[infinispan-dev] Feedback and requests on clustered and remote listeners

[William Burns]

On Tue, Sep 23, 2014 at 9:31 AM, Mircea Markus <mmarkus at redhat.com> wrote:
>
> On Sep 23, 2014, at 16:27, Emmanuel Bernard <emmanuel at hibernate.org> wrote:
>
>>
>> On 23 Sep 2014, at 14:53, Mircea Markus <mmarkus at redhat.com> wrote:
>>
>>> On Sep 23, 2014, at 15:18, Emmanuel Bernard <emmanuel at hibernate.org> wrote:
>>>
>>>>> I am not sold on this as it seems pretty trivial to decipher which
>>>>> operation is which and the information would be present on the
>>>>> javadocs as well.
>>>>
>>>> I very strongly disagree. Cf the other thread with Radim 's comment on topology error.
>>>> And think about *future* evolutions. The enum would make that much safer. In the bin enum world you would have to introduce a new YetAnotherKeyValueFilter interface :)
>>>
>>> Nicer than an enum would be an explicit method, e.g. handlePut/handleDelete/handleCreate/handleUpdate, as these would also receive the appropriate param list. Of course this means moving away from the KeyValueFilter to an UpdateFilter (good name, Radim) used only for cluster listeners.

I like the name as well :)  The only thing that I dislike about the
extra methods is the fact that it isn't a Functional interface, which
would be nice to have when we ever move to Java 8, but that may be
thinking too far into the future :P

>>> Will, what would be the overall impact on the A

The biggest part is the usage with the cluster iterator.  Currently
the Listener uses the same filter that it is provided to also do the
iteration.  If we want to go down the line of having the extra
interface(s), which overall I do like, then I am thinking we may want
to change the Listener annotation to no longer have an
includeCurrentState parameter and instead add a new method to the
addListener method of Cache that takes a KeyValueFilter and the new
UpdateFilter (as well as the 2 converters).  I can then add in 2
bridge implementations so that you don't have to implement the other
if your implementation can handle both types.  Also from the other
post it seems that I should add the retry boolean to all the
appropriate methods so that you can have a chance to detect if an
update was missed.  Unless this seems to cumbersome?

>>
>> If you do that you must also provide an abstract class with default noop operations that filter implementations would extend. Otherwise you are back with backward compatibility problems.
>
> KeyValueFilter was introduced in 7.0, or other backward compatibility problem you have in mind?

I believe Emmanuel is referring to if we added additional operations
to the filter, but I am not sure what other operations we would want
to add to it.  If anything we would probably make a different type of
filter specific to its use case.

>
> Cheers,
> --
> Mircea Markus
> Infinispan lead (www.infinispan.org)
>
>
>
>
>
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