| 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() { |
| 734 |
< |
for (int i = (size >>> 1) - 1; i >= 0; i--) |
| 735 |
< |
siftDown(i, (E) queue[i]); |
| 734 |
> |
final Object[] es = queue; |
| 735 |
> |
final int half = (size >>> 1) - 1; |
| 736 |
> |
if (comparator == null) |
| 737 |
> |
for (int i = half; i >= 0; i--) |
| 738 |
> |
siftDownComparable(i, (E) es[i]); |
| 739 |
> |
else |
| 740 |
> |
for (int i = half; i >= 0; i--) |
| 741 |
> |
siftDownUsingComparator(i, (E) es[i]); |
| 742 |
|
} |
| 743 |
|
|
| 744 |
|
/** |
| 757 |
|
/** |
| 758 |
|
* Saves this queue to a stream (that is, serializes it). |
| 759 |
|
* |
| 760 |
+ |
* @param s the stream |
| 761 |
+ |
* @throws java.io.IOException if an I/O error occurs |
| 762 |
|
* @serialData The length of the array backing the instance is |
| 763 |
|
* emitted (int), followed by all of its elements |
| 764 |
|
* (each an {@code Object}) in the proper order. |
| 755 |
– |
* @param s the stream |
| 756 |
– |
* @throws java.io.IOException if an I/O error occurs |
| 765 |
|
*/ |
| 766 |
|
private void writeObject(java.io.ObjectOutputStream s) |
| 767 |
|
throws java.io.IOException { |
| 807 |
|
/** |
| 808 |
|
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
| 809 |
|
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
| 810 |
< |
* queue. |
| 810 |
> |
* queue. The spliterator does not traverse elements in any particular order |
| 811 |
> |
* (the {@link Spliterator#ORDERED ORDERED} characteristic is not reported). |
| 812 |
|
* |
| 813 |
|
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
| 814 |
|
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}. |
| 819 |
|
* @since 1.8 |
| 820 |
|
*/ |
| 821 |
|
public final Spliterator<E> spliterator() { |
| 822 |
< |
return new PriorityQueueSpliterator<>(this, 0, -1, 0); |
| 822 |
> |
return new PriorityQueueSpliterator(0, -1, 0); |
| 823 |
|
} |
| 824 |
|
|
| 825 |
< |
static final class PriorityQueueSpliterator<E> implements Spliterator<E> { |
| 817 |
< |
/* |
| 818 |
< |
* This is very similar to ArrayList Spliterator, except for |
| 819 |
< |
* extra null checks. |
| 820 |
< |
*/ |
| 821 |
< |
private final PriorityQueue<E> pq; |
| 825 |
> |
final class PriorityQueueSpliterator implements Spliterator<E> { |
| 826 |
|
private int index; // current index, modified on advance/split |
| 827 |
|
private int fence; // -1 until first use |
| 828 |
|
private int expectedModCount; // initialized when fence set |
| 829 |
|
|
| 830 |
|
/** Creates new spliterator covering the given range. */ |
| 831 |
< |
PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence, |
| 828 |
< |
int expectedModCount) { |
| 829 |
< |
this.pq = pq; |
| 831 |
> |
PriorityQueueSpliterator(int origin, int fence, int expectedModCount) { |
| 832 |
|
this.index = origin; |
| 833 |
|
this.fence = fence; |
| 834 |
|
this.expectedModCount = expectedModCount; |
| 837 |
|
private int getFence() { // initialize fence to size on first use |
| 838 |
|
int hi; |
| 839 |
|
if ((hi = fence) < 0) { |
| 840 |
< |
expectedModCount = pq.modCount; |
| 841 |
< |
hi = fence = pq.size; |
| 840 |
> |
expectedModCount = modCount; |
