RFR 7065380 : Allow Collections.sort to sort Collections.singletonList() result

[Rémi Forax]

On 03/01/2012 09:52 PM, Vitaly Davidovich wrote:
>
> I thought so too initially but that's optimizing for empty or 
> singleton collections which probably are an edge case? Adding a 
> branch, polymorphic method call, and increasing bytecode size may not 
> be worth it.
>

toArray is also polymorphic, so the typecheck will be done once :)


On 03/01/2012 09:56 PM, Vitaly Davidovich wrote:
>
> Also some collections may not have an O(1) size().
>
> Sent from my phone
>

Yes, you're right. I see now.

Rémi

> Sent from my phone
>
> On Mar 1, 2012 3:25 PM, "Rémi Forax" <forax at univ-mlv.fr 
> <mailto:forax at univ-mlv.fr>> wrote:
>
>     On 03/01/2012 08:50 PM, Mike Duigou wrote:
>
>         Hello all;
>
>         Currently Collections.sort() refuses to sort the lists which
>         result from calling Collections.singletonList(). This makes
>         some sense because the singleton lists are immutable but they
>         are also alway sorted.
>
>         This patch allows Collections.sort() to be used with empty and
>         singleton lists of all types. A short circuit return is
>         provided for lists of length 0 and 1 as they are already sorted.
>
>         WEBREV: http://cr.openjdk.java.net/~mduigou/7065380/0/webrev/
>         <http://cr.openjdk.java.net/%7Emduigou/7065380/0/webrev/>
>
>         For the unit test ignore the diffs and view the "New"
>         file--webrev doesn't understand "hg copy".
>
>         Thanks,
>
>         Mike
>
>
>     Is it not better to check list.size() before calling toArray() ?
>
>     Rémi
>