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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.73 by jsr166, Tue Jun 21 19:29:21 2011 UTC vs.
Revision 1.96 by jsr166, Thu May 2 06:02:17 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  
30   /**
31   * An unbounded priority {@linkplain Queue queue} based on a priority heap.
# Line 56 | Line 58 | package java.util;
58   * the priority queue in any particular order. If you need ordered
59   * traversal, consider using {@code Arrays.sort(pq.toArray())}.
60   *
61 < * <p> <strong>Note that this implementation is not synchronized.</strong>
61 > * <p><strong>Note that this implementation is not synchronized.</strong>
62   * Multiple threads should not access a {@code PriorityQueue}
63   * instance concurrently if any of the threads modifies the queue.
64   * Instead, use the thread-safe {@link
# Line 92 | Line 94 | public class PriorityQueue<E> extends Ab
94       * heap and each descendant d of n, n <= d.  The element with the
95       * lowest value is in queue[0], assuming the queue is nonempty.
96       */
97 <    private transient Object[] queue;
97 >    transient Object[] queue; // non-private to simplify nested class access
98  
99      /**
100       * The number of elements in the priority queue.
# Line 109 | Line 111 | public class PriorityQueue<E> extends Ab
111       * The number of times this priority queue has been
112       * <i>structurally modified</i>.  See AbstractList for gory details.
113       */
114 <    private transient int modCount = 0;
114 >    transient int modCount = 0; // non-private to simplify nested class access
115  
116      /**
117       * Creates a {@code PriorityQueue} with the default initial
# Line 330 | Line 332 | public class PriorityQueue<E> extends Ab
332          return true;
333      }
334  
335 +    @SuppressWarnings("unchecked")
336      public E peek() {
337          return (size == 0) ? null : (E) queue[0];
338      }
# Line 428 | Line 431 | public class PriorityQueue<E> extends Ab
431       * precise control over the runtime type of the output array, and may,
432       * under certain circumstances, be used to save allocation costs.
433       *
434 <     * <p>Suppose <tt>x</tt> is a queue known to contain only strings.
434 >     * <p>Suppose {@code x} is a queue known to contain only strings.
435       * The following code can be used to dump the queue into a newly
436 <     * allocated array of <tt>String</tt>:
436 >     * allocated array of {@code String}:
437       *
438       *  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
439       *
440 <     * Note that <tt>toArray(new Object[0])</tt> is identical in function to
441 <     * <tt>toArray()</tt>.
440 >     * Note that {@code toArray(new Object[0])} is identical in function to
441 >     * {@code toArray()}.
442       *
443       * @param a the array into which the elements of the queue are to
444       *          be stored, if it is big enough; otherwise, a new array of the
# Line 446 | Line 449 | public class PriorityQueue<E> extends Ab
449       *         this queue
450       * @throws NullPointerException if the specified array is null
451       */
452 +    @SuppressWarnings("unchecked")
453      public <T> T[] toArray(T[] a) {
454 +        final int size = this.size;
455          if (a.length < size)
456              // Make a new array of a's runtime type, but my contents:
457              return (T[]) Arrays.copyOf(queue, size, a.getClass());
# Line 511 | Line 516 | public class PriorityQueue<E> extends Ab
516                  (forgetMeNot != null && !forgetMeNot.isEmpty());
517          }
518  
519 +        @SuppressWarnings("unchecked")
520          public E next() {
521              if (expectedModCount != modCount)
522                  throw new ConcurrentModificationException();
# Line 535 | Line 541 | public class PriorityQueue<E> extends Ab
541                      cursor--;
542                  else {
543                      if (forgetMeNot == null)
544 <                        forgetMeNot = new ArrayDeque<E>();
544 >                        forgetMeNot = new ArrayDeque<>();
545                      forgetMeNot.add(moved);
546                  }
547              } else if (lastRetElt != null) {
# Line 563 | Line 569 | public class PriorityQueue<E> extends Ab
569          size = 0;
570      }
571  
572 +    @SuppressWarnings("unchecked")
573      public E poll() {
574          if (size == 0)
575              return null;
# Line 588 | Line 595 | public class PriorityQueue<E> extends Ab
595       * position before i. This fact is used by iterator.remove so as to
596       * avoid missing traversing elements.
