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root/jsr166/jsr166/src/main/java/util/PriorityQueue.java

Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.121 by jsr166, Wed Mar 28 02:50:41 2018 UTC vs.
Revision 1.127 by jsr166, Sun May 6 23:09:28 2018 UTC

#	Line 81 | Line 81 | import jdk.internal.misc.SharedSecrets;
81		* @author Josh Bloch, Doug Lea
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
#	Line 187 | Line 188 | public class PriorityQueue<E> extends Ab
188		* @throws NullPointerException if the specified collection or any
189		*         of its elements are null
190		*/
190	–	@SuppressWarnings("unchecked")
191		public PriorityQueue(Collection<? extends E> c) {
192		if (c instanceof SortedSet<?>) {
193		SortedSet<? extends E> ss = (SortedSet<? extends E>) c;
#	Line 219 | Line 219 | public class PriorityQueue<E> extends Ab
219		* @throws NullPointerException if the specified priority queue or any
220		*         of its elements are null
221		*/
222	–	@SuppressWarnings("unchecked")
222		public PriorityQueue(PriorityQueue<? extends E> c) {
223		this.comparator = (Comparator<? super E>) c.comparator();
224		initFromPriorityQueue(c);
#	Line 238 | Line 237 | public class PriorityQueue<E> extends Ab
237		* @throws NullPointerException if the specified sorted set or any
238		*         of its elements are null
239		*/
241	–	@SuppressWarnings("unchecked")
240		public PriorityQueue(SortedSet<? extends E> 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 = c.toArray();
252	>	this.queue = ensureNonEmpty(c.toArray());
253		this.size = c.size();
254		} else {
255		initFromCollection(c);
#	Line 254 | Line 257 | public class PriorityQueue<E> extends Ab
257		}
258
259		private void initElementsFromCollection(Collection<? extends E> c) {
260	<	Object[] a = c.toArray();
260	>	Object[] es = c.toArray();
261	>	int len = es.length;
262		// If c.toArray incorrectly doesn't return Object[], copy it.
263	<	if (a.getClass() != Object[].class)
264	<	a = Arrays.copyOf(a, a.length, Object[].class);
261	<	int len = a.length;
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 : a)
266	>	for (Object e : es)
267		if (e == null)
268		throw new NullPointerException();
269	<	this.queue = a;
270	<	this.size = a.length;
269	>	this.queue = ensureNonEmpty(es);
270	>	this.size = len;
271		}
272
273		/**
#	Line 344 | Line 347 | public class PriorityQueue<E> extends Ab
347		return true;
348		}
349
347	–	@SuppressWarnings("unchecked")
350		public E peek() {
351	<	return (size == 0) ? null : (E) queue[0];
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]))
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;
#	Line 380 | Line 383 | public class PriorityQueue<E> extends Ab
383		}
384
385		/**
386	<	* Version of remove using reference equality, not equals.
384	<	* 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
387	–	* @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		}
396	–	return false;
398		}
399
400		/**
#	Line 461 | Line 462 | public class PriorityQueue<E> extends Ab
462		*         this queue
463		* @throws NullPointerException if the specified array is null
464		*/
464	–	@SuppressWarnings("unchecked")
465		public <T> T[] toArray(T[] a) {
466		final int size = this.size;
467		if (a.length < size)
#	Line 530 | Line 530 | public class PriorityQueue<E> extends Ab
530		(forgetMeNot != null && !forgetMeNot.isEmpty());
531		}
532
533	–	@SuppressWarnings("unchecked")
533		public E next() {
534		if (expectedModCount != modCount)
535		throw new ConcurrentModificationException();
#	Line 578 | Line 577 | public class PriorityQueue<E> extends Ab
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	–	@SuppressWarnings("unchecked")
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
#	Line 609 | Line 615 | public class PriorityQueue<E> extends Ab
615		* position before i. This fact is used by iterator.remove so as to
616		* avoid missing traversing elements.
