Optimize (Linked-)HashMap lookup when backing array is null

[Roger Riggs]

Hi,

How does the performance degrade when the computation of the hash
is non-trivial. For example, with an array as a key or an object with 
fields that are objects?
The original code made a point of computing the hash only once.

??, Roger


On 5/19/20 3:21 PM, Claes Redestad wrote:
> Thanks for producing the simpler variant and getting some comparative
> runs done.
>
> On 2020-05-19 19:50, Christoph Dreis wrote:
>> I would probably go for the first version although it is a bit more 
>> complicated and has the computeIfPresent caveat, because it doesn't 
>> slow down the common Map.get() case when the map is actually filled.
>
> It is a bit of step up in complexity, but getting the win without adding
> a branch to Map.get() _is_ a nice property.
>
>>
>> Let me know what you think.
>
> If core libs maintainers are fine with the added complexity of your
> original patch, I think it looks ok.
>
> /Claes