--- jsr166/src/main/java/util/PriorityQueue.java	2008/05/18 23:47:56	1.68
+++ jsr166/src/main/java/util/PriorityQueue.java	2011/06/10 00:20:44	1.72
@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright (c) 2003, 2006, 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
@@ -18,9 +18,9 @@
  * 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;
@@ -74,7 +74,6 @@ package java.util;
  * Java Collections Framework</a>.
  *
  * @since 1.5
- * @version %I%, %G%
  * @author Josh Bloch, Doug Lea
  * @param <E> the type of elements held in this collection
  */
@@ -171,17 +170,21 @@ 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);
         }
     }
 
@@ -199,9 +202,10 @@ 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);
     }
 
     /**
@@ -217,9 +221,33 @@ 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;
     }
 
     /**
@@ -228,34 +256,43 @@ 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.
      *
@@ -397,8 +434,7 @@ public class PriorityQueue<E> extends Ab
      * The following code can be used to dump the queue into a newly
      * allocated array of <tt>String</tt>:
      *
-     * <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>.