[infinispan-dev] New events to reflect topology change Was: https://issues.jboss.org/browse/ISPN-977

[Mircea Markus]

On 13 May 2011, at 10:28, Manik Surtani wrote:

> So this is related to ISPN-360 which is currently titled "create NodeJoinedEvent".
> 
> Leaving names out for now, essentially, what we need is a notification to inform listeners that (a) a JGroups ViewChange has been detected (b) a rehash has started and (c) a rehash has completed.  Possibly, being more fine-grained, that (d) a new ConsistentHash view has been installed.  Does this cover it all?  If so, how about:
> 
> @ViewChanged (same as we have now)
> @RehashStarted
> @RehashComplete
> @TopologyChanged // to reflect a new CH?
> 
> Thoughts?
Sounds good to me. 
> 
> Cheers
> Manik
> 
> 
> 
> On 11 May 2011, at 13:29, Sanne Grinovero wrote:
> 
>> First thing I thought when reading your email was "OMG do we support
>> on-the-fly hash implementation changes? crazy!"
>> 
>> That's obviously not the case, but if you name it as
>> @ConsistenHashChangeListene that's what I would think.
>> 
>> Wouldn't it be better to change the exact timing of the viewchange
>> event? I don't see why Infinispan users might be more interested in
>> knowing about the topology details according to the transport than
>> what they are about the actual Infinispan hashing topology - I would
>> expect that when I receive which notification the new view is already
>> installed and ready to go; actually I thought that was the case since
>> ever.
>> 
>> What would be the use cases to get the notification *before* the new
>> hash is installed?
>> 
>> Cheers,
>> Sanne
>> 
>> 2011/5/11 Mircea Markus <mircea.markus at jboss.com>:
>>> Hi,
>>> The basic problem behind this is that I need to be notified when a new
>>> consistent hash is installed.
>>> 
>>> ATM there isn't any support (of which I know)  for  a
>>> "@ConsistenHashChangeListener".
>>> 
>>> I'm thinking to add such notifications either:
>>> a) internally: Observer pattern on DistributionManager or even on
>>> DistributionManagerImpl
>>> b) more generically, as a fully flagged listener.
>>> 
>>> I favor a) and then if more people ask for it we will expose it as a fully
>>> flagged listener.
>>> 
>>> Suggestions?
>>> 
>>> Cheers,
>>> Mircea
>>> 
>>> _______________________________________________
>>> infinispan-dev mailing list
>>> infinispan-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>> 
>> 
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> 
> --
> Manik Surtani
> manik at jboss.org
> twitter.com/maniksurtani
> 
> Lead, Infinispan
> http://www.infinispan.org
> 
> 
> 
> 
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