JDK 9 RFR of JDK-8146668: Replace custom check/range functionality with check index/range methods in java.util.Objects

[Amy Lu]

Thank you Paul and Martin for your review.

On 1/13/17 12:52 AM, Paul Sandoz wrote:
> HI Amy,
>
> Overall this looks very good, well done.
>
>
> At this point we are down to two things:
>
> 1) should we preserve exception messages?
>
> 2) due diligence on the performance.
>
>
> On 1) my preference is that uniform (and informative) messages are better for IndexOutOfBounds and subtypes, and defining that in addition to the checks in one place is very valuable. In some sense that does change some behavioural compatibility and i think because of that pushing in 10 (when the repos) open with a CCC would be more preferable.
Got it. Will wait for 10.
>
> On 2) this is a valuable exercise to perform (either using an existing test and/or writing JMH benchmarks). I don’t expect any major problems. Care was taken to ensure the uncommon exception processing path will optimize away for the common case. The BiFunction parameter passed as the last argument is always a constant, so should fold away from the hot path.

Tested with java/util/ArrayList/RangeCheckMicroBenchmark.java and 
java/nio/Buffer/SwapMicroBenchmark.java, no performance regression observed.

java/util/ArrayList/RangeCheckMicroBenchmark.java

without 8146668
--------------------
  get                             26          1
  set                             40.6        1.5707
  get/set                         85.7        3.3002
  add/remove at end               337.5       12.9197
  subList get                     25          0.9747
  subList set                     59.9        2.3
  subList get/set                 92.2        3.5414
  subList add/remove at end       429.8       16.45

with 8146668
--------------------
  get                             26          1
  set                             39.1        1.5188
  get/set                         86.8        3.3363
  add/remove at end               335.5       12.8549
  subList get                     24.8        0.9715
  subList set                     59.2        2.2728
  subList get/set                 92.2        3.5473
  subList add/remove at end       427.7       16.3789

java/nio/Buffer/SwapMicroBenchmark.java

without 8146668
--------------------
  swap char LITTLE_ENDIAN         11          1
  swap short LITTLE_ENDIAN        10.2        0.9895
  swap int LITTLE_ENDIAN          5           0.4961
  swap long LITTLE_ENDIAN         3           0.3345

with 8146668
--------------------
  swap char LITTLE_ENDIAN         10.1        1
  swap short LITTLE_ENDIAN        10.1        0.9995
  swap int LITTLE_ENDIAN          5           0.5005
  swap long LITTLE_ENDIAN         3           0.3327

Thanks,
Amy
>
> Paul.
>
>
>> On 11 Jan 2017, at 18:10, Amy Lu <amy.lu at oracle.com> wrote:
>>
>> 8135248 and 8155794 introduced utility methods for checking indexes and ranges. Existing code with custom checkIndex/checkRange can be updated to use these methods. Please review the patch for this purpose:
>>
>> bug: https://bugs.openjdk.java.net/browse/JDK-8146668
>> webrev: http://cr.openjdk.java.net/~amlu/8146668/webrev.01
>>
>> The type of exception thrown are preserved. Custom checkIndex/checkRange functions that throw IOOBE are now using ‘check’ utility methods provided by java.lang.Objects (which also throws IOOBE), functions that throw other exceptions use jdk.internal.util.Preconditions to preserve exception types, with the help of new BiFunction vars.
>>
>> I'd like to get this in JDK 9 if it's not too late, otherwise, JDK 10.
>>
>> Thanks,
>> Amy