617		*/
612	–	@SuppressWarnings("unchecked")
618		E removeAt(int i) {
619		// assert i >= 0 && i < size;
620	+	final Object[] es = queue;
621		modCount++;
622		int s = --size;
623		if (s == i) // removed last element
624	<	queue[i] = null;
624	>	es[i] = null;
625		else {
626	<	E moved = (E) queue[s];
627	<	queue[s] = null;
626	>	E moved = (E) es[s];
627	>	es[s] = null;
628		siftDown(i, moved);
629	<	if (queue[i] == moved) {
629	>	if (es[i] == moved) {
630		siftUp(i, moved);
631	<	if (queue[i] != moved)
631	>	if (es[i] != moved)
632		return moved;
633		}
634		}
#	Line 643 | Line 649 | public class PriorityQueue<E> extends Ab
649		*/
650		private void siftUp(int k, E x) {
651		if (comparator != null)
652	<	siftUpUsingComparator(k, x);
652	>	siftUpUsingComparator(k, x, queue, comparator);
653		else
654	<	siftUpComparable(k, x);
654	>	siftUpComparable(k, x, queue);
655		}
656
657	<	@SuppressWarnings("unchecked")
658	<	private void siftUpComparable(int k, E x) {
653	<	Comparable<? super E> key = (Comparable<? super E>) x;
657	>	private static <T> void siftUpComparable(int k, T x, Object[] es) {
658	>	Comparable<? super T> key = (Comparable<? super T>) x;
659		while (k > 0) {
660		int parent = (k - 1) >>> 1;
661	<	Object e = queue[parent];
662	<	if (key.compareTo((E) e) >= 0)
661	>	Object e = es[parent];
662	>	if (key.compareTo((T) e) >= 0)
663		break;
664	<	queue[k] = e;
664	>	es[k] = e;
665		k = parent;
666		}
667	<	queue[k] = key;
667	>	es[k] = key;
668		}
669
670	<	@SuppressWarnings("unchecked")
671	<	private void siftUpUsingComparator(int k, E x) {
670	>	private static <T> void siftUpUsingComparator(
671	>	int k, T x, Object[] es, Comparator<? super T> cmp) {
672		while (k > 0) {
673		int parent = (k - 1) >>> 1;
674	<	Object e = queue[parent];
675	<	if (comparator.compare(x, (E) e) >= 0)
674	>	Object e = es[parent];
675	>	if (cmp.compare(x, (T) e) >= 0)
676		break;
677	<	queue[k] = e;
677	>	es[k] = e;
678		k = parent;
679		}
680	<	queue[k] = x;
680	>	es[k] = x;
681		}
682
683		/**
#	Line 685 | Line 690 | public class PriorityQueue<E> extends Ab
690		*/
691		private void siftDown(int k, E x) {
692		if (comparator != null)
693	<	siftDownUsingComparator(k, x);
693	>	siftDownUsingComparator(k, x, queue, size, comparator);
694		else
695	<	siftDownComparable(k, x);
695	>	siftDownComparable(k, x, queue, size);
696		}
697
698	<	@SuppressWarnings("unchecked")
699	<	private void siftDownComparable(int k, E x) {
700	<	Comparable<? super E> key = (Comparable<? super E>)x;
701	<	int half = size >>> 1;        // loop while a non-leaf
698	>	private static <T> void siftDownComparable(int k, T x, Object[] es, int n) {
699	>	// assert n > 0;
700	>	Comparable<? super T> key = (Comparable<? super T>)x;
701	>	int half = n >>> 1;           // loop while a non-leaf
702		while (k < half) {
703		int child = (k << 1) + 1; // assume left child is least
704	<	Object c = queue[child];
704	>	Object c = es[child];
705		int right = child + 1;
706	<	if (right < size &&
707	<	((Comparable<? super E>) c).compareTo((E) queue[right]) > 0)
708	<	c = queue[child = right];
709	<	if (key.compareTo((E) c) <= 0)
706	>	if (right < n &&
707	>	((Comparable<? super T>) c).compareTo((T) es[right]) > 0)
708	>	c = es[child = right];
709	>	if (key.compareTo((T) c) <= 0)
710		break;
711	<	queue[k] = c;
711	>	es[k] = c;
712		k = child;
713		}
714	<	queue[k] = key;
714	>	es[k] = key;
715		}
716
717	<	@SuppressWarnings("unchecked")
718	<	private void siftDownUsingComparator(int k, E x) {
719	<	int half = size >>> 1;
717	>	private static <T> void siftDownUsingComparator(
718	>	int k, T x, Object[] es, int n, Comparator<? super T> cmp) {
719	>	// assert n > 0;
720	>	int half = n >>> 1;
721		while (k < half) {
722		int child = (k << 1) + 1;
723	<	Object c = queue[child];
723	>	Object c = es[child];
724		int right = child + 1;
725	<	if (right < size &&
726	<	comparator.compare((E) c, (E) queue[right]) > 0)
727	<	c = queue[child = right];
722	<	if (comparator.compare(x, (E) c) <= 0)
725	>	if (right < n && cmp.compare((T) c, (T) es[right]) > 0)
726	>	c = es[child = right];
727	>	if (cmp.compare(x, (T) c) <= 0)
728		break;
729	<	queue[k] = c;
729	>	es[k] = c;
730		k = child;
731		}
732	<	queue[k] = x;
732	>	es[k] = x;
733		}
734
735		/**
#	Line 732 | Line 737 | public class PriorityQueue<E> extends Ab
737		* assuming nothing about the order of the elements prior to the call.
