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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.6 by brian, Mon Jun 23 02:26:15 2003 UTC vs.
Revision 1.25 by tim, Wed Aug 6 18:42:49 2003 UTC

#	Line 1 | Line 1
1		package java.util;
2
3		/**
4	<	* An unbounded priority queue based on a priority heap.  This queue orders
4	>	* An unbounded priority {@linkplain Queue queue} based on a priority heap.
5	>	* This queue orders
6		* elements according to an order specified at construction time, which is
7	<	* specified in the same manner as {@link TreeSet} and {@link TreeMap}: elements are ordered
7	>	* specified in the same manner as {@link java.util.TreeSet} and
8	>	* {@link java.util.TreeMap}: elements are ordered
9		* either according to their <i>natural order</i> (see {@link Comparable}), or
10	<	* according to a {@link Comparator}, depending on which constructor is used.
11	<	* The {@link #peek}, {@link #poll}, and {@link #remove} methods return the
12	<	* minimal element with respect to the specified ordering.  If multiple
13	<	* elements are tied for least value, no guarantees are made as to
14	<	* which of these elements is returned.
10	>	* according to a {@link java.util.Comparator}, depending on which
11	>	* constructor is used.
12	>	* <p>The <em>head</em> of this queue is the <em>least</em> element with
13	>	* respect to the specified ordering.
14	>	* If multiple elements are tied for least value, the
15	>	* head is one of those elements. A priority queue does not permit
16	>	* <tt>null</tt> elements.
17		*
18	<	* <p>A priority queue has a <i>capacity</i>.  The capacity is the size of
19	<	* the array used internally to store the elements on the queue.  It is always at least
16	<	* as large as the queue size.  As elements are added to a priority queue,
17	<	* its capacity grows automatically.  The details of the growth policy are not
18	<	* specified.
18	>	* <p>The {@link #remove()} and {@link #poll()} methods remove and
19	>	* return the head of the queue.
20		*
21	<	*<p>Implementation note: this implementation provides O(log(n)) time for
22	<	* the insertion methods (<tt>offer</tt>, <tt>poll</tt>, <tt>remove()</tt> and <tt>add</tt>)
23	<	* methods; linear time for the <tt>remove(Object)</tt> and
24	<	* <tt>contains(Object)</tt> methods; and constant time for the retrieval methods (<tt>peek</tt>,
21	>	* <p>The {@link #element()} and {@link #peek()} methods return, but do
22	>	* not delete, the head of the queue.
23	>	*
24	>	* <p>A priority queue has a <i>capacity</i>.  The capacity is the
25	>	* size of the array used internally to store the elements on the
26	>	* queue.
27	>	* It is always at least as large as the queue size.  As
28	>	* elements are added to a priority queue, its capacity grows
29	>	* automatically.  The details of the growth policy are not specified.
30	>	*
31	>	* <p>Implementation note: this implementation provides O(log(n)) time
32	>	* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>,
33	>	* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the
34	>	* <tt>remove(Object)</tt> and <tt>contains(Object)</tt> methods; and
35	>	* constant time for the retrieval methods (<tt>peek</tt>,
36		* <tt>element</tt>, and <tt>size</tt>).
37		*
38		* <p>This class is a member of the
39		* <a href="{@docRoot}/../guide/collections/index.html">
40		* Java Collections Framework</a>.
41	+	* @since 1.5
42	+	* @author Josh Bloch
43		*/
44		public class PriorityQueue<E> extends AbstractQueue<E>
45	<	implements Queue<E>
46	<	{
45	>	implements Queue<E>, java.io.Serializable {
46	>
47		private static final int DEFAULT_INITIAL_CAPACITY = 11;
48
49		/**
#	Line 45 | Line 59 | public class PriorityQueue<E> extends Ab
59		*
60		* queue.length must be >= 2, even if size == 0.
61		*/
62	<	private transient E[] queue;
62	>	private transient Object[] queue;
63
64		/**
65		* The number of elements in the priority queue.
#	Line 56 | Line 70 | public class PriorityQueue<E> extends Ab
70		* The comparator, or null if priority queue uses elements'
71		* natural ordering.
