RFR: 8314502: Change the comparator taking version of GrowableArray::find to be a template method

[Johan Sjölen]

On Fri, 25 Aug 2023 08:55:29 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> It's arbitrary and chosen by the caller through `f`, so I can't say :-). The best use case we have now is when you only have an `int` which uniquely describes an `LGRPSpace`.
>
> This code looks similar to a capturing lambda. Would an alternative be to use that instead and let the calling code be changed to:
> 
> 
>   int i = lgrp_spaces()->find([](LGRPSpace* space) {
>     return space->lgrp_id() == lgrp_id;
>   });
> 
> 
> Alternatively:
> 
>   auto matches_lgrp_id = [](LGRPSpace* space) {
>     return space->lgrp_id() == lgrp_id;
>   };
>   
>   int i = lgrp_spaces()->find(matches_lgrp_id);

We could just as well do a capturing lambda here, yes. Then we'd have:

```c++
template<F>
int find(F finder);


It'd be a template instead of function pointer since it's a capturing lambda and  `std::function` is not permitted in Hotspot AFAIK. 

As an aside, to clarify for readers: There's a `&` missing in the capture list of your examples.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15418#discussion_r1305442361