| 841 |
> |
hi = fence = size; |
| 842 |
|
} |
| 843 |
|
return hi; |
| 844 |
|
} |
| 845 |
|
|
| 846 |
< |
public PriorityQueueSpliterator<E> trySplit() { |
| 846 |
> |
public PriorityQueueSpliterator trySplit() { |
| 847 |
|
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
| 848 |
|
return (lo >= mid) ? null : |
| 849 |
< |
new PriorityQueueSpliterator<>(pq, lo, index = mid, |
| 848 |
< |
expectedModCount); |
| 849 |
> |
new PriorityQueueSpliterator(lo, index = mid, expectedModCount); |
| 850 |
|
} |
| 851 |
|
|
| 852 |
|
@SuppressWarnings("unchecked") |
| 853 |
|
public void forEachRemaining(Consumer<? super E> action) { |
| 853 |
– |
int i, hi, mc; // hoist accesses and checks from loop |
| 854 |
– |
PriorityQueue<E> q; Object[] a; |
| 854 |
|
if (action == null) |
| 855 |
|
throw new NullPointerException(); |
| 856 |
< |
if ((q = pq) != null && (a = q.queue) != null) { |
| 857 |
< |
if ((hi = fence) < 0) { |
| 858 |
< |
mc = q.modCount; |
| 859 |
< |
hi = q.size; |
| 860 |
< |
} |
| 861 |
< |
else |
| 862 |
< |
mc = expectedModCount; |
| 864 |
< |
if ((i = index) >= 0 && (index = hi) <= a.length) { |
| 865 |
< |
for (E e;; ++i) { |
| 866 |
< |
if (i < hi) { |
| 867 |
< |
if ((e = (E) a[i]) == null) // must be CME |
| 868 |
< |
break; |
| 869 |
< |
action.accept(e); |
| 870 |
< |
} |
| 871 |
< |
else if (q.modCount != mc) |
| 872 |
< |
break; |
| 873 |
< |
else |
| 874 |
< |
return; |
| 875 |
< |
} |
| 876 |
< |
} |
| 856 |
> |
if (fence < 0) { fence = size; expectedModCount = modCount; } |
| 857 |
> |
final Object[] a = queue; |
| 858 |
> |
int i, hi; E e; |
| 859 |
> |
for (i = index, index = hi = fence; i < hi; i++) { |
| 860 |
> |
if ((e = (E) a[i]) == null) |
| 861 |
> |
break; // must be CME |
| 862 |
> |
action.accept(e); |
| 863 |
|
} |
| 864 |
< |
throw new ConcurrentModificationException(); |
| 864 |
> |
if (modCount != expectedModCount) |
| 865 |
> |
throw new ConcurrentModificationException(); |
| 866 |
|
} |
| 867 |
|
|
| 868 |
+ |
@SuppressWarnings("unchecked") |
| 869 |
|
public boolean tryAdvance(Consumer<? super E> action) { |
| 870 |
|
if (action == null) |
| 871 |
|
throw new NullPointerException(); |
| 872 |
< |
int hi = getFence(), lo = index; |
| 873 |
< |
if (lo >= 0 && lo < hi) { |
| 874 |
< |
index = lo + 1; |
| 875 |
< |
@SuppressWarnings("unchecked") E e = (E)pq.queue[lo]; |
| 876 |
< |
if (e == null) |
| 872 |
> |
if (fence < 0) { fence = size; expectedModCount = modCount; } |
| 873 |
> |
int i; |
| 874 |
> |
if ((i = index) < fence) { |
| 875 |
> |
index = i + 1; |
| 876 |
> |
E e; |
| 877 |
> |
if ((e = (E) queue[i]) == null |
| 878 |
> |
|| modCount != expectedModCount) |
| 879 |
|
throw new ConcurrentModificationException(); |
| 880 |
|
action.accept(e); |
| 891 |
– |
if (pq.modCount != expectedModCount) |
| 892 |
– |
throw new ConcurrentModificationException(); |
| 881 |
|
return true; |
| 882 |
|
} |
| 883 |
|
return false; |
| 884 |
|
} |
| 885 |
|
|
| 886 |
|
public long estimateSize() { |
| 887 |
< |
return (long) (getFence() - index); |
| 887 |
> |
return getFence() - index; |
| 888 |
|
} |
| 889 |
|
|
| 890 |
|
public int characteristics() { |
