24 |
|
*/ |
25 |
|
|
26 |
|
package java.util; |
27 |
+ |
import java.util.function.Consumer; |
28 |
|
import java.util.stream.Stream; |
28 |
– |
import java.util.Spliterator; |
29 |
|
import java.util.stream.Streams; |
30 |
– |
import java.util.function.Block; |
30 |
|
|
31 |
|
/** |
32 |
|
* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
59 |
|
* the priority queue in any particular order. If you need ordered |
60 |
|
* traversal, consider using {@code Arrays.sort(pq.toArray())}. |
61 |
|
* |
62 |
< |
* <p> <strong>Note that this implementation is not synchronized.</strong> |
62 |
> |
* <p><strong>Note that this implementation is not synchronized.</strong> |
63 |
|
* Multiple threads should not access a {@code PriorityQueue} |
64 |
|
* instance concurrently if any of the threads modifies the queue. |
65 |
|
* Instead, use the thread-safe {@link |
450 |
|
* this queue |
451 |
|
* @throws NullPointerException if the specified array is null |
452 |
|
*/ |
453 |
+ |
@SuppressWarnings("unchecked") |
454 |
|
public <T> T[] toArray(T[] a) { |
455 |
+ |
final int size = this.size; |
456 |
|
if (a.length < size) |
457 |
|
// Make a new array of a's runtime type, but my contents: |
458 |
|
return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
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, |
787 |
< |
int expectedModCount) { |
788 |
< |
return new PriorityQueueSpliterator(this, origin, fence, |
789 |
< |
expectedModCount); |
786 |
> |
final Spliterator<E> spliterator() { |
787 |
> |
return new PriorityQueueSpliterator<E>(this, 0, -1, 0); |
788 |
|
} |
789 |
|
|
790 |
|
public Stream<E> stream() { |
791 |
< |
int flags = Streams.STREAM_IS_SIZED; |
794 |
< |
return Streams.stream |
795 |
< |
(() -> spliterator(0, size, modCount), flags); |
791 |
> |
return Streams.stream(spliterator()); |
792 |
|
} |
793 |
+ |
|
794 |
|
public Stream<E> parallelStream() { |
795 |
< |
int flags = Streams.STREAM_IS_SIZED; |
799 |
< |
return Streams.parallelStream |
800 |
< |
(() -> spliterator(0, size, modCount), flags); |
795 |
> |
return Streams.parallelStream(spliterator()); |
796 |
|
} |
797 |
|
|
798 |
< |
/** Index-based split-by-two Spliterator */ |
799 |
< |
static final class PriorityQueueSpliterator<E> |
800 |
< |
implements Spliterator<E>, Iterator<E> { |
798 |
> |
/** |
799 |
> |
* This is very similar to ArrayList Spliterator, except for extra |
800 |
> |
* null checks. |
801 |
> |
*/ |
802 |
> |
static final class PriorityQueueSpliterator<E> implements Spliterator<E> { |
803 |
|
private final PriorityQueue<E> pq; |
804 |
< |
private int index; // current index, modified on advance/split |
805 |
< |
private final int fence; // one past last index |
806 |
< |
private final int expectedModCount; // for comodification checks |
804 |
> |
private int index; // current index, modified on advance/split |
805 |
> |
private int fence; // -1 until first use |
806 |
> |
private int expectedModCount; // initialized when fence set |
807 |
|
|
808 |
< |
/** Create new spliterator covering the given range */ |
808 |
> |
/** Creates new spliterator covering the given range */ |
809 |
|
PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence, |
810 |
|
int expectedModCount) { |
811 |
< |
this.pq = pq; this.index = origin; this.fence = fence; |
811 |
> |
this.pq = pq; |
812 |
> |
this.index = origin; |
813 |
> |
this.fence = fence; |
814 |
|
this.expectedModCount = expectedModCount; |
815 |
|
} |
816 |
|
|
817 |
+ |
private int getFence() { // initialize fence to size on first use |
818 |
+ |
int hi; |
819 |
+ |
if ((hi = fence) < 0) { |
820 |
+ |
expectedModCount = pq.modCount; |
821 |
+ |
hi = fence = pq.size; |
822 |
+ |
} |
823 |
+ |
