--- jsr166/src/main/java/util/PriorityQueue.java 2003/07/01 16:29:45 1.8
+++ jsr166/src/main/java/util/PriorityQueue.java 2003/09/01 12:23:28 1.38
@@ -1,38 +1,68 @@
- package java.util;
+/*
+ * %W% %E%
+ *
+ * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
+ * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ */
+
+package java.util;
/**
- * An unbounded priority queue based on a priority heap. This queue orders
- * elements according to an order specified at construction time, which is
- * specified in the same manner as {@link TreeSet} and {@link TreeMap}: elements are ordered
- * either according to their natural order (see {@link Comparable}), or
- * according to a {@link Comparator}, depending on which constructor is used.
- * The {@link #peek}, {@link #poll}, and {@link #remove} methods return the
- * minimal element with respect to the specified ordering. If multiple
- * elements are tied for least value, no guarantees are made as to
- * which of these elements is returned.
+ * An unbounded priority {@linkplain Queue queue} based on a priority heap.
+ * This queue orders elements according to an order specified at construction
+ * time, which is specified in the same manner as {@link java.util.TreeSet}
+ * and {@link java.util.TreeMap}: elements are ordered either according to
+ * their natural order (see {@link Comparable}), or according to a
+ * {@link java.util.Comparator}, depending on which constructor is used.
+ * The head of this queue is the least element with
+ * respect to the specified ordering. If multiple elements are tied for least
+ * value, the head is one of those elements. A priority queue does not permit
+ * null elements.
+ *
+ *
The {@link #remove()} and {@link #poll()} methods remove and
+ * return the head of the queue.
+ *
+ *
The {@link #element()} and {@link #peek()} methods return, but do
+ * not delete, the head of the queue.
*
*
A priority queue has a capacity. The capacity is the
* size of the array used internally to store the elements on the
- * queue. It is always at least as large as the queue size. As
+ * queue.
+ * It is always at least as large as the queue size. As
* elements are added to a priority queue, its capacity grows
* automatically. The details of the growth policy are not specified.
*
- *
Implementation note: this implementation provides O(log(n)) time
- *for the insertion methods (offer, poll,
- *remove() and add) methods; linear time for the
- *remove(Object) and contains(Object) methods; and
- *constant time for the retrieval methods (peek,
- *element, and size).
+ *
The Iterator provided in method {@link #iterator()} is not
+ * guaranteed to traverse the elements of the PriorityQueue in any
+ * particular order. If you need ordered traversal, consider using
+ * Arrays.sort(pq.toArray()).
+ *
+ *
Note that this implementation is not synchronized.
+ * Multiple threads should not access a PriorityQueue
+ * instance concurrently if any of the threads modifies the list
+ * structurally. Instead, use the thread-safe {@link
+ * java.util.concurrent.PriorityBlockingQueue} class.
+ *
+ *
+ *
Implementation note: this implementation provides O(log(n)) time
+ * for the insertion methods (offer, poll,
+ * remove() and add) methods; linear time for the
+ * remove(Object) and contains(Object) methods; and
+ * constant time for the retrieval methods (peek,
+ * element, and size).
*
*
This class is a member of the
*
* Java Collections Framework.
* @since 1.5
+ * @version %I%, %G%
* @author Josh Bloch
*/
public class PriorityQueue extends AbstractQueue
- implements Queue,
- java.io.Serializable {
+ implements Queue, java.io.Serializable {
+
+ private static final long serialVersionUID = -7720805057305804111L;
+
private static final int DEFAULT_INITIAL_CAPACITY = 11;
/**
@@ -48,7 +78,7 @@ public class PriorityQueue extends Ab
*
* queue.length must be >= 2, even if size == 0.
*/
- private transient E[] queue;
+ private transient Object[] queue;
/**
* The number of elements in the priority queue.
@@ -59,7 +89,7 @@ public class PriorityQueue extends Ab
* The comparator, or null if priority queue uses elements'
* natural ordering.
*/
- private final Comparator comparator;
+ private final Comparator comparator;
/**
* The number of times this priority queue has been
@@ -68,143 +98,286 @@ public class PriorityQueue extends Ab
private transient int modCount = 0;
/**
- * Create a new priority queue with the default initial capacity
+ * Creates a PriorityQueue with the default initial capacity
* (11) that orders its elements according to their natural
- * ordering (using Comparable.)
