> On May 9, 2018, at 11:17 AM, Martin Buchholz <[email protected]> wrote:
>
> Time to do this, since Claes is also touching ArrayList.
>
> http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/overview.html
>
> <http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/overview.html>
>
> 8202685: Improve ArrayList replaceAll
> http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/replaceAll/index.html
>
> <http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/replaceAll/index.html>
> https://bugs.openjdk.java.net/browse/JDK-8202685
> <https://bugs.openjdk.java.net/browse/JDK-8202685>
>
ArrayList.java
—
@Override
public void replaceAll(UnaryOperator<E> operator) {
Objects.requireNonNull(operator);
final int expectedModCount = modCount;
final Object[] es = elementData;
! final int size = this.size;
! for (int i = 0; modCount == expectedModCount && i < size; i++)
es[i] = operator.apply(elementAt(es, i));
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
- modCount++;
}
A CME is not necessarily associated with just structural modifications it
could, on a best effort basis, be associated with any modification, which is
cheaper to do for bulk operations rather than individual operations, and this
operation can be used to perturb all the elements of the list (just like sort)
causing strange and hard to track bugs while in the middle of iterating. IMHO
its better to fail under such circumstances rather than be silent.
> 8201386: Miscellaneous changes imported from jsr166 CVS 2018-05
> http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/miscellaneous/index.html
>
> <http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/miscellaneous/index.html>
> https://bugs.openjdk.java.net/browse/JDK-8201386
> <https://bugs.openjdk.java.net/browse/JDK-8201386>
>
PriorityQueue
—
587 public E poll() {
588 final Object[] es;
589 final E result;
590
591 if ((result = (E) ((es = queue)[0])) != null) {
592 modCount++;
593 final int n;
594 final E x = (E) es[(n = --size)];
595 es[n] = null;
596 if (n > 0) {
597 final Comparator<? super E> cmp;
598 if ((cmp = comparator) == null)
599 siftDownComparable(0, x, es, n);
600 else
601 siftDownUsingComparator(0, x, es, n, cmp);
602 }
603 }
604 return result;
605 }
Why inline the siftDown method?
Paul.
