1 |
|
/* |
2 |
< |
* %W% %E% |
2 |
> |
* Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved. |
3 |
> |
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 |
|
* |
5 |
< |
* Copyright 2006 Sun Microsystems, Inc. All rights reserved. |
6 |
< |
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
5 |
> |
* This code is free software; you can redistribute it and/or modify it |
6 |
> |
* under the terms of the GNU General Public License version 2 only, as |
7 |
> |
* published by the Free Software Foundation. Oracle designates this |
8 |
> |
* particular file as subject to the "Classpath" exception as provided |
9 |
> |
* by Oracle in the LICENSE file that accompanied this code. |
10 |
> |
* |
11 |
> |
* This code is distributed in the hope that it will be useful, but WITHOUT |
12 |
> |
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
13 |
> |
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
14 |
> |
* version 2 for more details (a copy is included in the LICENSE file that |
15 |
> |
* accompanied this code). |
16 |
> |
* |
17 |
> |
* You should have received a copy of the GNU General Public License version |
18 |
> |
* 2 along with this work; if not, write to the Free Software Foundation, |
19 |
> |
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
20 |
> |
* |
21 |
> |
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
22 |
> |
* or visit www.oracle.com if you need additional information or have any |
23 |
> |
* questions. |
24 |
|
*/ |
25 |
|
|
26 |
|
package java.util; |
27 |
|
|
28 |
+ |
import java.util.function.Consumer; |
29 |
+ |
import jdk.internal.misc.SharedSecrets; |
30 |
+ |
|
31 |
|
/** |
32 |
|
* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
33 |
|
* The elements of the priority queue are ordered according to their |
55 |
|
* <p>This class and its iterator implement all of the |
56 |
|
* <em>optional</em> methods of the {@link Collection} and {@link |
57 |
|
* Iterator} interfaces. The Iterator provided in method {@link |
58 |
< |
* #iterator()} is <em>not</em> guaranteed to traverse the elements of |
58 |
> |
* #iterator()} and the Spliterator provided in method {@link #spliterator()} |
59 |
> |
* are <em>not</em> guaranteed to traverse the elements of |
60 |
|
* the priority queue in any particular order. If you need ordered |
61 |
|
* traversal, consider using {@code Arrays.sort(pq.toArray())}. |
62 |
|
* |
63 |
< |
* <p> <strong>Note that this implementation is not synchronized.</strong> |
63 |
> |
* <p><strong>Note that this implementation is not synchronized.</strong> |
64 |
|
* Multiple threads should not access a {@code PriorityQueue} |
65 |
|
* instance concurrently if any of the threads modifies the queue. |
66 |
|
* Instead, use the thread-safe {@link |
67 |
|
* java.util.concurrent.PriorityBlockingQueue} class. |
68 |
|
* |
69 |
|
* <p>Implementation note: this implementation provides |
70 |
< |
* O(log(n)) time for the enqueing and dequeing methods |
70 |
> |
* O(log(n)) time for the enqueuing and dequeuing methods |
71 |
|
* ({@code offer}, {@code poll}, {@code remove()} and {@code add}); |
72 |
|
* linear time for the {@code remove(Object)} and {@code contains(Object)} |
73 |
|
* methods; and constant time for the retrieval methods |
74 |
|
* ({@code peek}, {@code element}, and {@code size}). |
75 |
|
* |
76 |
|
* <p>This class is a member of the |
77 |
< |
* <a href="{@docRoot}/../guide/collections/index.html"> |
77 |
> |
* <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework"> |
78 |
|
* Java Collections Framework</a>. |
79 |
|
* |
80 |
|
* @since 1.5 |
59 |
– |
* @version %I%, %G% |
81 |
|
* @author Josh Bloch, Doug Lea |
82 |
< |