return hi; |
824 |
+ |
} |
825 |
+ |
|
826 |
|
public PriorityQueueSpliterator<E> trySplit() { |
827 |
< |
int lo = index, mid = (lo + fence) >>> 1; |
827 |
> |
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
828 |
|
return (lo >= mid) ? null : |
829 |
|
new PriorityQueueSpliterator<E>(pq, lo, index = mid, |
830 |
< |
expectedModCount); |
830 |
> |
expectedModCount); |
831 |
|
} |
832 |
|
|
833 |
< |
public void forEach(Block<? super E> block) { |
834 |
< |
Object[] a; int i, hi; // hoist accesses and checks from loop |
835 |
< |
if (block == null) |
833 |
> |
@SuppressWarnings("unchecked") |
834 |
> |
public void forEach(Consumer<? super E> action) { |
835 |
> |
int i, hi, mc; // hoist accesses and checks from loop |
836 |
> |
PriorityQueue<E> q; Object[] a; |
837 |
> |
if (action == null) |
838 |
|
throw new NullPointerException(); |
839 |
< |
if ((a = pq.queue).length >= (hi = fence) && |
840 |
< |
(i = index) >= 0 && i < hi) { |
841 |
< |
index = hi; |
842 |
< |
do { |
843 |
< |
@SuppressWarnings("unchecked") E e = (E) a[i]; |
844 |
< |
block.accept(e); |
845 |
< |
} while (++i < hi); |
846 |
< |
if (pq.modCount != expectedModCount) |
847 |
< |
throw new ConcurrentModificationException(); |
839 |
> |
if ((q = pq) != null && (a = q.queue) != null) { |
840 |
> |
if ((hi = fence) < 0) { |
841 |
> |
mc = q.modCount; |
842 |
> |
hi = q.size; |
843 |
> |
} |
844 |
> |
else |
845 |
> |
mc = expectedModCount; |
846 |
> |
if ((i = index) >= 0 && (index = hi) <= a.length) { |
847 |
> |
for (E e;; ++i) { |
848 |
> |
if (i < hi) { |
849 |
> |
if ((e = (E) a[i]) == null) // must be CME |
850 |
> |
break; |
851 |
> |
action.accept(e); |
852 |
> |
} |
853 |
> |
else if (q.modCount != mc) |
854 |
> |
break; |
855 |
> |
else |
856 |
> |
return; |
857 |
> |
} |
858 |
> |
} |
859 |
|
} |
860 |
+ |
throw new ConcurrentModificationException(); |
861 |
|
} |
862 |
|
|
863 |
< |
public boolean tryAdvance(Block<? super E> block) { |
864 |
< |
if (index >= 0 && index < fence) { |
863 |
> |
public boolean tryAdvance(Consumer<? super E> action) { |
864 |
> |
int hi = getFence(), lo = index; |
865 |
> |
if (lo >= 0 && lo < hi) { |
866 |
> |
index = lo + 1; |
867 |
> |
@SuppressWarnings("unchecked") E e = (E)pq.queue[lo]; |
868 |
> |
if (e == null) |
869 |
> |
throw new ConcurrentModificationException(); |
870 |
> |
action.accept(e); |
871 |
|
if (pq.modCount != expectedModCount) |
872 |
|
throw new ConcurrentModificationException(); |
845 |
– |
@SuppressWarnings("unchecked") E e = |
846 |
– |
(E)pq.queue[index++]; |
847 |
– |
block.accept(e); |
873 |
|
return true; |
874 |
|
} |
875 |
|
return false; |
876 |
|
} |
877 |
|
|
878 |
< |
public long estimateSize() { return (long)(fence - index); } |
879 |
< |
public boolean hasExactSize() { return true; } |
880 |
< |
public boolean hasExactSplits() { return true; } |
856 |
< |
|
857 |
< |
// Iterator support |
858 |
< |
public Iterator<E> iterator() { return this; } |
859 |
< |
public void remove() { throw new UnsupportedOperationException(); } |
860 |
< |
public boolean hasNext() { return index >= 0 && index < fence; } |
878 |
> |
public long estimateSize() { |
879 |
> |
return (long) (getFence() - index); |
880 |
> |
} |
881 |
|
|
882 |
< |
public E next() { |
883 |
< |
if (index < 0 || index >= fence) |
864 |
< |
throw new NoSuchElementException(); |
865 |
< |
if (pq.modCount != expectedModCount) |
866 |
< |
throw new ConcurrentModificationException(); |
867 |
< |
@SuppressWarnings("unchecked") E e = |
868 |
< |
(E) pq.queue[index++]; |
869 |
< |
return e; |
882 |
> |
public int characteristics() { |
883 |
> |
return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL; |
884 |
|
} |
885 |
|
} |
886 |
|
} |