| 24 |
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*/ |
| 25 |
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|
| 26 |
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package java.util; |
| 27 |
+ |
import java.util.function.Consumer; |
| 28 |
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import java.util.stream.Stream; |
| 28 |
– |
import java.util.Spliterator; |
| 29 |
|
import java.util.stream.Streams; |
| 30 |
– |
import java.util.function.Consumer; |
| 30 |
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|
| 31 |
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/** |
| 32 |
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* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
| 63 |
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* Multiple threads should not access a {@code PriorityQueue} |
| 64 |
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* instance concurrently if any of the threads modifies the queue. |
| 65 |
|
* Instead, use the thread-safe {@link |
| 66 |
< |
* java.util.concurrent.PriorityConsumeringQueue} class. |
| 66 |
> |
* java.util.concurrent.PriorityBlockingQueue} class. |
| 67 |
|
* |
| 68 |
|
* <p>Implementation note: this implementation provides |
| 69 |
|
* O(log(n)) time for the enqueing and dequeing methods |
| 542 |
|
cursor--; |
| 543 |
|
else { |
| 544 |
|
if (forgetMeNot == null) |
| 545 |
< |
forgetMeNot = new ArrayDeque<E>(); |
| 545 |
> |
forgetMeNot = new ArrayDeque<>(); |
| 546 |
|
forgetMeNot.add(moved); |
| 547 |
|
} |
| 548 |
|
} else if (lastRetElt != null) { |
| 783 |
|
heapify(); |
| 784 |
|
} |
| 785 |
|
|
| 786 |
< |
// wrapping constructor in method avoids transient javac problems |
| 787 |
< |
final PriorityQueueSpliterator<E> spliterator(int origin, int fence, |
| 789 |
< |
int expectedModCount) { |
| 790 |
< |
return new PriorityQueueSpliterator<E>(this, origin, fence, |
| 791 |
< |
expectedModCount); |
| 792 |
< |
} |
| 793 |
< |
|
| 794 |
< |
public Stream<E> stream() { |
| 795 |
< |
int flags = Streams.STREAM_IS_SIZED; |
| 796 |
< |
return Streams.stream |
| 797 |
< |
(() -> spliterator(0, size, modCount), flags); |
| 798 |
< |
} |
| 799 |
< |
public Stream<E> parallelStream() { |
| 800 |
< |
int flags = Streams.STREAM_IS_SIZED; |
| 801 |
< |
return Streams.parallelStream |
| 802 |
< |
(() -> spliterator(0, size, modCount), flags); |
| 786 |
> |
public Spliterator<E> spliterator() { |
| 787 |
> |
return new PriorityQueueSpliterator<E>(this, 0, -1, 0); |
| 788 |
|
} |
| 789 |
|
|
| 790 |
< |
/** Index-based split-by-two Spliterator */ |
| 790 |
> |
/** |
| 791 |
> |
* This is very similar to ArrayList Spliterator, except for extra |
| 792 |
> |
* null checks. |
| 793 |
> |
*/ |
| 794 |
|
static final class PriorityQueueSpliterator<E> implements Spliterator<E> { |
| 795 |
|
private final PriorityQueue<E> pq; |
| 796 |
< |
private int index; // current index, modified on advance/split |
| 797 |
< |
private final int fence; // one past last index |
| 798 |
< |
private final int expectedModCount; // for comodification checks |
| 796 |
> |
private int index; // current index, modified on advance/split |
| 797 |
> |
private int fence; // -1 until first use |
| 798 |
> |
private int expectedModCount; // initialized when fence set |
| 799 |
|
|
| 800 |
< |
/** Create new spliterator covering the given range */ |
| 800 |
> |
/** Creates new spliterator covering the given range */ |
| 801 |
|
PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence, |
| 802 |
|
int expectedModCount) { |
| 803 |
< |
this.pq = pq; this.index = origin; this.fence = fence; |
| 803 |
> |
this.pq = pq; |
| 804 |
> |
this.index = origin; |