+ * ordering (using Comparable).
*/
public PriorityQueue() {
- this(DEFAULT_INITIAL_CAPACITY);
+ this(DEFAULT_INITIAL_CAPACITY, null);
}
/**
- * Create a new priority queue with the specified initial capacity
+ * Creates a PriorityQueue with the specified initial capacity
* that orders its elements according to their natural ordering
- * (using Comparable.)
+ * (using Comparable).
*
* @param initialCapacity the initial capacity for this priority queue.
+ * @throws IllegalArgumentException if initialCapacity is less
+ * than 1
*/
public PriorityQueue(int initialCapacity) {
this(initialCapacity, null);
}
/**
- * Create a new priority queue with the specified initial capacity (11)
+ * Creates a PriorityQueue with the specified initial capacity
* that orders its elements according to the specified comparator.
*
* @param initialCapacity the initial capacity for this priority queue.
* @param comparator the comparator used to order this priority queue.
+ * If null then the order depends on the elements' natural
+ * ordering.
+ * @throws IllegalArgumentException if initialCapacity is less
+ * than 1
*/
- public PriorityQueue(int initialCapacity, Comparator comparator) {
+ public PriorityQueue(int initialCapacity,
+ Comparator comparator) {
if (initialCapacity < 1)
- initialCapacity = 1;
- queue = new E[initialCapacity + 1];
+ throw new IllegalArgumentException();
+ this.queue = new Object[initialCapacity + 1];
this.comparator = comparator;
}
/**
- * Create a new priority queue containing the elements in the specified
- * collection. The priority queue has an initial capacity of 110% of the
- * size of the specified collection. If the specified collection
- * implements the {@link Sorted} interface, the priority queue will be
- * sorted according to the same comparator, or according to its elements'
- * natural order if the collection is sorted according to its elements'
- * natural order. If the specified collection does not implement
- * Sorted, the priority queue is ordered according to
- * its elements' natural order.
- *
- * @param initialElements the collection whose elements are to be placed
- * into this priority queue.
- * @throws ClassCastException if elements of the specified collection
- * cannot be compared to one another according to the priority
- * queue's ordering.
- * @throws NullPointerException if the specified collection or an
- * element of the specified collection is null.
+ * Common code to initialize underlying queue array across
+ * constructors below.
*/
- public PriorityQueue(Collection initialElements) {
- int sz = initialElements.size();
+ private void initializeArray(Collection c) {
+ int sz = c.size();
int initialCapacity = (int)Math.min((sz * 110L) / 100,
Integer.MAX_VALUE - 1);
if (initialCapacity < 1)
initialCapacity = 1;
- queue = new E[initialCapacity + 1];
+ this.queue = new Object[initialCapacity + 1];
+ }
+
+ /**
+ * Initially fill elements of the queue array under the
+ * knowledge that it is sorted or is another PQ, in which
+ * case we can just place the elements in the order presented.
+ */
+ private void fillFromSorted(Collection c) {
+ for (Iterator i = c.iterator(); i.hasNext(); )
+ queue[++size] = i.next();
+ }
+
+ /**
+ * Initially fill elements of the queue array that is not to our knowledge
+ * sorted, so we must rearrange the elements to guarantee the heap
+ * invariant.
+ */
+ private void fillFromUnsorted(Collection c) {
+ for (Iterator i = c.iterator(); i.hasNext(); )
+ queue[++size] = i.next();
+ heapify();
+ }
- if (initialElements instanceof Sorted) {
- comparator = ((Sorted)initialElements).comparator();
- for (Iterator i = initialElements.iterator(); i.hasNext(); )
- queue[++size] = i.next();
+ /**
+ * Creates a PriorityQueue containing the elements in the
+ * specified collection. The priority queue has an initial
+ * capacity of 110% of the size of the specified collection or 1
+ * if the collection is empty. If the specified collection is an
+ * instance of a {@link java.util.SortedSet} or is another
+ * PriorityQueue, the priority queue will be sorted
+ * according to the same comparator, or according to its elements'
+ * natural order if the collection is sorted according to its
+ * elements' natural order. Otherwise, the priority queue is
+ * ordered according to its elements' natural order.
+ *
+ * @param c the collection whose elements are to be placed
+ * into this priority queue.
