of this in as yet, still testing away.  :-)  I ought to 
> be ready to check this in tomorrow, test with AS 5 trunk, etc.
> 

I saw your changes, and reverted my recent POJO Cache changes to restory 
the usage of the 2.x API. I had to make some other changes including:

- Resurrecting JmxUtil (this is needed by PojoCacheJmxWrapper, to know 
where to register CacheJmxWrapper)
- Move InvocationContext from org.jboss.cache.invocation to 
org.jboss.cache (otherwise the 2.x import statements will break)
- Restored generics on Fqn, but with some nice improvements that make 
them useful:

i.e. you can now do stuff like:
Fqn<String> fqn = Fqn.fromString("/a/b/c");
Fqn<Object> fq2 = Fqn.fromRelativeElements(fqn, new Object());

Also, there are still issues with JMX. The wrappers no longer support 
the old format, and some properties have been dropped. Also I need to 
somehow mirror the new JMX API for POJO Cache, although is it ready yet?

-- 
Jason T. Greene
JBoss, a division of Red Hat