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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 1.83 by jsr166, Sat Jan 19 17:33:55 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.stream.Stream;
28 + import java.util.Spliterator;
29 + import java.util.stream.Streams;
30 + import java.util.function.Block;
31  
32   /**
33   * An unbounded priority {@linkplain Queue queue} based on a priority heap.
# Line 56 | Line 60 | package java.util;
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
# Line 92 | Line 96 | public class PriorityQueue<E> extends Ab
96       * heap and each descendant d of n, n <= d.  The element with the
97       * lowest value is in queue[0], assuming the queue is nonempty.
98       */
99 <    private transient Object[] queue;
99 >    transient Object[] queue; // non-private to simplify nested class access
100  
101      /**
102       * The number of elements in the priority queue.
# Line 109 | Line 113 | public class PriorityQueue<E> extends Ab
113       * The number of times this priority queue has been
114       * <i>structurally modified</i>.  See AbstractList for gory details.
115       */
116 <    private transient int modCount = 0;
116 >    transient int modCount = 0; // non-private to simplify nested class access
117  
118      /**
119       * Creates a {@code PriorityQueue} with the default initial
# Line 330 | Line 334 | public class PriorityQueue<E> extends Ab
334          return true;
335      }
336  
337 +    @SuppressWarnings("unchecked")
338      public E peek() {
339          return (size == 0) ? null : (E) queue[0];
340      }
# Line 428 | Line 433 | public class PriorityQueue<E> extends Ab
433       * precise control over the runtime type of the output array, and may,
434       * under certain circumstances, be used to save allocation costs.
435       *
436 <     * <p>Suppose <tt>x</tt> is a queue known to contain only strings.
436 >     * <p>Suppose {@code x} is a queue known to contain only strings.
437       * The following code can be used to dump the queue into a newly
438 <     * allocated array of <tt>String</tt>:
438 >     * allocated array of {@code String}:
439       *
440       *  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
441       *
442 <     * Note that <tt>toArray(new Object[0])</tt> is identical in function to
443 <     * <tt>toArray()</tt>.
442 >     * Note that {@code toArray(new Object[0])} is identical in function to
443 >     * {@code toArray()}.
444       *
445       * @param a the array into which the elements of the queue are to
446       *          be stored, if it is big enough; otherwise, a new array of the
# 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 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 +    // wrapping constructor in method avoids transient javac problems
786 +    final PriorityQueueSpliterator<E> spliterator(int origin, int fence,
787 +                                                  int expectedModCount) {
788 +        return new PriorityQueueSpliterator<E>(this, origin, fence,
789 +                                               expectedModCount);
790 +    }
791 +
792 +    public Stream<E> stream() {
793 +        int flags = Streams.STREAM_IS_SIZED;
794 +        return Streams.stream
795 +            (() -> spliterator(0, size, modCount), flags);
796 +    }
797 +    public Stream<E> parallelStream() {
798 +        int flags = Streams.STREAM_IS_SIZED;
799 +        return Streams.parallelStream
800 +            (() -> spliterator(0, size, modCount), flags);
801 +    }
802 +
803 +    /** Index-based split-by-two Spliterator */
804 +    static final class PriorityQueueSpliterator<E>
805 +        implements Spliterator<E>, Iterator<E> {
806 +        private final PriorityQueue<E> pq;
807 +        private int index;           // current index, modified on advance/split
808 +        private final int fence;     // one past last index
809 +        private final int expectedModCount; // for comodification checks
810 +
811 +        /** Create new spliterator covering the given  range */
812 +        PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
813 +                             int expectedModCount) {
814 +            this.pq = pq; this.index = origin; this.fence = fence;
815 +            this.expectedModCount = expectedModCount;
816 +        }
817 +
818 +        public PriorityQueueSpliterator<E> trySplit() {
819 +            int lo = index, mid = (lo + fence) >>> 1;
820 +            return (lo >= mid) ? null :
821 +                new PriorityQueueSpliterator<E>(pq, lo, index = mid,
822 +                                            expectedModCount);
823 +        }
824 +
825 +        public void forEach(Block<? super E> block) {
826 +            Object[] a; int i, hi; // hoist accesses and checks from loop
827 +            if (block == null)
828 +                throw new NullPointerException();
829 +            if ((a = pq.queue).length >= (hi = fence) &&
830 +                (i = index) >= 0 && i < hi) {
831 +                index = hi;
832 +                do {
833 +                    @SuppressWarnings("unchecked") E e = (E) a[i];
834 +                    block.accept(e);
835 +                } while (++i < hi);
836 +                if (pq.modCount != expectedModCount)
837 +                    throw new ConcurrentModificationException();
838 +            }
839 +        }
840 +
841 +        public boolean tryAdvance(Block<? super E> block) {
842 +            if (index >= 0 && index < fence) {
843 +                if (pq.modCount != expectedModCount)
844 +                    throw new ConcurrentModificationException();
845 +                @SuppressWarnings("unchecked") E e =
846 +                    (E)pq.queue[index++];
847 +                block.accept(e);
848 +                return true;
849 +            }
850 +            return false;
851 +        }
852 +
853 +        public long estimateSize() { return (long)(fence - index); }
854 +        public boolean hasExactSize() { return true; }
855 +        public boolean hasExactSplits() { return true; }
856 +
857 +        // Iterator support
858 +        public Iterator<E> iterator() { return this; }
859 +        public void remove() { throw new UnsupportedOperationException(); }
860 +        public boolean hasNext() { return index >= 0 && index < fence; }
861 +
862 +        public E next() {
863 +            if (index < 0 || index >= fence)
864 +                throw new NoSuchElementException();
865 +            if (pq.modCount != expectedModCount)
866 +                throw new ConcurrentModificationException();
867 +            @SuppressWarnings("unchecked") E e =
868 +                (E) pq.queue[index++];
869 +            return e;
870 +        }
871 +    }
872   }

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