Hi Keith, I think this is one for concurrency interest to answer. Cheers, Martijn On Tue, 17 Sep 2019 at 12:48, Keith Turner <[hidden email]> wrote: The javadoc for ConcurrentHashMap.computeIfAbsent() states the _______________________________________________ Concurrency-interest mailing list [hidden email] http://cs.oswego.edu/mailman/listinfo/concurrency-interest |
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 <[hidden email]> wrote: Hi Keith, _______________________________________________ Concurrency-interest mailing list [hidden email] http://cs.oswego.edu/mailman/listinfo/concurrency-interest |
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 <[hidden email]> wrote:
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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 <[hidden email]> wrote:
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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 <[hidden email]> 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 < >> [hidden email]> 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 <[hidden email]> >>> 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 <[hidden email]> 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 >>>>> >>>> >>> _______________________________________________ >>> Concurrency-interest mailing list >>> [hidden email] >>> http://cs.oswego.edu/mailman/listinfo/concurrency-interest >>> >> Concurrency-interest mailing list [hidden email] http://cs.oswego.edu/mailman/listinfo/concurrency-interest |
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I was wrong and filed On Wed, Sep 18, 2019 at 7:23 AM Keith Turner <[hidden email]> wrote: On Tue, Sep 17, 2019 at 9:35 PM Martin Buchholz <[hidden email]> wrote: _______________________________________________ Concurrency-interest mailing list [hidden email] http://cs.oswego.edu/mailman/listinfo/concurrency-interest |
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