* @param <E> the type of elements held in this collection |
82 |
> |
* @param <E> the type of elements held in this queue |
83 |
|
*/ |
84 |
+ |
@SuppressWarnings("unchecked") |
85 |
|
public class PriorityQueue<E> extends AbstractQueue<E> |
86 |
|
implements java.io.Serializable { |
87 |
|
|
97 |
|
* heap and each descendant d of n, n <= d. The element with the |
98 |
|
* lowest value is in queue[0], assuming the queue is nonempty. |
99 |
|
*/ |
100 |
< |
private transient Object[] queue; |
100 |
> |
transient Object[] queue; // non-private to simplify nested class access |
101 |
|
|
102 |
|
/** |
103 |
|
* The number of elements in the priority queue. |
104 |
|
*/ |
105 |
< |
private int size = 0; |
105 |
> |
int size; |
106 |
|
|
107 |
|
/** |
108 |
|
* The comparator, or null if priority queue uses elements' |
114 |
|
* The number of times this priority queue has been |
115 |
|
* <i>structurally modified</i>. See AbstractList for gory details. |
116 |
|
*/ |
117 |
< |
private transient int modCount = 0; |
117 |
> |
transient int modCount; // non-private to simplify nested class access |
118 |
|
|
119 |
|
/** |
120 |
|
* Creates a {@code PriorityQueue} with the default initial |
139 |
|
} |
140 |
|
|
141 |
|
/** |
142 |
+ |
* Creates a {@code PriorityQueue} with the default initial capacity and |
143 |
+ |
* whose elements are ordered according to the specified comparator. |
144 |
+ |
* |
145 |
+ |
* @param comparator the comparator that will be used to order this |
146 |
+ |
* priority queue. If {@code null}, the {@linkplain Comparable |
147 |
+ |
* natural ordering} of the elements will be used. |
148 |
+ |
* @since 1.8 |
149 |
+ |
*/ |
150 |
+ |
public PriorityQueue(Comparator<? super E> comparator) { |
151 |
+ |
this(DEFAULT_INITIAL_CAPACITY, comparator); |
152 |
+ |
} |
153 |
+ |
|
154 |
+ |
/** |
155 |
|
* Creates a {@code PriorityQueue} with the specified initial capacity |
156 |
|
* that orders its elements according to the specified comparator. |
157 |
|
* |
189 |
|
* of its elements are null |
190 |
|
*/ |
191 |
|
public PriorityQueue(Collection<? extends E> c) { |
192 |
< |
initFromCollection(c); |
193 |
< |
if (c instanceof SortedSet) |
194 |
< |
comparator = (Comparator<? super E>) |
195 |
< |
((SortedSet<? extends E>)c).comparator(); |
196 |
< |
else if (c instanceof PriorityQueue) |
197 |
< |
comparator = (Comparator<? super E>) |
198 |
< |
((PriorityQueue<? extends E>)c).comparator(); |
192 |
> |
if (c instanceof SortedSet<?>) { |
193 |
> |
SortedSet<? extends E> ss = (SortedSet<? extends E>) c; |
194 |
> |
this.comparator = (Comparator<? super E>) ss.comparator(); |
195 |
> |
initElementsFromCollection(ss); |
196 |
> |
} |
197 |
> |
else if (c instanceof PriorityQueue<?>) { |
198 |
> |
PriorityQueue<? extends E> pq = (PriorityQueue<? extends E>) c; |
199 |
> |
this.comparator = (Comparator<? super E>) pq.comparator(); |
200 |
> |
initFromPriorityQueue(pq); |
201 |
> |
} |
202 |
|
else { |
203 |
< |
comparator = null; |
204 |
< |
heapify(); |
203 |
> |
this.comparator = null; |
204 |
> |
initFromCollection(c); |
205 |
|
} |
206 |
|
} |
207 |
|
|
220 |
|
* of its elements are null |
221 |
|
*/ |
222 |
|
public PriorityQueue(PriorityQueue<? extends E> c) { |
223 |
< |
comparator = (Comparator<? super E>)c.comparator(); |
224 |
< |
initFromCollection(c); |
223 |
> |
this.comparator = (Comparator<? super E>) c.comparator(); |
224 |
> |
initFromPriorityQueue(c); |
225 |
|
} |
226 |
|
|
227 |
|
/** |
238 |
|
* of its elements are null |
239 |
|
*/ |
240 |
|
public PriorityQueue(SortedSet<? extends E> c) { |
241 |
< |
comparator = (Comparator<? super E>)c.comparator(); |
242 |
< |
initFromCollection(c); |
241 |
> |
