RFR 8003981: Support Parallel Array Sorting - JEP 103
chris.hegarty at oracle.com
Thu Dec 20 17:31:06 UTC 2012
This is a review request for the addition of utility methods to
java.util.Arrays that provide sorting of arrays in parallel, JEP 103 .
Current sorting implementations provided by the Java Collections
Framework (Collections.sort and Arrays.sort) all perform the sorting
operation sequentially in the calling thread. This enhancement will
offer the same set of sorting operations currently provided by the
Arrays class, but with a parallel implementation that utilizes the
Fork/Join framework. These new API’s are still synchronous with regard
to the calling thread as it will not proceed past the sorting operation
until the parallel sort is complete.
The actual sorting API this proposal adds will leverage the
ForkJoinPool.commonPool (default Fork/Join pool defined as part of JEP
155). The sorting algorithm is that used in Doug Lea’s ParallelArray
This work was originally done over in the lambda/lambda repo by David
Holmes, and is now being cleaned up and brought into jdk8.
Open issues/differences from version in lambda:
1) Is is necessary for MIN_ARRAY_SORT_GRAN to be in the public API?
It is an implementation detail (easy to remove).
2) The use of FJP.commonPool is an implementation detail, not
part of the spec. Should not be a problem, just worth pointing
out, as it differs from what is in lambda/lambda.
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