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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.76 by jsr166, Fri Dec 2 14:37:32 2011 UTC vs.
Revision 1.95 by dl, Wed Mar 27 23:09:35 2013 UTC

# Line 1 | Line 1
1   /*
2 < * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
2 > * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
3   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4   *
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.  Sun designates this
7 > * published by the Free Software Foundation.  Oracle designates this
8   * particular file as subject to the "Classpath" exception as provided
9 < * by Sun in the LICENSE file that accompanied this code.
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
# Line 24 | Line 24
24   */
25  
26   package java.util;
27 + import java.util.function.Consumer;
28 + import java.util.stream.Stream;
29 + import java.util.stream.Streams;
30  
31   /**
32   * An unbounded priority {@linkplain Queue queue} based on a priority heap.
# Line 56 | Line 59 | package java.util;
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
# Line 77 | Line 80 | package java.util;
80   * @author Josh Bloch, Doug Lea
81   * @param <E> the type of elements held in this collection
82   */
80 – @SuppressWarnings("unchecked")
83   public class PriorityQueue<E> extends AbstractQueue<E>
84      implements java.io.Serializable {
85  
# Line 93 | Line 95 | public class PriorityQueue<E> extends Ab
95       * heap and each descendant d of n, n <= d.  The element with the
96       * lowest value is in queue[0], assuming the queue is nonempty.
97       */
98 <    private transient Object[] queue;
98 >    transient Object[] queue; // non-private to simplify nested class access
99  
100      /**
101       * The number of elements in the priority queue.
# Line 110 | Line 112 | public class PriorityQueue<E> extends Ab
112       * The number of times this priority queue has been
113       * <i>structurally modified</i>.  See AbstractList for gory details.
114       */
115 <    private transient int modCount = 0;
115 >    transient int modCount = 0; // non-private to simplify nested class access
116  
117      /**
118       * Creates a {@code PriorityQueue} with the default initial
# Line 331 | Line 333 | public class PriorityQueue<E> extends Ab
333          return true;
334      }
335  
336 +    @SuppressWarnings("unchecked")
337      public E peek() {
338          return (size == 0) ? null : (E) queue[0];
339      }
# Line 429 | Line 432 | public class PriorityQueue<E> extends Ab
432       * precise control over the runtime type of the output array, and may,
433       * under certain circumstances, be used to save allocation costs.
434       *
435 <     * <p>Suppose <tt>x</tt> is a queue known to contain only strings.
435 >     * <p>Suppose {@code x} is a queue known to contain only strings.
436       * The following code can be used to dump the queue into a newly
437 <     * allocated array of <tt>String</tt>:
437 >     * allocated array of {@code String}:
438       *
439       *  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
440       *
441 <     * Note that <tt>toArray(new Object[0])</tt> is identical in function to
442 <     * <tt>toArray()</tt>.
441 >     * Note that {@code toArray(new Object[0])} is identical in function to
442 >     * {@code toArray()}.
443       *
444       * @param a the array into which the elements of the queue are to
445       *          be stored, if it is big enough; otherwise, a new array of the
# Line 447 | Line 450 | public class PriorityQueue<E> extends Ab
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());
# Line 512 | Line 517 | public class PriorityQueue<E> extends Ab
517                  (forgetMeNot != null && !forgetMeNot.isEmpty());
518          }
519  
520 +        @SuppressWarnings("unchecked")
521          public E next() {
522              if (expectedModCount != modCount)
523                  throw new ConcurrentModificationException();
# Line 536 | Line 542 | public class PriorityQueue<E> extends Ab
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) {
# Line 564 | Line 570 | public class PriorityQueue<E> extends Ab
570          size = 0;
571      }
572  
573 +    @SuppressWarnings("unchecked")
574      public E poll() {
575          if (size == 0)
576              return null;
# Line 589 | Line 596 | public class PriorityQueue<E> extends Ab
596       * position before i. This fact is used by iterator.remove so as to
597       * avoid missing traversing elements.