this.comparator = (Comparator<? super E>) c.comparator(); |
242 |
> |
initElementsFromCollection(c); |
243 |
> |
} |
244 |
> |
|
245 |
> |
/** Ensures that queue[0] exists, helping peek() and poll(). */ |
246 |
> |
private static Object[] ensureNonEmpty(Object[] es) { |
247 |
> |
return (es.length > 0) ? es : new Object[1]; |
248 |
> |
} |
249 |
> |
|
250 |
> |
private void initFromPriorityQueue(PriorityQueue<? extends E> c) { |
251 |
> |
if (c.getClass() == PriorityQueue.class) { |
252 |
> |
this.queue = ensureNonEmpty(c.toArray()); |
253 |
> |
this.size = c.size(); |
254 |
> |
} else { |
255 |
> |
initFromCollection(c); |
256 |
> |
} |
257 |
> |
} |
258 |
> |
|
259 |
> |
private void initElementsFromCollection(Collection<? extends E> c) { |
260 |
> |
Object[] es = c.toArray(); |
261 |
> |
int len = es.length; |
262 |
> |
// If c.toArray incorrectly doesn't return Object[], copy it. |
263 |
> |
if (es.getClass() != Object[].class) |
264 |
> |
es = Arrays.copyOf(es, len, Object[].class); |
265 |
> |
if (len == 1 || this.comparator != null) |
266 |
> |
for (Object e : es) |
267 |
> |
if (e == null) |
268 |
> |
throw new NullPointerException(); |
269 |
> |
this.queue = ensureNonEmpty(es); |
270 |
> |
this.size = len; |
271 |
|
} |
272 |
|
|
273 |
|
/** |
276 |
|
* @param c the collection |
277 |
|
*/ |
278 |
|
private void initFromCollection(Collection<? extends E> c) { |
279 |
< |
Object[] a = c.toArray(); |
280 |
< |
// If c.toArray incorrectly doesn't return Object[], copy it. |
215 |
< |
if (a.getClass() != Object[].class) |
216 |
< |
a = Arrays.copyOf(a, a.length, Object[].class); |
217 |
< |
queue = a; |
218 |
< |
size = a.length; |
279 |
> |
initElementsFromCollection(c); |
280 |
> |
heapify(); |
281 |
|
} |
282 |
|
|
283 |
|
/** |
284 |
+ |
* The maximum size of array to allocate. |
285 |
+ |
* Some VMs reserve some header words in an array. |
286 |
+ |
* Attempts to allocate larger arrays may result in |
287 |
+ |
* OutOfMemoryError: Requested array size exceeds VM limit |
288 |
+ |
*/ |
289 |
+ |
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
290 |
+ |
|
291 |
+ |
/** |
292 |
|
* Increases the capacity of the array. |
293 |
|
* |
294 |
|
* @param minCapacity the desired minimum capacity |
295 |
|
*/ |
296 |
|
private void grow(int minCapacity) { |
297 |
< |
if (minCapacity < 0) // overflow |
228 |
< |
throw new OutOfMemoryError(); |
229 |
< |
int oldCapacity = queue.length; |
297 |
> |
int oldCapacity = queue.length; |
298 |
|
// Double size if small; else grow by 50% |
299 |
< |
int newCapacity = ((oldCapacity < 64)? |
300 |
< |
((oldCapacity + 1) * 2): |
301 |
< |
((oldCapacity / 2) * 3)); |
302 |
< |
if (newCapacity < 0) // overflow |
303 |
< |
newCapacity = Integer.MAX_VALUE; |
304 |
< |
if (newCapacity < minCapacity) |
237 |
< |
newCapacity = minCapacity; |
299 |
> |
int newCapacity = oldCapacity + ((oldCapacity < 64) ? |
300 |
> |
(oldCapacity + 2) : |
301 |
> |
(oldCapacity >> 1)); |
302 |
> |
// overflow-conscious code |
303 |
> |
if (newCapacity - MAX_ARRAY_SIZE > 0) |
304 |
> |
newCapacity = hugeCapacity(minCapacity); |
305 |
|
queue = Arrays.copyOf(queue, newCapacity); |
306 |
|
} |
307 |
|
|
308 |
+ |
private static int hugeCapacity(int minCapacity) { |
309 |
+ |
if (minCapacity < 0) // overflow |
310 |
+ |
throw new OutOfMemoryError(); |
311 |
+ |
return (minCapacity > MAX_ARRAY_SIZE) ? |
312 |
+ |
Integer.MAX_VALUE : |
313 |
+ |
MAX_ARRAY_SIZE; |
314 |
+ |
} |
315 |
+ |
|
316 |
|
/** |
317 |
|
* Inserts the specified element into this priority queue. |
318 |
|
* |
342 |
|
int i = size; |
343 |
|
if (i >= queue.length) |
344 |
|
grow(i + 1); |
345 |
+ |
siftUp(i, e); |
346 |
|
size = i + 1; |