72		*/
73	<	private final Comparator<E> comparator;
73	>	private final Comparator<? super E> comparator;
74
75		/**
76		* The number of times this priority queue has been
#	Line 65 | Line 79 | public class PriorityQueue<E> extends Ab
79		private transient int modCount = 0;
80
81		/**
82	<	* Create a new priority queue with the default initial capacity (11)
83	<	* that orders its elements according to their natural ordering (using <tt>Comparable</tt>.)
82	>	* Creates a <tt>PriorityQueue</tt> with the default initial capacity
83	>	* (11) that orders its elements according to their natural
84	>	* ordering (using <tt>Comparable</tt>).
85		*/
86		public PriorityQueue() {
87	<	this(DEFAULT_INITIAL_CAPACITY);
87	>	this(DEFAULT_INITIAL_CAPACITY, null);
88		}
89
90		/**
91	<	* Create a new priority queue with the specified initial capacity
92	<	* that orders its elements according to their natural ordering (using <tt>Comparable</tt>.)
91	>	* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
92	>	* that orders its elements according to their natural ordering
93	>	* (using <tt>Comparable</tt>).
94		*
95		* @param initialCapacity the initial capacity for this priority queue.
96	+	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
97	+	* than 1
98		*/
99		public PriorityQueue(int initialCapacity) {
100		this(initialCapacity, null);
101		}
102
103		/**
104	<	* Create a new priority queue with the specified initial capacity (11)
104	>	* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
105		* that orders its elements according to the specified comparator.
106		*
107		* @param initialCapacity the initial capacity for this priority queue.
108		* @param comparator the comparator used to order this priority queue.
109	+	* If <tt>null</tt> then the order depends on the elements' natural
110	+	* ordering.
111	+	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
112	+	* than 1
113		*/
114	<	public PriorityQueue(int initialCapacity, Comparator<E> comparator) {
114	>	public PriorityQueue(int initialCapacity,
115	>	Comparator<? super E> comparator) {
116		if (initialCapacity < 1)
117	<	initialCapacity = 1;
118	<	queue = new E[initialCapacity + 1];
117	>	throw new IllegalArgumentException();
118	>	this.queue = new Object[initialCapacity + 1];
119		this.comparator = comparator;
120		}
121
122		/**
123	<	* Create a new priority queue containing the elements in the specified
124	<	* collection.  The priority queue has an initial capacity of 110% of the
102	<	* size of the specified collection. If the specified collection
103	<	* implements the {@link Sorted} interface, the priority queue will be
104	<	* sorted according to the same comparator, or according to its elements'
105	<	* natural order if the collection is sorted according to its elements'
106	<	* natural order.  If the specified collection does not implement
107	<	* <tt>Sorted</tt>, the priority queue is ordered according to
108	<	* its elements' natural order.
109	<	*
110	<	* @param initialElements the collection whose elements are to be placed
111	<	*        into this priority queue.
112	<	* @throws ClassCastException if elements of the specified collection
113	<	*         cannot be compared to one another according to the priority
114	<	*         queue's ordering.
115	<	* @throws NullPointerException if the specified collection or an
116	<	*         element of the specified collection is <tt>null</tt>.
123	>	* Common code to initialize underlying queue array across
124	>	* constructors below.
125		*/
126	<	public PriorityQueue(Collection<E> initialElements) {
127	<	int sz = initialElements.size();
126	>	private void initializeArray(Collection<? extends E> c) {
127	>	int sz = c.size();
128		int initialCapacity = (int)Math.min((sz * 110L) / 100,
129		Integer.MAX_VALUE - 1);
130		if (initialCapacity < 1)
131		initialCapacity = 1;
124	–	queue = new E[initialCapacity + 1];
132
133	<	/* Commented out to compile with generics compiler
133	>	this.queue = new Object[initialCapacity + 1];
134	>	}
135
136	<	if (initialElements instanceof Sorted) {
137	<	comparator = ((Sorted)initialElements).comparator();
138	<	for (Iterator<E> i = initialElements.iterator(); i.hasNext(); )
139	<	queue[++size] = i.next();
140	<	} else {
141	<	*/
142	<	{
136	>	/**
137	>	* Initially fill elements of the queue array under the
138	>	* knowledge that it is sorted or is another PQ, in which
139	>	* case we can just place the elements without fixups.
