--- jsr166/src/main/java/util/PriorityQueue.java	2008/05/18 23:59:57	1.69
+++ jsr166/src/main/java/util/PriorityQueue.java	2013/07/18 18:21:22	1.97
@@ -1,12 +1,12 @@
 /*
- * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Sun designates this
+ * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
- * by Sun in the LICENSE file that accompanied this code.
+ * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
@@ -18,12 +18,14 @@
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
  */
 
 package java.util;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
 
 /**
  * An unbounded priority {@linkplain Queue queue} based on a priority heap.
@@ -56,7 +58,7 @@ package java.util;
  * the priority queue in any particular order. If you need ordered
  * traversal, consider using {@code Arrays.sort(pq.toArray())}.
  *
- * <p> <strong>Note that this implementation is not synchronized.</strong>
+ * <p><strong>Note that this implementation is not synchronized.</strong>
  * Multiple threads should not access a {@code PriorityQueue}
  * instance concurrently if any of the threads modifies the queue.
  * Instead, use the thread-safe {@link
@@ -92,7 +94,7 @@ public class PriorityQueue<E> extends Ab
      * heap and each descendant d of n, n <= d.  The element with the
      * lowest value is in queue[0], assuming the queue is nonempty.
      */
-    private transient Object[] queue;
+    transient Object[] queue; // non-private to simplify nested class access
 
     /**
      * The number of elements in the priority queue.
@@ -109,7 +111,7 @@ public class PriorityQueue<E> extends Ab
      * The number of times this priority queue has been
      * <i>structurally modified</i>.  See AbstractList for gory details.
      */
-    private transient int modCount = 0;
+    transient int modCount = 0; // non-private to simplify nested class access
 
     /**
      * Creates a {@code PriorityQueue} with the default initial
@@ -170,17 +172,21 @@ public class PriorityQueue<E> extends Ab
      * @throws NullPointerException if the specified collection or any
      *         of its elements are null
      */
+    @SuppressWarnings("unchecked")
     public PriorityQueue(Collection<? extends E> c) {
-        initFromCollection(c);
-        if (c instanceof SortedSet)
-            comparator = (Comparator<? super E>)
-                ((SortedSet<? extends E>)c).comparator();
-        else if (c instanceof PriorityQueue)
-            comparator = (Comparator<? super E>)
-                ((PriorityQueue<? extends E>)c).comparator();
+        if (c instanceof SortedSet<?>) {
+            SortedSet<? extends E> ss = (SortedSet<? extends E>) c;
+            this.comparator = (Comparator<? super E>) ss.comparator();
+            initElementsFromCollection(ss);
+        }
+        else if (c instanceof PriorityQueue<?>) {
+            PriorityQueue<? extends E> pq = (PriorityQueue<? extends E>) c;
+            this.comparator = (Comparator<? super E>) pq.comparator();
+            initFromPriorityQueue(pq);
+        }
         else {
-            comparator = null;
-            heapify();
+            this.comparator = null;
+            initFromCollection(c);
         }
     }
 
@@ -198,9 +204,10 @@ public class PriorityQueue<E> extends Ab
      * @throws NullPointerException if the specified priority queue or any
      *         of its elements are null
      */
+    @SuppressWarnings("unchecked")
     public PriorityQueue(PriorityQueue<? extends E> c) {
-        comparator = (Comparator<? super E>)c.comparator();
-        initFromCollection(c);
+        this.comparator = (Comparator<? super E>) c.comparator();
+        initFromPriorityQueue(c);
     }
 
     /**
@@ -216,9 +223,33 @@ public class PriorityQueue<E> extends Ab
      * @throws NullPointerException if the specified sorted set or any
      *         of its elements are null
      */
+    @SuppressWarnings("unchecked")
     public PriorityQueue(SortedSet<? extends E> c) {
-        comparator = (Comparator<? super E>)c.comparator();
-        initFromCollection(c);
+        this.comparator = (Comparator<? super E>) c.comparator();
+        initElementsFromCollection(c);
+    }
+
+    private void initFromPriorityQueue(PriorityQueue<? extends E> c) {
+        if (c.getClass() == PriorityQueue.class) {
+            this.queue = c.toArray();
+            this.size = c.size();
+        } else {
+            initFromCollection(c);
+        }
+    }
+
+    private void initElementsFromCollection(Collection<? extends E> c) {
+        Object[] a = c.toArray();
+        // If c.toArray incorrectly doesn't return Object[], copy it.
+        if (a.getClass() != Object[].class)
+            a = Arrays.copyOf(a, a.length, Object[].class);
+        int len = a.length;
+        if (len == 1 || this.comparator != null)
+            for (int i = 0; i < len; i++)
+                if (a[i] == null)
+                    throw new NullPointerException();
+        this.queue = a;
+        this.size = a.length;
     }
 
     /**
@@ -227,34 +258,43 @@ public class PriorityQueue<E> extends Ab
      * @param c the collection
      */
     private void initFromCollection(Collection<? extends E> c) {
-        Object[] a = c.toArray();
-        // If c.toArray incorrectly doesn't return Object[], copy it.
-        if (a.getClass() != Object[].class)
-            a = Arrays.copyOf(a, a.length, Object[].class);
-        queue = a;
-        size = a.length;
+        initElementsFromCollection(c);
+        heapify();
     }
 