271 |
– |
if (i == 0) |
272 |
– |
queue[0] = e; |
273 |
– |
else |
274 |
– |
siftUp(i, e); |
347 |
|
return true; |
348 |
|
} |
349 |
|
|
350 |
|
public E peek() { |
279 |
– |
if (size == 0) |
280 |
– |
return null; |
351 |
|
return (E) queue[0]; |
352 |
|
} |
353 |
|
|
354 |
|
private int indexOf(Object o) { |
355 |
< |
if (o != null) { |
356 |
< |
for (int i = 0; i < size; i++) |
357 |
< |
if (o.equals(queue[i])) |
355 |
> |
if (o != null) { |
356 |
> |
final Object[] es = queue; |
357 |
> |
for (int i = 0, n = size; i < n; i++) |
358 |
> |
if (o.equals(es[i])) |
359 |
|
return i; |
360 |
|
} |
361 |
|
return -1; |
373 |
|
* @return {@code true} if this queue changed as a result of the call |
374 |
|
*/ |
375 |
|
public boolean remove(Object o) { |
376 |
< |
int i = indexOf(o); |
377 |
< |
if (i == -1) |
378 |
< |
return false; |
379 |
< |
else { |
380 |
< |
removeAt(i); |
381 |
< |
return true; |
382 |
< |
} |
376 |
> |
int i = indexOf(o); |
377 |
> |
if (i == -1) |
378 |
> |
return false; |
379 |
> |
else { |
380 |
> |
removeAt(i); |
381 |
> |
return true; |
382 |
> |
} |
383 |
|
} |
384 |
|
|
385 |
|
/** |
386 |
< |
* Version of remove using reference equality, not equals. |
316 |
< |
* Needed by iterator.remove. |
386 |
> |
* Identity-based version for use in Itr.remove. |
387 |
|
* |
388 |
|
* @param o element to be removed from this queue, if present |
319 |
– |
* @return {@code true} if removed |
389 |
|
*/ |
390 |
< |
boolean removeEq(Object o) { |
391 |
< |
for (int i = 0; i < size; i++) { |
392 |
< |
if (o == queue[i]) { |
390 |
> |
void removeEq(Object o) { |
391 |
> |
final Object[] es = queue; |
392 |
> |
for (int i = 0, n = size; i < n; i++) { |
393 |
> |
if (o == es[i]) { |
394 |
|
removeAt(i); |
395 |
< |
return true; |
395 |
> |
break; |
396 |
|
} |
397 |
|
} |
328 |
– |
return false; |
398 |
|
} |
399 |
|
|
400 |
|
/** |
406 |
|
* @return {@code true} if this queue contains the specified element |
407 |
|
*/ |
408 |
|
public boolean contains(Object o) { |
409 |
< |
return indexOf(o) != -1; |
409 |
> |
return indexOf(o) >= 0; |
410 |
|
} |
411 |
|
|
412 |
|
/** |
444 |
|
* precise control over the runtime type of the output array, and may, |
445 |
|
* under certain circumstances, be used to save allocation costs. |
446 |
|
* |
447 |
< |
* <p>Suppose <tt>x</tt> is a queue known to contain only strings. |
447 |
> |
* <p>Suppose {@code x} is a queue known to contain only strings. |
448 |
|
* The following code can be used to dump the queue into a newly |
449 |
< |
* allocated array of <tt>String</tt>: |
449 |
> |
* allocated array of {@code String}: |
450 |
|
* |
451 |
< |
* <pre> |
383 |
< |
* String[] y = x.toArray(new String[0]);</pre> |
451 |
> |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
452 |
|
* |
453 |
< |
* Note that <tt>toArray(new Object[0])</tt> is identical in function to |
454 |
< |
* <tt>toArray()</tt>. |
453 |
> |
* Note that {@code toArray(new Object[0])} is identical in function to |
454 |
> |
* {@code toArray()}. |
455 |
|
* |
456 |
|
* @param a the array into which the elements of the queue are to |
457 |
|
* be stored, if it is big enough; otherwise, a new array of the |
463 |
|
* @throws NullPointerException if the specified array is null |
464 |
|
*/ |
465 |
|
public <T> T[] toArray(T[] a) { |
466 |
+ |
final int size = this.size; |
467 |
|
if (a.length < size) |
468 |
|
// Make a new array of a's runtime type, but my contents: |
469 |
|
return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
470 |
< |
System.arraycopy(queue, 0, a, 0, size); |
470 |
> |
System.arraycopy(queue, 0, a, 0, size); |
471 |
|
if (a.length > size) |
472 |
|
a[size] = null; |