738		* This classic algorithm due to Floyd (1964) is known to be O(size).
739		*/
735	–	@SuppressWarnings("unchecked")
740		private void heapify() {
741		final Object[] es = queue;
742	<	int i = (size >>> 1) - 1;
743	<	if (comparator == null)
742	>	int n = size, i = (n >>> 1) - 1;
743	>	final Comparator<? super E> cmp;
744	>	if ((cmp = comparator) == null)
745		for (; i >= 0; i--)
746	<	siftDownComparable(i, (E) es[i]);
746	>	siftDownComparable(i, (E) es[i], es, n);
747		else
748		for (; i >= 0; i--)
749	<	siftDownUsingComparator(i, (E) es[i]);
749	>	siftDownUsingComparator(i, (E) es[i], es, n, cmp);
750		}
751
752		/**
#	Line 775 | Line 780 | public class PriorityQueue<E> extends Ab
780		s.writeInt(Math.max(2, size + 1));
781
782		// Write out all elements in the "proper order".
783	<	for (int i = 0; i < size; i++)
784	<	s.writeObject(queue[i]);
783	>	final Object[] es = queue;
784	>	for (int i = 0, n = size; i < n; i++)
785	>	s.writeObject(es[i]);
786		}
787
788		/**
#	Line 797 | Line 803 | public class PriorityQueue<E> extends Ab
803		s.readInt();
804
805		SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size);
806	<	queue = new Object[size];
806	>	final Object[] es = queue = new Object[Math.max(size, 1)];
807
808		// Read in all elements.
809	<	for (int i = 0; i < size; i++)
810	<	queue[i] = s.readObject();
809	>	for (int i = 0, n = size; i < n; i++)
810	>	es[i] = s.readObject();
811
812		// Elements are guaranteed to be in "proper order", but the
813		// spec has never explained what that might be.
#	Line 853 | Line 859 | public class PriorityQueue<E> extends Ab
859		new PriorityQueueSpliterator(lo, index = mid, expectedModCount);
860		}
861
856	–	@SuppressWarnings("unchecked")
862		public void forEachRemaining(Consumer<? super E> action) {
863		if (action == null)
864		throw new NullPointerException();
865		if (fence < 0) { fence = size; expectedModCount = modCount; }
866	<	final Object[] a = queue;
866	>	final Object[] es = queue;
867		int i, hi; E e;
868		for (i = index, index = hi = fence; i < hi; i++) {
869	<	if ((e = (E) a[i]) == null)
869	>	if ((e = (E) es[i]) == null)
870		break;      // must be CME
871		action.accept(e);
872		}
#	Line 869 | Line 874 | public class PriorityQueue<E> extends Ab
874		throw new ConcurrentModificationException();
875		}
876
872	–	@SuppressWarnings("unchecked")
877		public boolean tryAdvance(Consumer<? super E> action) {
878		if (action == null)
879		throw new NullPointerException();
#	Line 895 | Line 899 | public class PriorityQueue<E> extends Ab
899		return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
900		}
901		}
902	+
903	+	/**
904	+	* @throws NullPointerException {@inheritDoc}
905	+	*/
906	+	public void forEach(Consumer<? super E> action) {
907	+	Objects.requireNonNull(action);
908	+	final int expectedModCount = modCount;
909	+	final Object[] es = queue;
910	+	for (int i = 0, n = size; i < n; i++)
911	+	action.accept((E) es[i]);
912	+	if (expectedModCount != modCount)
913	+	throw new ConcurrentModificationException();
914	+	}
915		}

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