140	>	*/
141	>	private void fillFromSorted(Collection<? extends E> c) {
142	>	for (Iterator<? extends E> i = c.iterator(); i.hasNext(); )
143	>	queue[++size] = i.next();
144	>	}
145	>
146	>
147	>	/**
148	>	* Initially fill elements of the queue array that is
149	>	* not to our knowledge sorted, so we must add them
150	>	* one by one.
151	>	*/
152	>	private void fillFromUnsorted(Collection<? extends E> c) {
153	>	for (Iterator<? extends E> i = c.iterator(); i.hasNext(); )
154	>	add(i.next());
155	>	}
156	>
157	>	/**
158	>	* Creates a <tt>PriorityQueue</tt> containing the elements in the
159	>	* specified collection.  The priority queue has an initial
160	>	* capacity of 110% of the size of the specified collection or 1
161	>	* if the collection is empty.  If the specified collection is an
162	>	* instance of a {@link java.util.SortedSet} or is another
163	>	* <tt>PriorityQueue</tt>, the priority queue will be sorted
164	>	* according to the same comparator, or according to its elements'
165	>	* natural order if the collection is sorted according to its
166	>	* elements' natural order.  Otherwise, the priority queue is
167	>	* ordered according to its elements' natural order.
168	>	*
169	>	* @param c the collection whose elements are to be placed
170	>	*        into this priority queue.
171	>	* @throws ClassCastException if elements of the specified collection
172	>	*         cannot be compared to one another according to the priority
173	>	*         queue's ordering.
174	>	* @throws NullPointerException if <tt>c</tt> or any element within it
175	>	* is <tt>null</tt>
176	>	*/
177	>	public PriorityQueue(Collection<? extends E> c) {
178	>	initializeArray(c);
179	>	if (c instanceof SortedSet<? extends E>) {
180	>	SortedSet<? extends E> s = (SortedSet<? extends E>) c;
181	>	comparator = (Comparator<? super E>)s.comparator();
182	>	fillFromSorted(s);
183	>	}
184	>	else if (c instanceof PriorityQueue<? extends E>) {
185	>	PriorityQueue<? extends E> s = (PriorityQueue<? extends E>) c;
186	>	comparator = (Comparator<? super E>)s.comparator();
187	>	fillFromSorted(s);
188	>	}
189	>	else {
190		comparator = null;
191	<	for (Iterator<E> i = initialElements.iterator(); i.hasNext(); )
137	<	add(i.next());
191	>	fillFromUnsorted(c);
192		}
193		}
194
195	+	/**
196	+	* Creates a <tt>PriorityQueue</tt> containing the elements in the
197	+	* specified collection.  The priority queue has an initial
198	+	* capacity of 110% of the size of the specified collection or 1
199	+	* if the collection is empty.  This priority queue will be sorted
200	+	* according to the same comparator as the given collection, or
201	+	* according to its elements' natural order if the collection is
202	+	* sorted according to its elements' natural order.
203	+	*
204	+	* @param c the collection whose elements are to be placed
205	+	*        into this priority queue.
206	+	* @throws ClassCastException if elements of the specified collection
207	+	*         cannot be compared to one another according to the priority
208	+	*         queue's ordering.
209	+	* @throws NullPointerException if <tt>c</tt> or any element within it
210	+	* is <tt>null</tt>
211	+	*/
212	+	public PriorityQueue(PriorityQueue<? extends E> c) {
213	+	initializeArray(c);
214	+	comparator = (Comparator<? super E>)c.comparator();
215	+	fillFromSorted(c);
216	+	}
217	+
218	+	/**
219	+	* Creates a <tt>PriorityQueue</tt> containing the elements in the
220	+	* specified collection.  The priority queue has an initial
221	+	* capacity of 110% of the size of the specified collection or 1
222	+	* if the collection is empty.  This priority queue will be sorted
223	+	* according to the same comparator as the given collection, or
224	+	* according to its elements' natural order if the collection is
225	+	* sorted according to its elements' natural order.