473 |
|
return a; |
488 |
|
* Index (into queue array) of element to be returned by |
489 |
|
* subsequent call to next. |
490 |
|
*/ |
491 |
< |
private int cursor = 0; |
491 |
> |
private int cursor; |
492 |
|
|
493 |
|
/** |
494 |
|
* Index of element returned by most recent call to next, |
508 |
|
* We expect that most iterations, even those involving removals, |
509 |
|
* will not need to store elements in this field. |
510 |
|
*/ |
511 |
< |
private ArrayDeque<E> forgetMeNot = null; |
511 |
> |
private ArrayDeque<E> forgetMeNot; |
512 |
|
|
513 |
|
/** |
514 |
|
* Element returned by the most recent call to next iff that |
515 |
|
* element was drawn from the forgetMeNot list. |
516 |
|
*/ |
517 |
< |
private E lastRetElt = null; |
517 |
> |
private E lastRetElt; |
518 |
|
|
519 |
|
/** |
520 |
|
* The modCount value that the iterator believes that the backing |
523 |
|
*/ |
524 |
|
private int expectedModCount = modCount; |
525 |
|
|
526 |
+ |
Itr() {} // prevent access constructor creation |
527 |
+ |
|
528 |
|
public boolean hasNext() { |
529 |
|
return cursor < size || |
530 |
|
(forgetMeNot != null && !forgetMeNot.isEmpty()); |
554 |
|
cursor--; |
555 |
|
else { |
556 |
|
if (forgetMeNot == null) |
557 |
< |
forgetMeNot = new ArrayDeque<E>(); |
557 |
> |
forgetMeNot = new ArrayDeque<>(); |
558 |
|
forgetMeNot.add(moved); |
559 |
|
} |
560 |
|
} else if (lastRetElt != null) { |
562 |
|
lastRetElt = null; |
563 |
|
} else { |
564 |
|
throw new IllegalStateException(); |
565 |
< |
} |
565 |
> |
} |
566 |
|
expectedModCount = modCount; |
567 |
|
} |
568 |
|
} |
577 |
|
*/ |
578 |
|
public void clear() { |
579 |
|
modCount++; |
580 |
< |
for (int i = 0; i < size; i++) |
581 |
< |
queue[i] = null; |
580 |
> |
final Object[] es = queue; |
581 |
> |
for (int i = 0, n = size; i < n; i++) |
582 |
> |
es[i] = null; |
583 |
|
size = 0; |
584 |
|
} |
585 |
|
|
586 |
|
public E poll() { |
587 |
< |
if (size == 0) |
588 |
< |
return null; |
589 |
< |
int s = --size; |
590 |
< |
modCount++; |
591 |
< |
E result = (E) queue[0]; |
592 |
< |
E x = (E) queue[s]; |
593 |
< |
queue[s] = null; |
594 |
< |
if (s != 0) |
595 |
< |
siftDown(0, x); |
587 |
> |
final Object[] es; |
588 |
> |
final E result; |
589 |
> |
|
590 |
> |
if ((result = (E) ((es = queue)[0])) != null) { |
591 |
> |
modCount++; |
592 |
> |
final int n; |
593 |
> |
final E x = (E) es[(n = --size)]; |
594 |
> |
es[n] = null; |
595 |
> |
if (n > 0) { |
596 |
> |
final Comparator<? super E> cmp; |
597 |
> |
if ((cmp = comparator) == null) |
598 |
> |
siftDownComparable(0, x, es, n); |
599 |
> |
else |
600 |
> |
siftDownUsingComparator(0, x, es, n, cmp); |
601 |
> |
} |
602 |
> |
} |
603 |
|
return result; |
604 |
|
} |
605 |
|
|
615 |
|
* position before i. This fact is used by iterator.remove so as to |
616 |
|
* avoid missing traversing elements. |
617 |
|
*/ |
618 |
< |
private E removeAt(int i) { |
619 |
< |
assert i >= 0 && i < size; |
618 |
> |
E removeAt(int i) { |
619 |
> |
// assert i >= 0 && i < size; |
620 |
|
modCount++; |
621 |
|
int s = --size; |
622 |
|
if (s == i) // removed last element |
639 |
|
* promoting x up the tree until it is greater than or equal to |
640 |
|
* its parent, or is the root. |
641 |
|
* |
642 |
< |
* To simplify and speed up coercions and comparisons. the |
642 |
> |
* To simplify and speed up coercions and comparisons, the |
643 |
|
* Comparable and Comparator versions are separated into different |
644 |
|
* methods that are otherwise identical. (Similarly for siftDown.) |
645 |
|
* |
648 |
|
*/ |
649 |
|
private void siftUp(int k, E x) { |
650 |
|
if (comparator != null) |
651 |
< |
siftUpUsingComparator(k, x); |
651 |
