RFR: 8167002: JAXP schema validator: Use HashSet instead of ArrayList for tracking XML IDs

[Claes Redestad]

On 2016-10-01 18:54, Martin Buchholz wrote:
>
> On Sat, Oct 1, 2016 at 5:45 AM, Claes Redestad
> <claes.redestad at oracle.com <mailto:claes.redestad at oracle.com>> wrote:
>
>
>     On 2016-10-01 02:41, Martin Buchholz wrote:
>
>         https://bugs.openjdk.java.net/browse/JDK-8167002
>         <https://bugs.openjdk.java.net/browse/JDK-8167002>
>         http://cr.openjdk.java.net/~martin/webrevs/openjdk9/xml-id-validation-by-hash/
>         <http://cr.openjdk.java.net/~martin/webrevs/openjdk9/xml-id-validation-by-hash/>
>
>
>     +1, but I have to ask what the intended benefit of writing:
>
>        ((fIds != null) ? fIds : (fIds = new HashSet<>())).add(name);
>
>     rather than keeping the pre-existing pattern:
>
>        if (fIds == null) fIds = new HashSet<>();
>        fIds.add(name);
>
>     If this is about bytecode optimization to help with inlining or such,
>     the latter actually generate a more compact method (14 vs 16 bytecodes).
>
>
> The intent was (by instinct) to not code a re-read of a field, but ...
> yeah .... that wasn't achieved.
> That could be done correctly using
>
>      public void addId(String name) {
>          HashSet<String> x;
>          if ((x = fIds) == null) fIds = x = new HashSet<>();
>          x.add(name);
>      }
>
> but I'll just revert to
>          if (fIds == null) fIds = new HashSet<>();
>          fIds.add(name);
>

Ok, thanks for the explanation!