54 |
|
* <p>This class and its iterator implement all of the |
55 |
|
* <em>optional</em> methods of the {@link Collection} and {@link |
56 |
|
* Iterator} interfaces. The Iterator provided in method {@link |
57 |
< |
* #iterator()} is <em>not</em> guaranteed to traverse the elements of |
57 |
> |
* #iterator()} and the Spliterator provided in method {@link #spliterator()} |
58 |
> |
* are <em>not</em> guaranteed to traverse the elements of |
59 |
|
* the priority queue in any particular order. If you need ordered |
60 |
|
* traversal, consider using {@code Arrays.sort(pq.toArray())}. |
61 |
|
* |
727 |
|
/** |
728 |
|
* Establishes the heap invariant (described above) in the entire tree, |
729 |
|
* assuming nothing about the order of the elements prior to the call. |
730 |
+ |
* This classic algorithm due to Floyd (1964) is known to be O(size). |
731 |
|
*/ |
732 |
|
@SuppressWarnings("unchecked") |
733 |
|
private void heapify() { |
751 |
|
/** |
752 |
|
* Saves this queue to a stream (that is, serializes it). |
753 |
|
* |
754 |
+ |
* @param s the stream |
755 |
+ |
* @throws java.io.IOException if an I/O error occurs |
756 |
|
* @serialData The length of the array backing the instance is |
757 |
|
* emitted (int), followed by all of its elements |
758 |
|
* (each an {@code Object}) in the proper order. |
755 |
– |
* @param s the stream |
756 |
– |
* @throws java.io.IOException if an I/O error occurs |
759 |
|
*/ |
760 |
|
private void writeObject(java.io.ObjectOutputStream s) |
761 |
|
throws java.io.IOException { |
801 |
|
/** |
802 |
|
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
803 |
|
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
804 |
< |
* queue. |
804 |
> |
* queue. The spliterator does not traverse elements in any particular order |
805 |
> |
* (the {@link Spliterator#ORDERED ORDERED} characteristic is not reported). |
806 |
|
* |
807 |
|
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
808 |
|
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}. |
813 |
|
* @since 1.8 |
814 |
|
*/ |
815 |
|
public final Spliterator<E> spliterator() { |
816 |
< |
return new PriorityQueueSpliterator<>(this, 0, -1, 0); |
816 |
> |
return new PriorityQueueSpliterator(0, -1, 0); |
817 |
|
} |
818 |
|
|
819 |
< |
static final class PriorityQueueSpliterator<E> implements Spliterator<E> { |
819 |
> |
final class PriorityQueueSpliterator implements Spliterator<E> { |
820 |
|
/* |
821 |
|
* This is very similar to ArrayList Spliterator, except for |
822 |
|
* extra null checks. |
823 |
|
*/ |
821 |
– |
private final PriorityQueue<E> pq; |
824 |
|
private int index; // current index, modified on advance/split |
825 |
|
private int fence; // -1 until first use |
826 |
|
private int expectedModCount; // initialized when fence set |
827 |
|
|
828 |
|
/** Creates new spliterator covering the given range. */ |
829 |
< |
PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence, |
828 |
< |
int expectedModCount) { |
829 |
< |
this.pq = pq; |
829 |
> |
PriorityQueueSpliterator(int origin, int fence, int expectedModCount) { |
830 |
|
this.index = origin; |
831 |
|
this.fence = fence; |
832 |
|
this.expectedModCount = expectedModCount; |
835 |
|
private int getFence() { // initialize fence to size on first use |
836 |
|
int hi; |
837 |
|
if ((hi = fence) < 0) { |
838 |
< |
expectedModCount = pq.modCount; |
839 |
< |
hi = fence = pq.size; |
838 |
> |
expectedModCount = modCount; |
839 |
> |
hi = fence = size; |
840 |
|
} |
841 |
|
return hi; |
842 |
|
} |
843 |
|
|
844 |
< |
public PriorityQueueSpliterator<E> trySplit() { |
844 |
> |
public PriorityQueueSpliterator trySplit() { |
845 |
|
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
846 |
|
return (lo >= mid) ? null : |
847 |
< |
new PriorityQueueSpliterator<>(pq, lo, index = mid, |
848 |
< |
expectedModCount); |
847 |
> |
new PriorityQueueSpliterator(lo, index = mid, expectedModCount); |
848 |
|
} |
849 |
|
|
850 |
|
@SuppressWarnings("unchecked") |
851 |
|
public void forEachRemaining(Consumer<? super E> action) { |
852 |
|
int i, hi, mc; // hoist accesses and checks from loop |
853 |
< |
PriorityQueue<E> q; Object[] a; |
853 |
> |
final Object[] a; |
854 |
|
if (action == null) |
855 |
|
throw new NullPointerException(); |
856 |
< |
if ((q = pq) != null && (a = q.queue) != null) { |
856 |
> |
if ((a = queue) != null) { |
857 |
|
if ((hi = fence) < 0) { |
858 |
< |
mc = q.modCount; |
859 |
< |
hi = q.size; |
858 |
> |
mc = modCount; |
859 |
> |
hi = size; |
860 |
|
} |
861 |
|
else |
862 |
|
mc = expectedModCount; |
867 |
|
break; |
868 |
|
action.accept(e); |
869 |
|
} |
870 |
< |
else if (q.modCount != mc) |
870 |
> |
else if (modCount != mc) |
871 |
|
break; |
872 |
|
else |
873 |
|
return; |
883 |
|
int hi = getFence(), lo = index; |
884 |
|
if (lo >= 0 && lo < hi) { |
885 |
|
index = lo + 1; |
886 |
< |
@SuppressWarnings("unchecked") E e = (E)pq.queue[lo]; |
886 |
> |
@SuppressWarnings("unchecked") E e = (E)queue[lo]; |
887 |
|
if (e == null) |
888 |
|
throw new ConcurrentModificationException(); |
889 |
|
action.accept(e); |
890 |
< |
if (pq.modCount != expectedModCount) |
890 |
> |
if (modCount != expectedModCount) |
891 |
|
throw new ConcurrentModificationException(); |
892 |
|
return true; |
893 |
|
} |
895 |
|
} |
896 |
|
|
897 |
|
public long estimateSize() { |
898 |
< |
return (long) (getFence() - index); |
898 |
> |
return getFence() - index; |
899 |
|
} |
900 |
|
|
901 |
|
public int characteristics() { |