> |
siftUpUsingComparator(k, x, queue, comparator); |
652 |
|
else |
653 |
< |
siftUpComparable(k, x); |
653 |
> |
siftUpComparable(k, x, queue); |
654 |
|
} |
655 |
|
|
656 |
< |
private void siftUpComparable(int k, E x) { |
657 |
< |
Comparable<? super E> key = (Comparable<? super E>) x; |
656 |
> |
private static <T> void siftUpComparable(int k, T x, Object[] es) { |
657 |
> |
Comparable<? super T> key = (Comparable<? super T>) x; |
658 |
|
while (k > 0) { |
659 |
|
int parent = (k - 1) >>> 1; |
660 |
< |
Object e = queue[parent]; |
661 |
< |
if (key.compareTo((E) e) >= 0) |
660 |
> |
Object e = es[parent]; |
661 |
> |
if (key.compareTo((T) e) >= 0) |
662 |
|
break; |
663 |
< |
queue[k] = e; |
663 |
> |
es[k] = e; |
664 |
|
k = parent; |
665 |
|
} |
666 |
< |
queue[k] = key; |
666 |
> |
es[k] = key; |
667 |
|
} |
668 |
|
|
669 |
< |
private void siftUpUsingComparator(int k, E x) { |
669 |
> |
private static <T> void siftUpUsingComparator( |
670 |
> |
int k, T x, Object[] es, Comparator<? super T> cmp) { |
671 |
|
while (k > 0) { |
672 |
|
int parent = (k - 1) >>> 1; |
673 |
< |
Object e = queue[parent]; |
674 |
< |
if (comparator.compare(x, (E) e) >= 0) |
673 |
> |
Object e = es[parent]; |
674 |
> |
if (cmp.compare(x, (T) e) >= 0) |
675 |
|
break; |
676 |
< |
queue[k] = e; |
676 |
> |
es[k] = e; |
677 |
|
k = parent; |
678 |
|
} |
679 |
< |
queue[k] = x; |
679 |
> |
es[k] = x; |
680 |
|
} |
681 |
|
|
682 |
|
/** |
689 |
|
*/ |
690 |
|
private void siftDown(int k, E x) { |
691 |
|
if (comparator != null) |
692 |
< |
siftDownUsingComparator(k, x); |
692 |
> |
siftDownUsingComparator(k, x, queue, size, comparator); |
693 |
|
else |
694 |
< |
siftDownComparable(k, x); |
694 |
> |
siftDownComparable(k, x, queue, size); |
695 |
|
} |
696 |
|
|
697 |
< |
private void siftDownComparable(int k, E x) { |
698 |
< |
Comparable<? super E> key = (Comparable<? super E>)x; |
699 |
< |
int half = size >>> 1; // loop while a non-leaf |
697 |
> |
private static <T> void siftDownComparable(int k, T x, Object[] es, int n) { |
698 |
> |
// assert n > 0; |
699 |
> |
Comparable<? super T> key = (Comparable<? super T>)x; |
700 |
> |
int half = n >>> 1; // loop while a non-leaf |
701 |
|
while (k < half) { |
702 |
|
int child = (k << 1) + 1; // assume left child is least |
703 |
< |
Object c = queue[child]; |
703 |
> |
Object c = es[child]; |
704 |
|
int right = child + 1; |
705 |
< |
if (right < size && |
706 |
< |
((Comparable<? super E>) c).compareTo((E) queue[right]) > 0) |
707 |
< |
c = queue[child = right]; |
708 |
< |
if (key.compareTo((E) c) <= 0) |
705 |
> |
if (right < n && |
706 |
> |
((Comparable<? super T>) c).compareTo((T) es[right]) > 0) |
707 |
> |
c = es[child = right]; |
708 |
> |
if (key.compareTo((T) c) <= 0) |
709 |
|
break; |
710 |
< |
queue[k] = c; |
710 |
> |
es[k] = c; |
711 |
|
k = child; |
712 |
|
} |
713 |
< |
queue[k] = key; |
713 |
> |
es[k] = key; |
714 |
|
} |
715 |
|
|
716 |
< |
private void siftDownUsingComparator(int k, E x) { |
717 |
< |
int half = size >>> 1; |
716 |
> |
private static <T> void siftDownUsingComparator( |
717 |
> |
int k, T x, Object[] es, int n, Comparator<? super T> cmp) { |
718 |
> |
// assert n > 0; |
719 |
> |
int half = n >>> 1; |
720 |
|
while (k < half) { |
721 |
|
int child = (k << 1) + 1; |
722 |
< |
Object c = queue[child]; |
722 |
> |
Object c = es[child]; |
723 |
|
int right = child + 1; |
724 |
< |
if (right < size && |
725 |
< |
comparator.compare((E) c, (E) queue[right]) > 0) |
726 |
< |
c = queue[child = right]; |
644 |
< |
if (comparator.compare(x, (E) c) <= 0) |
724 |
> |
if (right < n && cmp.compare((T) c, (T) es[right]) > 0) |
725 |
> |
c = es[child = right]; |