598       */
599 +    @SuppressWarnings("unchecked")
600      private E removeAt(int i) {
601          // assert i >= 0 && i < size;
602          modCount++;
# Line 627 | Line 635 | public class PriorityQueue<E> extends Ab
635              siftUpComparable(k, x);
636      }
637  
638 +    @SuppressWarnings("unchecked")
639      private void siftUpComparable(int k, E x) {
640          Comparable<? super E> key = (Comparable<? super E>) x;
641          while (k > 0) {
# Line 640 | Line 649 | public class PriorityQueue<E> extends Ab
649          queue[k] = key;
650      }
651  
652 +    @SuppressWarnings("unchecked")
653      private void siftUpUsingComparator(int k, E x) {
654          while (k > 0) {
655              int parent = (k - 1) >>> 1;
# Line 667 | Line 677 | public class PriorityQueue<E> extends Ab
677              siftDownComparable(k, x);
678      }
679  
680 +    @SuppressWarnings("unchecked")
681      private void siftDownComparable(int k, E x) {
682          Comparable<? super E> key = (Comparable<? super E>)x;
683          int half = size >>> 1;        // loop while a non-leaf
# Line 685 | Line 696 | public class PriorityQueue<E> extends Ab
696          queue[k] = key;
697      }
698  
699 +    @SuppressWarnings("unchecked")
700      private void siftDownUsingComparator(int k, E x) {
701          int half = size >>> 1;
702          while (k < half) {
# Line 706 | Line 718 | public class PriorityQueue<E> extends Ab
718       * Establishes the heap invariant (described above) in the entire tree,
719       * assuming nothing about the order of the elements prior to the call.
720       */
721 +    @SuppressWarnings("unchecked")
722      private void heapify() {
723          for (int i = (size >>> 1) - 1; i >= 0; i--)
724              siftDown(i, (E) queue[i]);
# Line 725 | Line 738 | public class PriorityQueue<E> extends Ab
738      }
739  
740      /**
741 <     * Saves the state of the instance to a stream (that
729 <     * is, serializes it).
741 >     * Saves this queue to a stream (that is, serializes it).
742       *
743       * @serialData The length of the array backing the instance is
744       *             emitted (int), followed by all of its elements
# Line 770 | Line 782 | public class PriorityQueue<E> extends Ab
782          // spec has never explained what that might be.
783          heapify();
784      }
785 +
786 +    public Spliterator<E> spliterator() {
787 +        return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
788 +    }
789 +
790 +    /**
791 +     * This is very similar to ArrayList Spliterator, except for extra
792 +     * null checks.
793 +     */
794 +    static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
795 +        private final PriorityQueue<E> pq;
796 +        private int index;            // current index, modified on advance/split
797 +        private int fence;            // -1 until first use
798 +        private int expectedModCount; // initialized when fence set
799 +
800 +        /** Creates new spliterator covering the given range */
801 +        PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
802 +                             int expectedModCount) {
803 +            this.pq = pq;
804 +            this.index = origin;
805 +            this.fence = fence;
806 +            this.expectedModCount = expectedModCount;
807 +        }
808 +
809 +        private int getFence() { // initialize fence to size on first use
810 +            int hi;
811 +            if ((hi = fence) < 0) {
812 +                expectedModCount = pq.modCount;
813 +                hi = fence = pq.size;
814 +            }
815 +            return hi;
816 +        }
817 +
818 +        public Spliterator<E> trySplit() {
819 +            int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
820 +            return (lo >= mid) ? null :
821 +                new PriorityQueueSpliterator<E>(pq, lo, index = mid,
822 +                                                expectedModCount);
823 +        }
824 +
825 +        @SuppressWarnings("unchecked")
826 +        public void forEachRemaining(Consumer<? super E> action) {
827 +            int i, hi, mc; // hoist accesses and checks from loop
828 +            PriorityQueue<E> q; Object[] a;
829 +            if (action == null)
830 +                throw new NullPointerException();
831 +            if ((q = pq) != null && (a = q.queue) != null) {
832 +                if ((hi = fence) < 0) {
833 +                    mc = q.modCount;
834 +                    hi = q.size;
835 +                }
836 +                else
837 +                    mc = expectedModCount;
838 +                if ((i = index) >= 0 && (index = hi) <= a.length) {
839 +                    for (E e;; ++i) {
840 +                        if (i < hi) {
841 +                            if ((e = (E) a[i]) == null) // must be CME
842 +                                break;
843 +                            action.accept(e);
844 +                        }
845 +                        else if (q.modCount != mc)
846 +                            break;
847 +                        else
848 +                            return;
849 +                    }
850 +                }
851 +            }
852 +            throw new ConcurrentModificationException();
853 +        }
854 +
855 +        public boolean tryAdvance(Consumer<? super E> action) {
856 +            int hi = getFence(), lo = index;
857 +            if (lo >= 0 && lo < hi) {
858 +                index = lo + 1;
859 +                @SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
860 +                if (e == null)
861 +                    throw new ConcurrentModificationException();
862 +                action.accept(e);
863 +                if (pq.modCount != expectedModCount)
864 +                    throw new ConcurrentModificationException();
865 +                return true;
866 +            }
867 +            return false;
868 +        }
869 +
870 +        public long estimateSize() {
871 +            return (long) (getFence() - index);
872 +        }
873 +
874 +        public int characteristics() {
875 +            return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
876 +        }
877 +    }
878   }

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