226	+	*
227	+	* @param c the collection whose elements are to be placed
228	+	*        into this priority queue.
229	+	* @throws ClassCastException if elements of the specified collection
230	+	*         cannot be compared to one another according to the priority
231	+	*         queue's ordering.
232	+	* @throws NullPointerException if <tt>c</tt> or any element within it
233	+	* is <tt>null</tt>
234	+	*/
235	+	public PriorityQueue(SortedSet<? extends E> c) {
236	+	initializeArray(c);
237	+	comparator = (Comparator<? super E>)c.comparator();
238	+	fillFromSorted(c);
239	+	}
240	+
241	+	/**
242	+	* Resize array, if necessary, to be able to hold given index
243	+	*/
244	+	private void grow(int index) {
245	+	int newlen = queue.length;
246	+	if (index < newlen) // don't need to grow
247	+	return;
248	+	if (index == Integer.MAX_VALUE)
249	+	throw new OutOfMemoryError();
250	+	while (newlen <= index) {
251	+	if (newlen >= Integer.MAX_VALUE / 2)  // avoid overflow
252	+	newlen = Integer.MAX_VALUE;
253	+	else
254	+	newlen <<= 2;
255	+	}
256	+	Object[] newQueue = new Object[newlen];
257	+	System.arraycopy(queue, 0, newQueue, 0, queue.length);
258	+	queue = newQueue;
259	+	}
260	+
261		// Queue Methods
262
263	+
264	+
265		/**
266	<	* Remove and return the minimal element from this priority queue if
145	<	* it contains one or more elements, otherwise return <tt>null</tt>.  The term
146	<	* <i>minimal</i> is defined according to this priority queue's order.
266	>	* Add the specified element to this priority queue.
267		*
268	<	* @return the minimal element from this priority queue if it contains
269	<	*         one or more elements, otherwise <tt>null</tt>.
268	>	* @return <tt>true</tt>
269	>	* @throws ClassCastException if the specified element cannot be compared
270	>	* with elements currently in the priority queue according
271	>	* to the priority queue's ordering.
272	>	* @throws NullPointerException if the specified element is <tt>null</tt>.
273		*/
274	+	public boolean offer(E o) {
275	+	if (o == null)
276	+	throw new NullPointerException();
277	+	modCount++;
278	+	++size;
279	+
280	+	// Grow backing store if necessary
281	+	if (size >= queue.length)
282	+	grow(size);
283	+
284	+	queue[size] = o;
285	+	fixUp(size);
286	+	return true;
287	+	}
288	+
289		public E poll() {
290		if (size == 0)
291		return null;
292	<	return remove(1);
292	>	return (E) remove(1);
293		}
294
295	+	public E peek() {
296	+	return (E) queue[1];
297	+	}
298	+
299	+	// Collection Methods - the first two override to update docs
300	+
301		/**
302	<	* Return, but do not remove, the minimal element from the priority queue,
303	<	* or return <tt>null</tt> if the queue is empty.  The term <i>minimal</i> is
304	<	* defined according to this priority queue's order.  This method returns
161	<	* the same object reference that would be returned by by the
162	<	* <tt>poll</tt> method.  The two methods differ in that this method
163	<	* does not remove the element from the priority queue.
302	>	* Adds the specified element to this queue.
303	>	* @return <tt>true</tt> (as per the general contract of
304	>	* <tt>Collection.add</tt>).
305		*
306	<	* @return the minimal element from this priority queue if it contains
307	<	*         one or more elements, otherwise <tt>null</tt>.
306	>	* @throws NullPointerException {@inheritDoc}
307	>	* @throws ClassCastException if the specified element cannot be compared
308	>	* with elements currently in the priority queue according
309	>	* to the priority queue's ordering.