+ * @throws ClassCastException if elements of the specified collection
+ * cannot be compared to one another according to the priority
+ * queue's ordering.
+ * @throws NullPointerException if c or any element within it
+ * is null
+ */
+ public PriorityQueue(Collection c) {
+ initializeArray(c);
+ if (c instanceof SortedSet) {
+ // @fixme double-cast workaround for compiler
+ SortedSet s = (SortedSet) (SortedSet)c;
+ comparator = (Comparator)s.comparator();
+ fillFromSorted(s);
+ } else if (c instanceof PriorityQueue) {
+ PriorityQueue s = (PriorityQueue) c;
+ comparator = (Comparator)s.comparator();
+ fillFromSorted(s);
} else {
comparator = null;
- for (Iterator i = initialElements.iterator(); i.hasNext(); )
- add(i.next());
+ fillFromUnsorted(c);
+ }
+ }
+
+ /**
+ * Creates a PriorityQueue containing the elements in the
+ * specified collection. The priority queue has an initial
+ * capacity of 110% of the size of the specified collection or 1
+ * if the collection is empty. This priority queue will be sorted
+ * according to the same comparator as the given collection, or
+ * according to its elements' natural order if the collection is
+ * sorted according to its elements' natural order.
+ *
+ * @param c the collection whose elements are to be placed
+ * into this priority queue.
+ * @throws ClassCastException if elements of the specified collection
+ * cannot be compared to one another according to the priority
+ * queue's ordering.
+ * @throws NullPointerException if c or any element within it
+ * is null
+ */
+ public PriorityQueue(PriorityQueue c) {
+ initializeArray(c);
+ comparator = (Comparator)c.comparator();
+ fillFromSorted(c);
+ }
+
+ /**
+ * Creates a PriorityQueue containing the elements in the
+ * specified collection. The priority queue has an initial
+ * capacity of 110% of the size of the specified collection or 1
+ * if the collection is empty. This priority queue will be sorted
+ * according to the same comparator as the given collection, or
+ * according to its elements' natural order if the collection is
+ * sorted according to its elements' natural order.
+ *
+ * @param c the collection whose elements are to be placed
+ * into this priority queue.
+ * @throws ClassCastException if elements of the specified collection
+ * cannot be compared to one another according to the priority
+ * queue's ordering.
+ * @throws NullPointerException if c or any element within it
+ * is null
+ */
+ public PriorityQueue(SortedSet c) {
+ initializeArray(c);
+ comparator = (Comparator)c.comparator();
+ fillFromSorted(c);
+ }
+
+ /**
+ * Resize array, if necessary, to be able to hold given index
+ */
+ private void grow(int index) {
+ int newlen = queue.length;
+ if (index < newlen) // don't need to grow
+ return;
+ if (index == Integer.MAX_VALUE)
+ throw new OutOfMemoryError();
+ while (newlen <= index) {
+ if (newlen >= Integer.MAX_VALUE / 2) // avoid overflow
+ newlen = Integer.MAX_VALUE;
+ else
+ newlen <<= 2;
}
+ Object[] newQueue = new Object[newlen];
+ System.arraycopy(queue, 0, newQueue, 0, queue.length);
+ queue = newQueue;
}
+
// Queue Methods
/**
- * Remove and return the minimal element from this priority queue
- * if it contains one or more elements, otherwise return
- * null. The term minimal is defined according to
- * this priority queue's order.
+ * Add the specified element to this priority queue.
*
- * @return the minimal element from this priority queue if it contains
- * one or more elements, otherwise null.
+ * @return true
+ * @throws ClassCastException if the specified element cannot be compared
+ * with elements currently in the priority queue according
+ * to the priority queue's ordering.
+ * @throws NullPointerException if the specified element is null.
*/
+ public boolean offer(E o) {
+ if (o == null)
+ throw new NullPointerException();
+ modCount++;
+ ++size;
+
+ // Grow backing store if necessary
+ if (size >= queue.length)
+ grow(size);
+
+ queue[size] = o;
+ fixUp(size);
+ return true;
+ }
+
public E poll() {
if (size == 0)
return null;
- return remove(1);
+ return remove();
}
+ public E peek() {
+ return (E) queue[1];
+ }
+
+ // Collection Methods - the first two override to update docs
+
/**
- * Return, but do not remove, the minimal element from the
- * priority queue, or return null if the queue is empty.