     /**
+     * The maximum size of array to allocate.
+     * Some VMs reserve some header words in an array.
+     * Attempts to allocate larger arrays may result in
+     * OutOfMemoryError: Requested array size exceeds VM limit
+     */
+    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
+
+    /**
      * Increases the capacity of the array.
      *
      * @param minCapacity the desired minimum capacity
      */
     private void grow(int minCapacity) {
-        if (minCapacity < 0) // overflow
-            throw new OutOfMemoryError();
         int oldCapacity = queue.length;
         // Double size if small; else grow by 50%
-        int newCapacity = ((oldCapacity < 64)?
-                           ((oldCapacity + 1) * 2):
-                           ((oldCapacity / 2) * 3));
-        if (newCapacity < 0) // overflow
-            newCapacity = Integer.MAX_VALUE;
-        if (newCapacity < minCapacity)
-            newCapacity = minCapacity;
+        int newCapacity = oldCapacity + ((oldCapacity < 64) ?
+                                         (oldCapacity + 2) :
+                                         (oldCapacity >> 1));
+        // overflow-conscious code
+        if (newCapacity - MAX_ARRAY_SIZE > 0)
+            newCapacity = hugeCapacity(minCapacity);
         queue = Arrays.copyOf(queue, newCapacity);
     }
 
+    private static int hugeCapacity(int minCapacity) {
+        if (minCapacity < 0) // overflow
+            throw new OutOfMemoryError();
+        return (minCapacity > MAX_ARRAY_SIZE) ?
+            Integer.MAX_VALUE :
+            MAX_ARRAY_SIZE;
+    }
+
     /**
      * Inserts the specified element into this priority queue.
      *
@@ -292,10 +332,9 @@ public class PriorityQueue<E> extends Ab
         return true;
     }
 
+    @SuppressWarnings("unchecked")
     public E peek() {
-        if (size == 0)
-            return null;
-        return (E) queue[0];
+        return (size == 0) ? null : (E) queue[0];
     }
 
     private int indexOf(Object o) {
@@ -392,15 +431,14 @@ public class PriorityQueue<E> extends Ab
      * precise control over the runtime type of the output array, and may,
      * under certain circumstances, be used to save allocation costs.
      *
-     * <p>Suppose <tt>x</tt> is a queue known to contain only strings.
+     * <p>Suppose {@code x} is a queue known to contain only strings.
      * The following code can be used to dump the queue into a newly
-     * allocated array of <tt>String</tt>:
+     * allocated array of {@code String}:
      *
-     * <pre>
-     *     String[] y = x.toArray(new String[0]);</pre>
+     *  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
      *
-     * Note that <tt>toArray(new Object[0])</tt> is identical in function to
-     * <tt>toArray()</tt>.
+     * Note that {@code toArray(new Object[0])} is identical in function to
+     * {@code toArray()}.
      *
      * @param a the array into which the elements of the queue are to
      *          be stored, if it is big enough; otherwise, a new array of the
@@ -411,7 +449,9 @@ public class PriorityQueue<E> extends Ab
      *         this queue
      * @throws NullPointerException if the specified array is null
      */
+    @SuppressWarnings("unchecked")
     public <T> T[] toArray(T[] a) {
+        final int size = this.size;
         if (a.length < size)
             // Make a new array of a's runtime type, but my contents:
             return (T[]) Arrays.copyOf(queue, size, a.getClass());
@@ -476,6 +516,7 @@ public class PriorityQueue<E> extends Ab
                 (forgetMeNot != null && !forgetMeNot.isEmpty());
         }
 
+        @SuppressWarnings("unchecked")
         public E next() {
             if (expectedModCount != modCount)
                 throw new ConcurrentModificationException();
@@ -500,7 +541,7 @@ public class PriorityQueue<E> extends Ab
                     cursor--;
                 else {
                     if (forgetMeNot == null)
-                        forgetMeNot = new ArrayDeque<E>();
+                        forgetMeNot = new ArrayDeque<>();
                     forgetMeNot.add(moved);
                 }
             } else if (lastRetElt != null) {
@@ -528,6 +569,7 @@ public class PriorityQueue<E> extends Ab
         size = 0;
     }
 
+    @SuppressWarnings("unchecked")
     public E poll() {
         if (size == 0)
             return null;
@@ -553,8 +595,9 @@ public class PriorityQueue<E> extends Ab
      * position before i. This fact is used by iterator.remove so as to
      * avoid missing traversing elements.
      */
+    @SuppressWarnings("unchecked")
     private E removeAt(int i) {
-        assert i >= 0 && i < size;
+        // assert i >= 0 && i < size;
         modCount++;
         int s = --size;
         if (s == i) // removed last element
@@ -591,6 +634,7 @@ public class PriorityQueue<E> extends Ab
             siftUpComparable(k, x);
     }
 