310		*/
311	<	public E peek() {
312	<	return queue[1];
311	>	public boolean add(E o) {
312	>	return super.add(o);
313		}
314
315	<	// Collection Methods
173	<
315	>
316		/**
317	<	* Removes a single instance of the specified element from this priority
318	<	* queue, if it is present.  Returns true if this collection contained the
319	<	* specified element (or equivalently, if this collection changed as a
317	>	* Adds all of the elements in the specified collection to this queue.
318	>	* The behavior of this operation is undefined if
319	>	* the specified collection is modified while the operation is in
320	>	* progress.  (This implies that the behavior of this call is undefined if
321	>	* the specified collection is this queue, and this queue is nonempty.)
322	>	* <p>
323	>	* This implementation iterates over the specified collection, and adds
324	>	* each object returned by the iterator to this collection, in turn.
325	>	* @throws NullPointerException {@inheritDoc}
326	>	* @throws ClassCastException if any element cannot be compared
327	>	* with elements currently in the priority queue according
328	>	* to the priority queue's ordering.
329	>	*/
330	>	public boolean addAll(Collection<? extends E> c) {
331	>	return super.addAll(c);
332	>	}
333	>
334	>
335	>	/**
336	>	* Removes a single instance of the specified element from this
337	>	* queue, if it is present.  More formally,
338	>	* removes an element <tt>e</tt> such that <tt>(o==null ? e==null :
339	>	* o.equals(e))</tt>, if the queue contains one or more such
340	>	* elements.  Returns <tt>true</tt> if the queue contained the
341	>	* specified element (or equivalently, if the queue changed as a
342		* result of the call).
343		*
344	<	* @param element the element to be removed from this collection, if present.
345	<	* @return <tt>true</tt> if this collection changed as a result of the
346	<	*         call
347	<	* @throws ClassCastException if the specified element cannot be compared
184	<	*            with elements currently in the priority queue according
185	<	*            to the priority queue's ordering.
186	<	* @throws NullPointerException if the specified element is null.
344	>	* <p>This implementation iterates over the queue looking for the
345	>	* specified element.  If it finds the element, it removes the element
346	>	* from the queue using the iterator's remove method.<p>
347	>	*
348		*/
349	<	public boolean remove(Object element) {
350	<	if (element == null)
351	<	throw new NullPointerException();
349	>	public boolean remove(Object o) {
350	>	if (o == null)
351	>	return false;
352
353		if (comparator == null) {
354		for (int i = 1; i <= size; i++) {
355	<	if (((Comparable)queue[i]).compareTo(element) == 0) {
355	>	if (((Comparable<E>)queue[i]).compareTo((E)o) == 0) {
356		remove(i);
357		return true;
358		}
359		}
360		} else {
361		for (int i = 1; i <= size; i++) {
362	<	if (comparator.compare(queue[i], (E) element) == 0) {
362	>	if (comparator.compare((E)queue[i], (E)o) == 0) {
363		remove(i);
364		return true;
365		}
#	Line 208 | Line 369 | public class PriorityQueue<E> extends Ab
369		}
370
371		/**
372	<	* Returns an iterator over the elements in this priority queue.  The
373	<	* elements of the priority queue will be returned by this iterator in the
374	<	* order specified by the queue, which is to say the order they would be
375	<	* returned by repeated calls to <tt>poll</tt>.
215	<	*
216	<	* @return an <tt>Iterator</tt> over the elements in this priority queue.
372	>	* Returns an iterator over the elements in this queue. The iterator
373	>	* does not return the elements in any particular order.
374	>	*
375	>	* @return an iterator over the elements in this queue.
376		*/
377		public Iterator<E> iterator() {
378	<	return new Itr();
378	>	return new Itr();
379		}
380
381		private class Itr implements Iterator<E> {
382	<	/**
383	<	* Index (into queue array) of element to be returned by
382	>	/**
383	>	* Index (into queue array) of element to be returned by
384		* subsequent call to next.
385	<	*/
386	<	int cursor = 1;
385	>	*/
386	>	private int cursor = 1;
387	>
388	>	/**
389	>	* Index of element returned by most recent call to next or
390	>	* previous.  Reset to 0 if this element is deleted by a call
391	>	* to remove.