726 |
> |
if (cmp.compare(x, (T) c) <= 0) |
727 |
|
break; |
728 |
< |
queue[k] = c; |
728 |
> |
es[k] = c; |
729 |
|
k = child; |
730 |
|
} |
731 |
< |
queue[k] = x; |
731 |
> |
es[k] = x; |
732 |
|
} |
733 |
|
|
734 |
|
/** |
735 |
|
* Establishes the heap invariant (described above) in the entire tree, |
736 |
|
* assuming nothing about the order of the elements prior to the call. |
737 |
+ |
* This classic algorithm due to Floyd (1964) is known to be O(size). |
738 |
|
*/ |
739 |
|
private void heapify() { |
740 |
< |
for (int i = (size >>> 1) - 1; i >= 0; i--) |
741 |
< |
siftDown(i, (E) queue[i]); |
740 |
> |
final Object[] es = queue; |
741 |
> |
int n = size, i = (n >>> 1) - 1; |
742 |
> |
final Comparator<? super E> cmp; |
743 |
> |
if ((cmp = comparator) == null) |
744 |
> |
for (; i >= 0; i--) |
745 |
> |
siftDownComparable(i, (E) es[i], es, n); |
746 |
> |
else |
747 |
> |
for (; i >= 0; i--) |
748 |
> |
siftDownUsingComparator(i, (E) es[i], es, n, cmp); |
749 |
|
} |
750 |
|
|
751 |
|
/** |
762 |
|
} |
763 |
|
|
764 |
|
/** |
765 |
< |
* Saves the state of the instance to a stream (that |
676 |
< |
* is, serializes it). |
765 |
> |
* Saves this queue to a stream (that is, serializes it). |
766 |
|
* |
767 |
+ |
* @param s the stream |
768 |
+ |
* @throws java.io.IOException if an I/O error occurs |
769 |
|
* @serialData The length of the array backing the instance is |
770 |
|
* emitted (int), followed by all of its elements |
771 |
|
* (each an {@code Object}) in the proper order. |
681 |
– |
* @param s the stream |
772 |
|
*/ |
773 |
|
private void writeObject(java.io.ObjectOutputStream s) |
774 |
< |
throws java.io.IOException{ |
774 |
> |
throws java.io.IOException { |
775 |
|
// Write out element count, and any hidden stuff |
776 |
|
s.defaultWriteObject(); |
777 |
|
|
778 |
|
// Write out array length, for compatibility with 1.5 version |
779 |
|
s.writeInt(Math.max(2, size + 1)); |
780 |
|
|
781 |
< |
// Write out all elements in the proper order. |
782 |
< |
for (int i = 0; i < size; i++) |
783 |
< |
s.writeObject(queue[i]); |
781 |
> |
// Write out all elements in the "proper order". |
782 |
> |
final Object[] es = queue; |
783 |
> |
for (int i = 0, n = size; i < n; i++) |
784 |
> |
s.writeObject(es[i]); |
785 |
|
} |
786 |
|
|
787 |
|
/** |
789 |
|
* (that is, deserializes it). |
790 |
|
* |
791 |
|
* @param s the stream |
792 |
+ |
* @throws ClassNotFoundException if the class of a serialized object |
793 |
+ |
* could not be found |
794 |
+ |
* @throws java.io.IOException if an I/O error occurs |
795 |
|
*/ |
796 |
|
private void readObject(java.io.ObjectInputStream s) |
797 |
|
throws java.io.IOException, ClassNotFoundException { |
801 |
|
// Read in (and discard) array length |
802 |
|
s.readInt(); |
803 |
|
|
804 |
< |
queue = new Object[size]; |
804 |
> |
SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size); |
805 |
> |
final Object[] es = queue = new Object[Math.max(size, 1)]; |
806 |
> |
|
807 |
> |
// Read in all elements. |
808 |
> |
for (int i = 0, n = size; i < n; i++) |
809 |
> |
es[i] = s.readObject(); |
810 |
> |
|
811 |
> |
// Elements are guaranteed to be in "proper order", but the |
812 |
> |
// spec has never explained what that might be. |
813 |
> |
heapify(); |
814 |
> |
} |
815 |
> |
|
816 |
> |
/** |
817 |
> |
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
818 |
> |
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
819 |
> |
* queue. The spliterator does not traverse elements in any particular order |
820 |
> |
* (the {@link Spliterator#ORDERED ORDERED} characteristic is not reported). |
821 |
> |
* |
822 |
> |
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
