> The problem is that everyone will have to pay for the extra storage cost for
maintaining insertion order. Even if people don't need it.
I understand that.
The main point of my message is that I think it is worth the cost, that a fixed
iteration order should be the default, and that it should be considered to be a
niche use case to prioritize the memory savings of a random iteration order.
This use case should be catered to by third-party libraries or alternative
API:s.
These are a summary of the arguments (which I failed to provide in my original
message):
* Many, probably most, uses of maps in Java benefit from a fixed iteration
order.
* It is easy to get bugs or confusing behaviour by mistake when random
iteration order is the default.
* The memory cost of an insertion-based iteration order is not very high.
* The Guava developers, and, as Remi notes, the Python developers, have also
drawn this conclusion. (Argument from authority.)
Best regard,
Jens Lideström
On 2023-03-26 12:48, Kasper Nielsen wrote:
On Sun, 26 Mar 2023 at 10:38, Jens Lideström <j...@lidestrom.se> wrote:
I think Map#of and friends would be more useful and less error prone if they
where to return collections that have a fixed iteration order, where the order
is defined by the insertion order when the map is created.
The problem is that everyone will have to pay for the extra storage cost for
maintaining insertion order. Even if people don't need it. Hence, why I
suggested adding factory/copyOf methods for SequencedMap/SequencedSet
for those people that need to rely on order. (Rereading Chris's email I know it
wouldn't help his use-case).
/Kasper