- * The term minimal is defined according to this priority
- * queue's order. This method returns the same object reference
- * that would be returned by by the poll method. The two
- * methods differ in that this method does not remove the element
- * from the priority queue.
+ * Adds the specified element to this queue.
+ * @return true (as per the general contract of
+ * Collection.add).
*
- * @return the minimal element from this priority queue if it contains
- * one or more elements, otherwise null.
+ * @throws NullPointerException {@inheritDoc}
+ * @throws ClassCastException if the specified element cannot be compared
+ * with elements currently in the priority queue according
+ * to the priority queue's ordering.
*/
- public E peek() {
- return queue[1];
+ public boolean add(E o) {
+ return super.add(o);
+ }
+
+
+ /**
+ * Adds all of the elements in the specified collection to this queue.
+ * The behavior of this operation is undefined if
+ * the specified collection is modified while the operation is in
+ * progress. (This implies that the behavior of this call is undefined if
+ * the specified collection is this queue, and this queue is nonempty.)
+ *
+ * This implementation iterates over the specified collection, and adds
+ * each object returned by the iterator to this collection, in turn.
+ * @throws NullPointerException {@inheritDoc}
+ * @throws ClassCastException if any element cannot be compared
+ * with elements currently in the priority queue according
+ * to the priority queue's ordering.
+ */
+ public boolean addAll(Collection c) {
+ return super.addAll(c);
}
- // Collection Methods
/**
- * Removes a single instance of the specified element from this priority
- * queue, if it is present. Returns true if this collection contained the
- * specified element (or equivalently, if this collection changed as a
+ * Removes a single instance of the specified element from this
+ * queue, if it is present. More formally,
+ * removes an element e such that (o==null ? e==null :
+ * o.equals(e)), if the queue contains one or more such
+ * elements. Returns true if the queue contained the
+ * specified element (or equivalently, if the queue changed as a
* result of the call).
*
- * @param element the element to be removed from this collection,
- * if present.
- * @return true if this collection changed as a result of the
- * call
- * @throws ClassCastException if the specified element cannot be compared
- * with elements currently in the priority queue according
- * to the priority queue's ordering.
- * @throws NullPointerException if the specified element is null.
+ *
This implementation iterates over the queue looking for the
+ * specified element. If it finds the element, it removes the element
+ * from the queue using the iterator's remove method.
+ *
*/
- public boolean remove(Object element) {
- if (element == null)
- throw new NullPointerException();
+ public boolean remove(Object o) {
+ if (o == null)
+ return false;
if (comparator == null) {
for (int i = 1; i <= size; i++) {
- if (((Comparable)queue[i]).compareTo(element) == 0) {
- remove(i);
+ if (((Comparable)queue[i]).compareTo((E)o) == 0) {
+ removeAt(i);
return true;
}
}
} else {
for (int i = 1; i <= size; i++) {
- if (comparator.compare(queue[i], (E) element) == 0) {
- remove(i);
+ if (comparator.compare((E)queue[i], (E)o) == 0) {
+ removeAt(i);
return true;
}
}
@@ -213,18 +386,17 @@ public class PriorityQueue extends Ab
}
/**
- * Returns an iterator over the elements in this priority queue. The
- * elements of the priority queue will be returned by this iterator in the
- * order specified by the queue, which is to say the order they would be
- * returned by repeated calls to poll.
- *
- * @return an Iterator over the elements in this priority queue.
+ * Returns an iterator over the elements in this queue. The iterator
+ * does not return the elements in any particular order.
+ *
+ * @return an iterator over the elements in this queue.
*/
public Iterator iterator() {
return new Itr();
}
private class Itr implements Iterator {
+
/**
* Index (into queue array) of element to be returned by
* subsequent call to next.
@@ -232,9 +404,9 @@ public class PriorityQueue extends Ab
private int cursor = 1;
/**
- * Index of element returned by most recent call to next or
- * previous. Reset to 0 if this element is deleted by a call
- * to remove.
+ * Index of element returned by most recent call to next,
+ * unless that element came from the forgetMeNot list.
+ * Reset to 0 if element is deleted by a call to remove.
