[infinispan-dev] Hot Rod Remote Events #3: Customizing events

[Emmanuel Bernard]

On 23 sept. 2014, at 09:15, Radim Vansa <rvansa at redhat.com> wrote:

>>> Please, consider also the corner cases such as overwriting already updated
>>> value, e.g. after OutdatedTopologyException. Sometimes the oldValue might
>>> not be correct (we probably can't evade this but I hope we can detect that
>>> it might have happened) and the Converter should react to that - e.g. by
>>> sending full new value instead of empty diff (because oldValue == newValue).
>> Unfortunately it is too late to retrieve the old value by the time we
>> do the retry if it was already replicated to a backup owner.  We do
>> detect this and provide that info the Listener event, but talking with
>> some others I am unsure if providing this information to the
>> Filter/Converter is fully needed.
> 
> Not providing that info to Converter limits the use-case of converter 
> producing deltas. In fact it's even worse - users will write that 
> converter (because the won't expect incorrect old values - nobody reads 
> documentation) and it will give them unreliable results.

Would passing an enum representing the transition - in this case the error state - be sufficient?