392	>	*/
393	>	private int lastRet = 0;
394	>
395	>	/**
396	>	* The modCount value that the iterator believes that the backing
397	>	* List should have.  If this expectation is violated, the iterator
398	>	* has detected concurrent modification.
399	>	*/
400	>	private int expectedModCount = modCount;
401
402	<	/**
403	<	* Index of element returned by most recent call to next or
404	<	* previous.  Reset to 0 if this element is deleted by a call
232	<	* to remove.
233	<	*/
234	<	int lastRet = 0;
235	<
236	<	/**
237	<	* The modCount value that the iterator believes that the backing
238	<	* List should have.  If this expectation is violated, the iterator
239	<	* has detected concurrent modification.
240	<	*/
241	<	int expectedModCount = modCount;
242	<
243	<	public boolean hasNext() {
244	<	return cursor <= size;
245	<	}
402	>	public boolean hasNext() {
403	>	return cursor <= size;
404	>	}
405
406	<	public E next() {
406	>	public E next() {
407		checkForComodification();
408		if (cursor > size)
409	<	throw new NoSuchElementException();
410	<	E result = queue[cursor];
409	>	throw new NoSuchElementException();
410	>	E result = (E) queue[cursor];
411		lastRet = cursor++;
412		return result;
413	<	}
413	>	}
414
415	<	public void remove() {
416	<	if (lastRet == 0)
417	<	throw new IllegalStateException();
415	>	public void remove() {
416	>	if (lastRet == 0)
417	>	throw new IllegalStateException();
418		checkForComodification();
419
420		PriorityQueue.this.remove(lastRet);
#	Line 263 | Line 422 | public class PriorityQueue<E> extends Ab
422		cursor--;
423		lastRet = 0;
424		expectedModCount = modCount;
425	<	}
425	>	}
426
427	<	final void checkForComodification() {
428	<	if (modCount != expectedModCount)
429	<	throw new ConcurrentModificationException();
430	<	}
427	>	final void checkForComodification() {
428	>	if (modCount != expectedModCount)
429	>	throw new ConcurrentModificationException();
430	>	}
431		}
432
274	–	/**
275	–	* Returns the number of elements in this priority queue.
276	–	*
277	–	* @return the number of elements in this priority queue.
278	–	*/
433		public int size() {
434		return size;
435		}
436
437		/**
284	–	* Add the specified element to this priority queue.
285	–	*
286	–	* @param element the element to add.
287	–	* @return true
288	–	* @throws ClassCastException if the specified element cannot be compared
289	–	*            with elements currently in the priority queue according
290	–	*            to the priority queue's ordering.
291	–	* @throws NullPointerException if the specified element is null.
292	–	*/
293	–	public boolean offer(E element) {
294	–	if (element == null)
295	–	throw new NullPointerException();
296	–	modCount++;
297	–
298	–	// Grow backing store if necessary
299	–	if (++size == queue.length) {
300	–	E[] newQueue = new E[2 * queue.length];
301	–	System.arraycopy(queue, 0, newQueue, 0, size);
302	–	queue = newQueue;
303	–	}
304	–
305	–	queue[size] = element;
306	–	fixUp(size);
307	–	return true;
308	–	}
309	–
310	–	/**
438		* Remove all elements from the priority queue.
