RFR: 8266571: Sequenced Collections [v2]

[Rémi Forax]

On Tue, 28 Mar 2023 00:01:27 GMT, Stuart Marks <smarks at openjdk.org> wrote:

>> This change is absolutely massive, implementing reversed() basically doubles the number of implementations which means multiple years of debugging / spec fixing.
>> 
>> Reversing a List makes sense, reversing a LinkedHashSet/LinkedHashMap is a nice to have. Having the concept of first and last (getFirst()/getLast()/etc) on Collection is something long awaited. 
>> 
>> I understand that wanting to separate the concept of Collection and SequencedCollection can be conceptually nice, but 
>> multiplying the number of interfaces also multiplies the number of implementations. Pragmatically, this patch is too big compared to how useful it is.
>> 
>> I get that Oracle is rich, but this JEP is not only a burden for Oracle but for the whole community.
>
> @forax 
> 
> Funnily, I was thinking the other day that this change is quite small given that I've been working on it for over two years. :-)
> 
> Anyway, thanks for looking through the implementation.

@stuart-marks, i read your message as not too not far from the sunken cost fallacy.

I still believe that introducing an interface for the concept of sequenced collection makes this change far bigger that it could be. After all, there is no interface for non-null collections, read-only collections, non structurally modifiable collections or sorted collections, so why an interface for ordered collection ?

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PR Comment: https://git.openjdk.org/jdk/pull/7387#issuecomment-1487621122