823 |
> |
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}. |
824 |
> |
* Overriding implementations should document the reporting of additional |
825 |
> |
* characteristic values. |
826 |
> |
* |
827 |
> |
* @return a {@code Spliterator} over the elements in this queue |
828 |
> |
* @since 1.8 |
829 |
> |
*/ |
830 |
> |
public final Spliterator<E> spliterator() { |
831 |
> |
return new PriorityQueueSpliterator(0, -1, 0); |
832 |
> |
} |
833 |
> |
|
834 |
> |
final class PriorityQueueSpliterator implements Spliterator<E> { |
835 |
> |
private int index; // current index, modified on advance/split |
836 |
> |
private int fence; // -1 until first use |
837 |
> |
private int expectedModCount; // initialized when fence set |
838 |
> |
|
839 |
> |
/** Creates new spliterator covering the given range. */ |
840 |
> |
PriorityQueueSpliterator(int origin, int fence, int expectedModCount) { |
841 |
> |
this.index = origin; |
842 |
> |
this.fence = fence; |
843 |
> |
this.expectedModCount = expectedModCount; |
844 |
> |
} |
845 |
> |
|
846 |
> |
private int getFence() { // initialize fence to size on first use |
847 |
> |
int hi; |
848 |
> |
if ((hi = fence) < 0) { |
849 |
> |
expectedModCount = modCount; |
850 |
> |
hi = fence = size; |
851 |
> |
} |
852 |
> |
return hi; |
853 |
> |
} |
854 |
> |
|
855 |
> |
public PriorityQueueSpliterator trySplit() { |
856 |
> |
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
857 |
> |
return (lo >= mid) ? null : |
858 |
> |
new PriorityQueueSpliterator(lo, index = mid, expectedModCount); |
859 |
> |
} |
860 |
> |
|
861 |
> |
public void forEachRemaining(Consumer<? super E> action) { |
862 |
> |
if (action == null) |
863 |
> |
throw new NullPointerException(); |
864 |
> |
if (fence < 0) { fence = size; expectedModCount = modCount; } |
865 |
> |
final Object[] es = queue; |
866 |
> |
int i, hi; E e; |
867 |
> |
for (i = index, index = hi = fence; i < hi; i++) { |
868 |
> |
if ((e = (E) es[i]) == null) |
869 |
> |
break; // must be CME |
870 |
> |
action.accept(e); |
871 |
> |
} |
872 |
> |
if (modCount != expectedModCount) |
873 |
> |
throw new ConcurrentModificationException(); |
874 |
> |
} |
875 |
|
|
876 |
< |
// Read in all elements in the proper order. |
877 |
< |
for (int i = 0; i < size; i++) |
878 |
< |
queue[i] = s.readObject(); |
876 |
> |
public boolean tryAdvance(Consumer<? super E> action) { |
877 |
> |
if (action == null) |
878 |
> |
throw new NullPointerException(); |
879 |
> |
if (fence < 0) { fence = size; expectedModCount = modCount; } |
880 |
> |
int i; |
881 |
> |
if ((i = index) < fence) { |
882 |
> |
index = i + 1; |
883 |
> |
E e; |
884 |
> |
if ((e = (E) queue[i]) == null |
885 |
> |
|| modCount != expectedModCount) |
886 |
> |
throw new ConcurrentModificationException(); |
887 |
> |
action.accept(e); |
888 |
> |
return true; |
889 |
> |
} |
890 |
> |
return false; |
891 |
> |
} |
892 |
> |
|
893 |
> |
public long estimateSize() { |
894 |
> |
return getFence() - index; |
895 |
> |
} |
896 |
> |
|
897 |
> |
public int characteristics() { |
898 |
> |
return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL; |
899 |
> |
} |
900 |
> |
} |
901 |
> |
|
902 |
> |
/** |
903 |
> |
* @throws NullPointerException {@inheritDoc} |
904 |
> |
*/ |
905 |
> |
public void forEach(Consumer<? super E> action) { |
906 |
> |
Objects.requireNonNull(action); |
907 |
> |
final int expectedModCount = modCount; |
908 |
> |
final Object[] es = queue; |
909 |
> |
for (int i = 0, n = size; i < n; i++) |
910 |
> |
action.accept((E) es[i]); |
911 |
> |
if (expectedModCount != modCount) |
912 |
> |
throw new ConcurrentModificationException(); |
913 |
|
} |
914 |
|
} |