[sakai-core-team] [Building Sakai] Java 8

[Matthew Buckett]

I've made a pull request for removing ConcurrentOrderedMap:

https://github.com/azeckoski/reflectutils/pull/6

But I don't see that this is dependent on getting Sakai to work with Java 8.

On 24 March 2015 at 12:25, Kirschner, Beth <bkirschn at umich.edu> wrote:
> I had the same thoughts about ConcurrentOrderedMap  - I could test and submit a PR that removes this class if Aaron is amenable.
>
> - Beth
>
> On Mar 24, 2015, at 8:04 AM, Matthew Buckett <matthew.buckett at it.ox.ac.uk> wrote:
>
>> On 24 March 2015 at 11:39, Matthew Buckett <matthew.buckett at it.ox.ac.uk> wrote:
>>> I couldn't see any references to ConcurrentOrderedMap in the current
>>> Sakai codebase. The bug with EntityBroker tests failing should be
>>> fixed by:
>>>
>>> https://github.com/azeckoski/reflectutils/commit/4b33c37e8e29f3a260817d9218a5d32e145377aa
>>>
>>> which was a problem with the assumption that the superclass would call
>>> put() when putAll() was called.
>>>
>>> I'd just drop ConcurrentOrderedMap from reflectutils so that people
>>> don't start using it in the future.
>>
>> Looking a little ConcurrentOrderedMap has a few issues:
>> - It loses the performance characteristics of ConcurrentHashMap as it
>> has an internal Vector which limits it's concurrency.
>> - #putIfAbsent(K, V) isn't thread safe. It calls containsKey and then
>> put, but doesn't do it atomically so it's not deterministic.
>> - #remove(key, value) isn't thread safe. It removes the entry from the
>> ConcurrentHashMap and then removes it from the internal Vector without
>> any locking (another thread could be adding in between this).
>>
>> So I'd be even more incline to remove it as it's not really a good
>> implementation of the API and seems like it was just created for
>> completeness.
>>
>> --
>>  Matthew Buckett, VLE Developer, IT Services, University of Oxford
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>



-- 
  Matthew Buckett, VLE Developer, IT Services, University of Oxford