RFR: 8356995: Provide default methods min(T, T) and max(T, T) in Comparator interface [v7]

[John R Rose]

On Sun, 3 Aug 2025 13:42:41 GMT, Tagir F. Valeev <tvaleev at openjdk.org> wrote:

>> Implementation of Comparator.min and Comparator.max methods. Preliminary discussion is in this thread:
>> https://mail.openjdk.org/pipermail/core-libs-dev/2025-May/145638.html
>> The specification is mostly composed of Math.min/max and Collections.min/max specifications. 
>> 
>> The methods are quite trivial, so I don't think we need more extensive testing (e.g., using different comparators). But if you have ideas of new useful tests, I'll gladly add them.
>> 
>> I'm not sure whether we should specify exactly the behavior in case if the comparator returns 0. I feel that it could be a useful invariant that `Comparator.min(a, b)` and `Comparator.max(a, b)` always return different argument, partitioning the set of {a, b} objects (even if they are equal). But I'm open to suggestions here.
>
> Tagir F. Valeev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add @implSpec

For users that want the partitioning behavior, just use a reversed argument order, right?


var c = x.min(a,b);
var d = x.min(b,a);
assert c!=d || a==b;

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PR Comment: https://git.openjdk.org/jdk/pull/25297#issuecomment-3165354008