597       */
598 +    @SuppressWarnings("unchecked")
599      private E removeAt(int i) {
600 <        assert i >= 0 && i < size;
600 >        // assert i >= 0 && i < size;
601          modCount++;
602          int s = --size;
603          if (s == i) // removed last element
# Line 626 | Line 634 | public class PriorityQueue<E> extends Ab
634              siftUpComparable(k, x);
635      }
636  
637 +    @SuppressWarnings("unchecked")
638      private void siftUpComparable(int k, E x) {
639          Comparable<? super E> key = (Comparable<? super E>) x;
640          while (k > 0) {
# Line 639 | Line 648 | public class PriorityQueue<E> extends Ab
648          queue[k] = key;
649      }
650  
651 +    @SuppressWarnings("unchecked")
652      private void siftUpUsingComparator(int k, E x) {
653          while (k > 0) {
654              int parent = (k - 1) >>> 1;
# Line 666 | Line 676 | public class PriorityQueue<E> extends Ab
676              siftDownComparable(k, x);
677      }
678  
679 +    @SuppressWarnings("unchecked")
680      private void siftDownComparable(int k, E x) {
681          Comparable<? super E> key = (Comparable<? super E>)x;
682          int half = size >>> 1;        // loop while a non-leaf
# Line 684 | Line 695 | public class PriorityQueue<E> extends Ab
695          queue[k] = key;
696      }
697  
698 +    @SuppressWarnings("unchecked")
699      private void siftDownUsingComparator(int k, E x) {
700          int half = size >>> 1;
701          while (k < half) {
# Line 705 | Line 717 | public class PriorityQueue<E> extends Ab
717       * Establishes the heap invariant (described above) in the entire tree,
718       * assuming nothing about the order of the elements prior to the call.
719       */
720 +    @SuppressWarnings("unchecked")
721      private void heapify() {
722          for (int i = (size >>> 1) - 1; i >= 0; i--)
723              siftDown(i, (E) queue[i]);
# Line 724 | Line 737 | public class PriorityQueue<E> extends Ab
737      }
738  
739      /**
740 <     * Saves the state of the instance to a stream (that
728 <     * is, serializes it).
740 >     * Saves this queue to a stream (that is, serializes it).
741       *
742       * @serialData The length of the array backing the instance is
743       *             emitted (int), followed by all of its elements
# Line 733 | Line 745 | public class PriorityQueue<E> extends Ab
745       * @param s the stream
746       */
747      private void writeObject(java.io.ObjectOutputStream s)
748 <        throws java.io.IOException{
748 >        throws java.io.IOException {
749          // Write out element count, and any hidden stuff
750          s.defaultWriteObject();
751  
# Line 769 | Line 781 | public class PriorityQueue<E> extends Ab
781          // spec has never explained what that might be.
782          heapify();
783      }
784 +
785 +    public Spliterator<E> spliterator() {
786 +        return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
787 +    }
788 +
789 +    /**
790 +     * This is very similar to ArrayList Spliterator, except for extra
791 +     * null checks.
792 +     */
793 +    static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
794 +        private final PriorityQueue<E> pq;
795 +        private int index;            // current index, modified on advance/split
796 +        private int fence;            // -1 until first use
797 +        private int expectedModCount; // initialized when fence set
798 +
799 +        /** Creates new spliterator covering the given range */
800 +        PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
801 +                             int expectedModCount) {
802 +            this.pq = pq;
803 +            this.index = origin;
804 +            this.fence = fence;
805 +            this.expectedModCount = expectedModCount;
806 +        }
807 +
808 +        private int getFence() { // initialize fence to size on first use
809 +            int hi;
810 +            if ((hi = fence) < 0) {
811 +                expectedModCount = pq.modCount;
812 +                hi = fence = pq.size;
813 +            }
814 +            return hi;
815 +        }
816 +
817 +        public Spliterator<E> trySplit() {
818 +            int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
819 +            return (lo >= mid) ? null :
820 +                new PriorityQueueSpliterator<E>(pq, lo, index = mid,
821 +                                                expectedModCount);
822 +        }
823 +
824 +        @SuppressWarnings("unchecked")
825 +        public void forEachRemaining(Consumer<? super E> action) {
826 +            int i, hi, mc; // hoist accesses and checks from loop
827 +            PriorityQueue<E> q; Object[] a;
828 +            if (action == null)
829 +                throw new NullPointerException();
830 +            if ((q = pq) != null && (a = q.queue) != null) {
831 +                if ((hi = fence) < 0) {
832 +                    mc = q.modCount;
833 +                    hi = q.size;
834 +                }
835 +                else
836 +                    mc = expectedModCount;
837 +                if ((i = index) >= 0 && (index = hi) <= a.length) {
838 +                    for (E e;; ++i) {
839 +                        if (i < hi) {
840 +                            if ((e = (E) a[i]) == null) // must be CME
841 +                                break;
842 +                            action.accept(e);
843 +                        }
844 +                        else if (q.modCount != mc)
845 +                            break;
846 +                        else
847 +                            return;
848 +                    }
849 +                }
850 +            }
851 +            throw new ConcurrentModificationException();
852 +        }
853 +
854 +        public boolean tryAdvance(Consumer<? super E> action) {
855 +            int hi = getFence(), lo = index;
856 +            if (lo >= 0 && lo < hi) {
857 +                index = lo + 1;
858 +                @SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
859 +                if (e == null)
860 +                    throw new ConcurrentModificationException();
861 +                action.accept(e);
862 +                if (pq.modCount != expectedModCount)
863 +                    throw new ConcurrentModificationException();
864 +                return true;
865 +            }
866 +            return false;
867 +        }
868 +
869 +        public long estimateSize() {
870 +            return (long) (getFence() - index);
871 +        }
872 +
873 +        public int characteristics() {
874 +            return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
875 +        }
876 +    }
877   }

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