Bag (Multiset) Collection

[Holo The Sage Wolf]

By "ordered collection" you mean "unordered collection"?

How common is it to actually use a multiset in general? Of course there are
use cases, and there are areas in which it is used a lot, but I don't
believe it is common enough to be part of the std with the one exception of
concurrent bag.

On Sat, 20 Apr 2024, 23:25 ІП-24 Олександр Ротань, <rotan.olexandr at gmail.com>
wrote:

> In this letter I would like to express some of my thoughts regarding the
> potential Multiset interface.
>
> I, personally, have encountered a few situations where such an interface
> could come in handy, mostly when I needed an ordered collection that
> permits duplicates. That time I used guava`s TreeMultiset, but I think Java
> itself should have such a collection in its std library. While it is not a
> very common problem, there are still a bunch of use cases where such things
> could come in handy.
>
> I am willing to take on development of such thing, but there are a few
> concerns about Multiset:
>
> 1. Is there any other use for this besides ordered collection that permits
> duplicates? I can't remember anything else from the top of my head.
>
> 2. Guava's TreeMultiset class hierarchy pretty much imitates TreeSet class
> hierarchy, while not being directly connected. I think introducing any
> other ordered collection will require some refactoring of existing
> collection interfaces (for example extract SortedCollection from SortedSet,
> Navigable Collection from NavigableSet etc.). From the perspective of clean
> code, this would be the right decision, but I feel like this will be a very
> complex task to accomplish.
>
> 3. Maybe there should be few versions of Tree collection (for example, for
> regular tasks red-black tree and B-Tree for large amounts of data). I have
> some expirience implementing both, but is it really needed in standard
> library?
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/core-libs-dev/attachments/20240420/001d5826/attachment.htm>