+    @SuppressWarnings("unchecked")
     private void siftUpComparable(int k, E x) {
         Comparable<? super E> key = (Comparable<? super E>) x;
         while (k > 0) {
@@ -604,6 +648,7 @@ public class PriorityQueue<E> extends Ab
         queue[k] = key;
     }
 
+    @SuppressWarnings("unchecked")
     private void siftUpUsingComparator(int k, E x) {
         while (k > 0) {
             int parent = (k - 1) >>> 1;
@@ -631,6 +676,7 @@ public class PriorityQueue<E> extends Ab
             siftDownComparable(k, x);
     }
 
+    @SuppressWarnings("unchecked")
     private void siftDownComparable(int k, E x) {
         Comparable<? super E> key = (Comparable<? super E>)x;
         int half = size >>> 1;        // loop while a non-leaf
@@ -649,6 +695,7 @@ public class PriorityQueue<E> extends Ab
         queue[k] = key;
     }
 
+    @SuppressWarnings("unchecked")
     private void siftDownUsingComparator(int k, E x) {
         int half = size >>> 1;
         while (k < half) {
@@ -670,6 +717,7 @@ public class PriorityQueue<E> extends Ab
      * Establishes the heap invariant (described above) in the entire tree,
      * assuming nothing about the order of the elements prior to the call.
      */
+    @SuppressWarnings("unchecked")
     private void heapify() {
         for (int i = (size >>> 1) - 1; i >= 0; i--)
             siftDown(i, (E) queue[i]);
@@ -689,16 +737,16 @@ public class PriorityQueue<E> extends Ab
     }
 
     /**
-     * Saves the state of the instance to a stream (that
-     * is, serializes it).
+     * Saves this queue to a stream (that is, serializes it).
      *
      * @serialData The length of the array backing the instance is
      *             emitted (int), followed by all of its elements
      *             (each an {@code Object}) in the proper order.
      * @param s the stream
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void writeObject(java.io.ObjectOutputStream s)
-        throws java.io.IOException{
+        throws java.io.IOException {
         // Write out element count, and any hidden stuff
         s.defaultWriteObject();
 
@@ -715,6 +763,9 @@ public class PriorityQueue<E> extends Ab
      * (that is, deserializes it).
      *
      * @param s the stream
+     * @throws ClassNotFoundException if the class of a serialized object
+     *         could not be found
+     * @throws java.io.IOException if an I/O error occurs
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
@@ -734,4 +785,97 @@ public class PriorityQueue<E> extends Ab
         // spec has never explained what that might be.
         heapify();
     }
+
+    public Spliterator<E> spliterator() {
+        return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
+    }
+
+    /**
+     * This is very similar to ArrayList Spliterator, except for extra
+     * null checks.
+     */
+    static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
+        private final PriorityQueue<E> pq;
+        private int index;            // current index, modified on advance/split
+        private int fence;            // -1 until first use
+        private int expectedModCount; // initialized when fence set
+
+        /** Creates new spliterator covering the given range */
+        PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
+                             int expectedModCount) {
+            this.pq = pq;
+            this.index = origin;
+            this.fence = fence;
+            this.expectedModCount = expectedModCount;
+        }
+
+        private int getFence() { // initialize fence to size on first use
+            int hi;
+            if ((hi = fence) < 0) {
+                expectedModCount = pq.modCount;
+                hi = fence = pq.size;
+            }
+            return hi;
+        }
+
+        public Spliterator<E> trySplit() {
+            int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
+            return (lo >= mid) ? null :
+                new PriorityQueueSpliterator<E>(pq, lo, index = mid,
+                                                expectedModCount);
+        }
+
+        @SuppressWarnings("unchecked")
+        public void forEachRemaining(Consumer<? super E> action) {
+            int i, hi, mc; // hoist accesses and checks from loop
+            PriorityQueue<E> q; Object[] a;
+            if (action == null)
+                throw new NullPointerException();
+            if ((q = pq) != null && (a = q.queue) != null) {
+                if ((hi = fence) < 0) {
+                    mc = q.modCount;
+                    hi = q.size;
+                }
+                else
+                    mc = expectedModCount;
+                if ((i = index) >= 0 && (index = hi) <= a.length) {
+                    for (E e;; ++i) {
+                        if (i < hi) {
+                            if ((e = (E) a[i]) == null) // must be CME
+                                break;
+                            action.accept(e);
+                        }
+                        else if (q.modCount != mc)
+                            break;
+                        else
+                            return;
+                    }
+                }
+            }
+            throw new ConcurrentModificationException();
+        }
+
+        public boolean tryAdvance(Consumer<? super E> action) {
+            int hi = getFence(), lo = index;
+            if (lo >= 0 && lo < hi) {
+                index = lo + 1;
+                @SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
+                if (e == null)
+                    throw new ConcurrentModificationException();
+                action.accept(e);
+                if (pq.modCount != expectedModCount)
+                    throw new ConcurrentModificationException();
+                return true;
+            }
+            return false;
+        }
+
+        public long estimateSize() {
+            return (long) (getFence() - index);
+        }
+
+        public int characteristics() {
+            return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
+        }
+    }
 }