Thanks for the feedback. I agree almost all JDK APIs support offset and
length, so this utility isn’t strictly needed. The library I was working
with at the time may not have been designed to handle that efficiently.
I’ll revisit if a strong use case arises in the future. For now, I’m
withdrawing the proposal.
Kushal
On Sat, 6 Sept, 2025, 7:40 am Peter Burka, <pe...@quux.net> wrote:
> Why do you need to split a large array into equal-sized chunks, and do you
> really want them all allocated at once?
>
> Most (JDK, at least) APIs that take arrays have more flexible versions that
> take an array, a start offset, and a length. With these there's no need to
> copy the array into smaller chunks. You just need the offset/length tuples.
>
> And if you do need smaller chunks, you likely only need them one-by-one.
> Allocating them all at once doubles your memory footprint.
>
> Peter
>
> On Fri, Sep 5, 2025, 9:39 PM Kushal Dixit <kdixit...@gmail.com> wrote:
>
> > ArrayUtils.partition will split arrays into fixed-size chunks.
> > ListUtils.partition can’t be used directly on arrays, and converting
> arrays
> > to lists adds overheads, especially for primitives. This utility will
> work
> > directly on arrays and simplify common tasks.
> >
> > For example, I once had to split a large byte[] into equal-sized chunks
> and
> > realized I wished a ready-made method existed.
> >
> > ArrayUtils.partition will be definitely useful for byte arrays for now.
> I’m
> > not sure about other array types yet.
> >
> > Kushal
> >
> > On Sat, 6 Sept, 2025, 2:44 am sebb, <seb...@gmail.com> wrote:
> >
> > > On Fri, 5 Sept 2025 at 18:46, Kushal Dixit <kdixit...@gmail.com>
> wrote:
> > > >
> > > > Hi All,
> > > >
> > > > I’d like to propose adding a small utility to ArrayUtils for
> > partitioning
> > > > arrays into fixed-size chunks.
> > > >
> > > > Currently, ListUtils.partition exists for lists, but there is no
> direct
> > > > equivalent for arrays in Commons Lang. Developers often write custom
> > > loops
> > > > to achieve the same result.
> > > >
> > > > Proposed API example:
> > > >
> > > > int[][] result = ArrayUtils.partition(new int[]{1, 2, 3, 4, 5}, 2);
> > > > // → [[1, 2], [3, 4], [5]]
> > > >
> > > > Key points:
> > > >
> > > > Supports primitive and object arrays.
> > > >
> > > > Null-safe (returns empty array of arrays if input is null).
> > > >
> > > > Consistent with ListUtils.partition behavior.
> > > >
> > > > Small, general-purpose utility aligned with Lang’s focus on array
> > > helpers.
> > > >
> > > >
> > > > I’d like to check whether the community thinks this addition fits
> > Lang’s
> > > > scope before opening a JIRA/PR.
> > >
> > > What use cases are there for this?
> > >
> > > > Thanks,
> > > > Kushal
> > >
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> > >
> > >
> >
>
