[infinispan-dev] QueryIterator inconsistencies

[Manik Surtani]

On 25 Sep 2012, at 15:00, Sanne Grinovero <sanne at infinispan.org> wrote:

> On 25 September 2012 12:11, Marko Lukša <marko.luksa at gmail.com> wrote:
>> On 25.9.2012 11:51, Sanne Grinovero wrote:
>>>>>> Any comments / other ideas?
>>>>>> 
>>>>>> Marko
>>>>> That's a lot of changes needed. One would say we could deprecate all
>>>>> methods and rewrite the new ones, but wouldn't it be better to
>>>>> deprecate the interface and introduce a brand new one?
>>>>> What about "ResultsIterator" ? after all, we're not iterating on queries..
>>>> I agree. The only thing that bothers me is that CacheQuery would then
>>>> need new methods called (lazy)resultIterator() (instead of iterator(),
>>>> which already exists).
>>> Right. though I like "resultIterator()" more so we're having luck in
>>> this case ;)
>>> 
>>> Any better suggestion for names? Anyone thinks it's worth to remove
>>> the old ones without a deprecation step to reuse the old names?
>>> 
>> One thing to keep in mind is that CacheQuery extends Iterable, therefore
>> a lot of users will actually implicitly invoke the iterator() method.
>> This pretty much means we should not introduce resultIterator().
> 
> Looks like we have to break backwards compatibility. From the look of
> how this API was, I guess not many users dealt with it before you, so
> I'm fine with that, I don't see how else we can fix this API.
> 
> While at it, it would be nice to see if we can change the signature
> from "extends Iterable<Object>" to return an iterator on the types
> compatible with the values of the cache, since the Cache supports
> proper generics.
> 
> To deal safely with Iterable, I think it would be better to default to
> lazy loading mode and to provide an overloaded method which allows to
> specify a loading mode.
> 
> Anyone having a better idea which allows to not break backwards compatibility?

Not really - I think compatibility will break, sadly.  :/

One option to maintain compatibility is to keep the existing QueryIterator and mark it as deprecated, and write a new iterator, maybe call it a ResultIterator (which is more accurate anyway!).

--
Manik Surtani
manik at jboss.org
twitter.com/maniksurtani

Platform Architect, JBoss Data Grid
http://red.ht/data-grid

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