439		*/
440		public void clear() {
#	Line 331 | Line 458 | public class PriorityQueue<E> extends Ab
458		assert i <= size;
459		modCount++;
460
461	<	E result = queue[i];
461	>	E result = (E) queue[i];
462		queue[i] = queue[size];
463		queue[size--] = null;  // Drop extra ref to prevent memory leak
464		if (i <= size)
#	Line 352 | Line 479 | public class PriorityQueue<E> extends Ab
479		if (comparator == null) {
480		while (k > 1) {
481		int j = k >> 1;
482	<	if (((Comparable)queue[j]).compareTo(queue[k]) <= 0)
482	>	if (((Comparable<E>)queue[j]).compareTo((E)queue[k]) <= 0)
483		break;
484	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
484	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
485		k = j;
486		}
487		} else {
488		while (k > 1) {
489		int j = k >> 1;
490	<	if (comparator.compare(queue[j], queue[k]) <= 0)
490	>	if (comparator.compare((E)queue[j], (E)queue[k]) <= 0)
491		break;
492	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
492	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
493		k = j;
494		}
495		}
#	Line 381 | Line 508 | public class PriorityQueue<E> extends Ab
508		int j;
509		if (comparator == null) {
510		while ((j = k << 1) <= size) {
511	<	if (j<size && ((Comparable)queue[j]).compareTo(queue[j+1]) > 0)
511	>	if (j<size && ((Comparable<E>)queue[j]).compareTo((E)queue[j+1]) > 0)
512		j++; // j indexes smallest kid
513	<	if (((Comparable)queue[k]).compareTo(queue[j]) <= 0)
513	>	if (((Comparable<E>)queue[k]).compareTo((E)queue[j]) <= 0)
514		break;
515	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
515	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
516		k = j;
517		}
518		} else {
519		while ((j = k << 1) <= size) {
520	<	if (j < size && comparator.compare(queue[j], queue[j+1]) > 0)
520	>	if (j < size && comparator.compare((E)queue[j], (E)queue[j+1]) > 0)
521		j++; // j indexes smallest kid
522	<	if (comparator.compare(queue[k], queue[j]) <= 0)
522	>	if (comparator.compare((E)queue[k], (E)queue[j]) <= 0)
523		break;
524	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
524	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
525		k = j;
526		}
527		}
528		}
529
530	+
531		/**
532	<	* Returns the comparator associated with this priority queue, or
533	<	* <tt>null</tt> if it uses its elements' natural ordering.
532	>	* Returns the comparator used to order this collection, or <tt>null</tt>
533	>	* if this collection is sorted according to its elements natural ordering
534	>	* (using <tt>Comparable</tt>).
535		*
536	<	* @return the comparator associated with this priority queue, or
537	<	*         <tt>null</tt> if it uses its elements' natural ordering.
536	>	* @return the comparator used to order this collection, or <tt>null</tt>
537	>	* if this collection is sorted according to its elements natural ordering.
538		*/
539	<	Comparator comparator() {
539	>	public Comparator<? super E> comparator() {
540		return comparator;
541		}
542
#	Line 418 | Line 547 | public class PriorityQueue<E> extends Ab
547		* @serialData The length of the array backing the instance is
548		* emitted (int), followed by all of its elements (each an
549		* <tt>Object</tt>) in the proper order.
550	+	* @param s the stream
551		*/
552	<	private synchronized void writeObject(java.io.ObjectOutputStream s)
552	>	private void writeObject(java.io.ObjectOutputStream s)
553		throws java.io.IOException{
554	<	// Write out element count, and any hidden stuff
555	<	s.defaultWriteObject();
554	>	// Write out element count, and any hidden stuff
555	>	s.defaultWriteObject();
556
557		// Write out array length
558		s.writeInt(queue.length);
559
560	<	// Write out all elements in the proper order.
561	<	for (int i=0; i<size; i++)
560	>	// Write out all elements in the proper order.
561	>	for (int i=0; i<size; i++)
562		s.writeObject(queue[i]);
563		}
564
565		/**
566		* Reconstitute the <tt>ArrayList</tt> instance from a stream (that is,
567		* deserialize it).
568	+	* @param s the stream
569		*/
570	<	private synchronized void readObject(java.io.ObjectInputStream s)
570	>	private void readObject(java.io.ObjectInputStream s)
571		throws java.io.IOException, ClassNotFoundException {
572	<	// Read in size, and any hidden stuff
573	<	s.defaultReadObject();
572	>	// Read in size, and any hidden stuff
573	>	s.defaultReadObject();
574
575		// Read in array length and allocate array
576		int arrayLength = s.readInt();
577	<	queue = new E[arrayLength];
577	>	queue = new Object[arrayLength];
578
579	<	// Read in all elements in the proper order.
580	<	for (int i=0; i<size; i++)
581	<	queue[i] = (E)s.readObject();
579	>	// Read in all elements in the proper order.
580	>	for (int i=0; i<size; i++)
581	>	queue[i] = s.readObject();
582		}
583
584		}
585	+

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