RFR 8020061: Clarify reporting characteristics between splits

[Paul Sandoz]

On Oct 8, 2013, at 3:02 PM, Chris Hegarty <chris.hegarty at oracle.com> wrote:

> Sorry Paul, I know the apiNote says "for examples see ..." but would you mind providing an example. I'm scratching my head.
> 

     * @apiNote Most Spliterators for Collections, that cover all elements of a
     * {@code Collection} report this characteristic. Sub-spliterators, such as
     * those for {@link HashSet}, that cover a sub-set of elements and
     * approximate their reported size do not.
     */
    public static final int SIZED      = 0x00000040;

        Set<Integer> s = new HashSet<>(Arrays.asList(1, 2, 3, 4));

        Spliterator<Integer> split1 = s.spliterator();
        System.out.println(split1.hasCharacteristics(Spliterator.SIZED));

        Spliterator<Integer> split2 = split1.trySplit();
        System.out.println(split1.hasCharacteristics(Spliterator.SIZED));
        System.out.println(split2.hasCharacteristics(Spliterator.SIZED));

Paul.


> -Chris.
> 
> On 10/08/2013 12:42 PM, Paul Sandoz wrote:
>> Hi,
>> 
>> The following patch is a minor clarification to the documentation of Spliterator.characteristics():
>> 
>>   http://hg.openjdk.java.net/lambda/lambda/jdk/rev/653d17f35169
>> 
>> Paul.
>> 
>> --- a/src/share/classes/java/util/Spliterator.java	Tue Oct 01 12:10:04 2013 +0200
>> +++ b/src/share/classes/java/util/Spliterator.java	Tue Oct 08 13:36:27 2013 +0200
>> @@ -414,12 +414,18 @@ public interface Spliterator<T> {
>>       * #ORDERED}, {@link #DISTINCT}, {@link #SORTED}, {@link #SIZED},
>>       * {@link #NONNULL}, {@link #IMMUTABLE}, {@link #CONCURRENT},
>>       * {@link #SUBSIZED}.  Repeated calls to {@code characteristics()} on
>> -     * a given spliterator should always return the same result.
>> +     * a given spliterator, prior to or in-between calls to {@code trySplit},
>> +     * should always return the same result.
>>       *
>>       * <p>If a Spliterator reports an inconsistent set of
>>       * characteristics (either those returned from a single invocation
>>       * or across multiple invocations), no guarantees can be made
>>       * about any computation using this Spliterator.
>> +     *
>> +     * @apiNote The characteristics of a given spliterator before splitting
>> +     * may differ from the characteristics after splitting.  For specific
>> +     * examples see the characteristic values {@link #SIZED}, {@link #SUBSIZED}
>> +     * and {@link #CONCURRENT}.
>>       *
>>       * @return a representation of characteristics
>>       */
>>