Re: Concurrent Hash Map javadoc question

Please drop the discuss@openjdk list from this exchange - thanks.

David

On 18/09/2019 12:19 pm, Martin Buchholz wrote:
> How about
> The entire method invocation is performed atomically, so the function is
> applied at most once per key.
> =>
> The entire method invocation is performed atomically.  The function is
> applied at most once per key.
> 
> On Tue, Sep 17, 2019 at 7:08 PM Benjamin Manes <[email protected]> wrote:
> 
>> All three state that "The entire method invocation is performed
>> atomically" and computeIfAbsent merely explains this with the addition "so
>> the function is applied at most once per key." Since all computations are
>> atomic operations in ConcurrentHashMap, this seems to be implied in the
>> other cases rather than explicitly clarified.
>>
>> On Tue, Sep 17, 2019 at 6:36 PM Martin Buchholz via Concurrency-interest <
>> [email protected]> wrote:
>>
>>> I think this doc difference is intentional.
>>>
>>> In case of a retry loop, the value may have changed in the case of
>>> computeIfPresent or compute and so the function must be called again with
>>> the new value.
>>>
>>> On Tue, Sep 17, 2019 at 4:36 PM Martijn Verburg <[email protected]>
>>> wrote:
>>>
>>>> Hi Keith,
>>>>
>>>> I think this is one for concurrency interest to answer.
>>>>
>>>> Cheers,
>>>> Martijn
>>>>
>>>>
>>>> On Tue, 17 Sep 2019 at 12:48, Keith Turner <[email protected]> wrote:
>>>>
>>>>> The javadoc for ConcurrentHashMap.computeIfAbsent() states the
>>>>> remapping function is applied at most once.  The functions
>>>>> computeIfPresent() and compute() do not explicitly state if the
>>>>> remapping functions could possibly be run multiple times. Does anyone
>>>>> know if computeIfPresent() and compute() are guaranteed to only run
>>>>> the remapping functions at most once?  If so, should the javadoc be
>>>>> updated?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Keith
>>>>>
>>>>
>>> _______________________________________________
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>>>
>>
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