| 805 |
> |
this.fence = fence; |
| 806 |
|
this.expectedModCount = expectedModCount; |
| 807 |
|
} |
| 808 |
|
|
| 809 |
< |
public PriorityQueueSpliterator<E> trySplit() { |
| 810 |
< |
int lo = index, mid = (lo + fence) >>> 1; |
| 809 |
> |
private int getFence() { // initialize fence to size on first use |
| 810 |
> |
int hi; |
| 811 |
> |
if ((hi = fence) < 0) { |
| 812 |
> |
expectedModCount = pq.modCount; |
| 813 |
> |
hi = fence = pq.size; |
| 814 |
> |
} |
| 815 |
> |
return hi; |
| 816 |
> |
} |
| 817 |
> |
|
| 818 |
> |
public Spliterator<E> trySplit() { |
| 819 |
> |
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
| 820 |
|
return (lo >= mid) ? null : |
| 821 |
|
new PriorityQueueSpliterator<E>(pq, lo, index = mid, |
| 822 |
|
expectedModCount); |
| 823 |
|
} |
| 824 |
|
|
| 825 |
< |
public void forEach(Consumer<? super E> block) { |
| 826 |
< |
Object[] a; int i, hi; // hoist accesses and checks from loop |
| 827 |
< |
if (block == null) |
| 825 |
> |
@SuppressWarnings("unchecked") |
| 826 |
> |
public void forEachRemaining(Consumer<? super E> action) { |
| 827 |
> |
int i, hi, mc; // hoist accesses and checks from loop |
| 828 |
> |
PriorityQueue<E> q; Object[] a; |
| 829 |
> |
if (action == null) |
| 830 |
|
throw new NullPointerException(); |
| 831 |
< |
if ((a = pq.queue).length >= (hi = fence) && |
| 832 |
< |
(i = index) >= 0 && i < hi) { |
| 833 |
< |
index = hi; |
| 834 |
< |
do { |
| 835 |
< |
@SuppressWarnings("unchecked") E e = (E) a[i]; |
| 836 |
< |
block.accept(e); |
| 837 |
< |
} while (++i < hi); |
| 838 |
< |
if (pq.modCount != expectedModCount) |
| 839 |
< |
throw new ConcurrentModificationException(); |
| 831 |
> |
if ((q = pq) != null && (a = q.queue) != null) { |
| 832 |
> |
if ((hi = fence) < 0) { |
| 833 |
> |
mc = q.modCount; |
| 834 |
> |
hi = q.size; |
| 835 |
> |
} |
| 836 |
> |
else |
| 837 |
> |
mc = expectedModCount; |
| 838 |
> |
if ((i = index) >= 0 && (index = hi) <= a.length) { |
| 839 |
> |
for (E e;; ++i) { |
| 840 |
> |
if (i < hi) { |
| 841 |
> |
if ((e = (E) a[i]) == null) // must be CME |
| 842 |
> |
break; |
| 843 |
> |
action.accept(e); |
| 844 |
> |
} |
| 845 |
> |
else if (q.modCount != mc) |
| 846 |
> |
break; |
| 847 |
> |
else |
| 848 |
> |
return; |
| 849 |
> |
} |
| 850 |
> |
} |
| 851 |
|
} |
| 852 |
+ |
throw new ConcurrentModificationException(); |
| 853 |
|
} |
| 854 |
|
|
| 855 |
< |
public boolean tryAdvance(Consumer<? super E> block) { |
| 856 |
< |
if (index >= 0 && index < fence) { |
| 857 |
< |
@SuppressWarnings("unchecked") E e = |
| 858 |
< |
(E)pq.queue[index++]; |
| 859 |
< |
block.accept(e); |
| 855 |
> |
public boolean tryAdvance(Consumer<? super E> action) { |
| 856 |
> |
int hi = getFence(), lo = index; |
| 857 |
> |
if (lo >= 0 && lo < hi) { |
| 858 |
> |
index = lo + 1; |
| 859 |
> |
@SuppressWarnings("unchecked") E e = (E)pq.queue[lo]; |
| 860 |
> |
if (e == null) |
| 861 |
> |
throw new ConcurrentModificationException(); |
| 862 |
> |
action.accept(e); |
| 863 |
|
if (pq.modCount != expectedModCount) |
| 864 |
|
throw new ConcurrentModificationException(); |
| 865 |
|
return true; |
| 867 |
|
return false; |
| 868 |
|
} |
| 869 |
|
|
| 870 |
< |
public long estimateSize() { return (long)(fence - index); } |
| 871 |
< |
public boolean hasExactSize() { return true; } |
| 872 |
< |
public boolean hasExactSplits() { return true; } |
| 870 |
> |
public long estimateSize() { |
| 871 |
> |
return (long) (getFence() - index); |
| 872 |
> |
} |
| 873 |
> |
|
| 874 |
> |
public int characteristics() { |
| 875 |
> |
return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL; |
| 876 |
> |
} |
| 877 |
|
} |
| 878 |
|
} |