*/
private int lastRet = 0;
@@ -245,28 +417,69 @@ public class PriorityQueue extends Ab
*/
private int expectedModCount = modCount;
+ /**
+ * A list of elements that were moved from the unvisited portion of
+ * the heap into the visited portion as a result of "unlucky" element
+ * removals during the iteration. (Unlucky element removals are those
+ * that require a fixup instead of a fixdown.) We must visit all of
+ * the elements in this list to complete the iteration. We do this
+ * after we've completed the "normal" iteration.
+ *
+ * We expect that most iterations, even those involving removals,
+ * will not use need to store elements in this field.
+ */
+ private ArrayList forgetMeNot = null;
+
+ /**
+ * Element returned by the most recent call to next iff that
+ * element was drawn from the forgetMeNot list.
+ */
+ private Object lastRetElt = null;
+
public boolean hasNext() {
- return cursor <= size;
+ return cursor <= size || forgetMeNot != null;
}
public E next() {
checkForComodification();
- if (cursor > size)
+ E result;
+ if (cursor <= size) {
+ result = (E) queue[cursor];
+ lastRet = cursor++;
+ }
+ else if (forgetMeNot == null)
throw new NoSuchElementException();
- E result = queue[cursor];
- lastRet = cursor++;
+ else {
+ int remaining = forgetMeNot.size();
+ result = forgetMeNot.remove(remaining - 1);
+ if (remaining == 1)
+ forgetMeNot = null;
+ lastRet = 0;
+ lastRetElt = result;
+ }
return result;
}
public void remove() {
- if (lastRet == 0)
- throw new IllegalStateException();
checkForComodification();
- PriorityQueue.this.remove(lastRet);
- if (lastRet < cursor)
- cursor--;
- lastRet = 0;
+ if (lastRet != 0) {
+ E moved = PriorityQueue.this.removeAt(lastRet);
+ lastRet = 0;
+ if (moved == null) {
+ cursor--;
+ } else {
+ if (forgetMeNot == null)
+ forgetMeNot = new ArrayList();
+ forgetMeNot.add(moved);
+ }
+ } else if (lastRetElt != null) {
+ PriorityQueue.this.remove(lastRetElt);
+ lastRetElt = null;
+ } else {
+ throw new IllegalStateException();
+ }
+
expectedModCount = modCount;
}
@@ -276,72 +489,69 @@ public class PriorityQueue extends Ab
}
}
- /**
- * Returns the number of elements in this priority queue.
- *
- * @return the number of elements in this priority queue.
- */
public int size() {
return size;
}
/**
- * Add the specified element to this priority queue.
- *
- * @param element the element to add.
- * @return true
- * @throws ClassCastException if the specified element cannot be compared
- * with elements currently in the priority queue according
- * to the priority queue's ordering.
- * @throws NullPointerException if the specified element is null.
+ * Remove all elements from the priority queue.
*/
- public boolean offer(E element) {
- if (element == null)
- throw new NullPointerException();
+ public void clear() {
modCount++;
- // Grow backing store if necessary
- if (++size == queue.length) {
- E[] newQueue = new E[2 * queue.length];
- System.arraycopy(queue, 0, newQueue, 0, size);
- queue = newQueue;
- }
+ // Null out element references to prevent memory leak
+ for (int i=1; i<=size; i++)
+ queue[i] = null;
- queue[size] = element;
- fixUp(size);
- return true;
+ size = 0;
}
/**
- * Remove all elements from the priority queue.
+ * Removes and returns the first element from queue.
*/
- public void clear() {
+ public E remove() {
+ if (size == 0)
+ throw new NoSuchElementException();
modCount++;
- // Null out element references to prevent memory leak
- for (int i=1; i<=size; i++)
- queue[i] = null;
+ E result = (E) queue[1];
+ queue[1] = queue[size];
+ queue[size--] = null; // Drop extra ref to prevent memory leak
+ if (size > 1)
+ fixDown(1);
- size = 0;
+ return result;
}
/**
- * Removes and returns the ith element from queue. Recall
- * that queue is one-based, so 1 <= i <= size.
+ * Removes and returns the ith element from queue. (Recall that queue
+ * is one-based, so 1 <= i <= size.)
*
- * XXX: Could further special-case i==size, but is it worth it?
- * XXX: Could special-case i==0, but is it worth it?
+ * Normally this method leaves the elements at positions from 1 up to i-1,
+ * inclusive, untouched. Under these circumstances, it returns null.
+ * Occasionally, in order to maintain the heap invariant, it must move
+ * the last element of the list to some index in the range [2, i-1],
+ * and move the element previously at position (i/2) to position i.
+ * Under these circumstances, this method returns the element that was
+ * previously at the end of the list and is now at some position between
+ * 2 and i-1 inclusive.
*/
- private E remove(int i) {
- assert i <= size;
+ private E removeAt(int i) {
+ assert i > 0 && i <= size;
modCount++;
- E result = queue[i];
- queue[i] = queue[size];
+ E moved = (E) queue[size];
+ queue[i] = moved;
queue[size--] = null; // Drop extra ref to prevent memory leak
- if (i <= size)
+ if (i <= size) {
fixDown(i);
- return result;
+ if (queue[i] == moved) {
+ fixUp(i);
+ if (queue[i] != moved)
+ return moved;
+ }
+ }
+ return null;
}
/**
@@ -357,17 +567,17 @@ public class PriorityQueue extends Ab
if (comparator == null) {
while (k > 1) {
int j = k >> 1;
- if (((Comparable)queue[j]).compareTo(queue[k]) <= 0)
+ if (((Comparable)queue[j]).compareTo((E)queue[k]) <= 0)
break;
- E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
+ Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
k = j;
}
} else {
while (k > 1) {
- int j = k >> 1;
- if (comparator.compare(queue[j], queue[k]) <= 0)
+ int j = k >>> 1;
+ if (comparator.compare((E)queue[j], (E)queue[k]) <= 0)
break;
- E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
+ Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
k = j;
}
}
@@ -385,34 +595,47 @@ public class PriorityQueue extends Ab
private void fixDown(int k) {
int j;
if (comparator == null) {
- while ((j = k << 1) <= size) {
- if (j 0)
+ while ((j = k << 1) <= size && (j > 0)) {
+ if (j)queue[j]).compareTo((E)queue[j+1]) > 0)
j++; // j indexes smallest kid
- if (((Comparable)queue[k]).compareTo(queue[j]) <= 0)
+
+ if (((Comparable)queue[k]).compareTo((E)queue[j]) <= 0)
break;
- E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
+ Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
k = j;
}
} else {
- while ((j = k << 1) <= size) {
- if (j < size && comparator.compare(queue[j], queue[j+1]) > 0)
+ while ((j = k << 1) <= size && (j > 0)) {
+ if (j 0)
j++; // j indexes smallest kid
- if (comparator.compare(queue[k], queue[j]) <= 0)
+ if (comparator.compare((E)queue[k], (E)queue[j]) <= 0)
break;
- E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
+ Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp;
k = j;
}
}
}
/**
- * Returns the comparator associated with this priority queue, or
- * null if it uses its elements' natural ordering.
+ * Establishes the heap invariant (described above) in the entire tree,
+ * assuming nothing about the order of the elements prior to the call.
+ */
+ private void heapify() {
+ for (int i = size/2; i >= 1; i--)
+ fixDown(i);
+ }
+
+ /**
+ * Returns the comparator used to order this collection, or null
+ * if this collection is sorted according to its elements natural ordering
+ * (using Comparable).
*
- * @return the comparator associated with this priority queue, or
- * null if it uses its elements' natural ordering.
+ * @return the comparator used to order this collection, or null
+ * if this collection is sorted according to its elements natural ordering.
*/
- public Comparator comparator() {
+ public Comparator comparator() {
return comparator;
}
@@ -425,7 +648,7 @@ public class PriorityQueue extends Ab
* Object) in the proper order.
* @param s the stream
*/
- private synchronized void writeObject(java.io.ObjectOutputStream s)
+ private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException{
// Write out element count, and any hidden stuff
s.defaultWriteObject();
@@ -443,18 +666,18 @@ public class PriorityQueue extends Ab
* deserialize it).
* @param s the stream
*/
- private synchronized void readObject(java.io.ObjectInputStream s)
+ private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
// Read in size, and any hidden stuff
s.defaultReadObject();
// Read in array length and allocate array
int arrayLength = s.readInt();
- queue = new E[arrayLength];
+ queue = new Object[arrayLength];
// Read in all elements in the proper order.
for (int i=0; i