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root/jsr166/jsr166/src/main/java/util/PriorityQueue.java

Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.22 by dl, Tue Aug 5 12:11:08 2003 UTC vs.
Revision 1.29 by dl, Sun Aug 24 23:31:53 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 java.util.TreeSet} and
8		* {@link java.util.TreeMap}: elements are ordered
#	Line 27 | Line 28
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>The Iterator provided in method {@link #iterator()} is <em>not</em>
32	+	* guaranteed to traverse the elements of the PriorityQueue in any
33	+	* particular order. If you need ordered traversal, consider using
34	+	* <tt>Arrays.sort(pq.toArray())</tt>.
35	+	*
36	+	* <p> <strong>Note that this implementation is not synchronized.</strong>
37	+	* Multiple threads should not access a <tt>PriorityQueue</tt>
38	+	* instance concurrently if any of the threads modifies the list
39	+	* structurally. Instead, use the thread-safe {@link
40	+	* java.util.concurrent.BlockingPriorityQueue} class.
41	+	*
42	+	*
43		* <p>Implementation note: this implementation provides O(log(n)) time
44		* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>,
45		* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the
#	Line 80 | Line 93 | public class PriorityQueue<E> extends Ab
93		/**
94		* Creates a <tt>PriorityQueue</tt> with the default initial capacity
95		* (11) that orders its elements according to their natural
96	<	* ordering (using <tt>Comparable</tt>.)
96	>	* ordering (using <tt>Comparable</tt>).
97		*/
98		public PriorityQueue() {
99		this(DEFAULT_INITIAL_CAPACITY, null);
#	Line 89 | Line 102 | public class PriorityQueue<E> extends Ab
102		/**
103		* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
104		* that orders its elements according to their natural ordering
105	<	* (using <tt>Comparable</tt>.)
105	>	* (using <tt>Comparable</tt>).
106		*
107		* @param initialCapacity the initial capacity for this priority queue.
108	+	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
109	+	* than 1
110		*/
111		public PriorityQueue(int initialCapacity) {
112		this(initialCapacity, null);
#	Line 108 | Line 123 | public class PriorityQueue<E> extends Ab
123		* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
124		* than 1
125		*/
126	<	public PriorityQueue(int initialCapacity, Comparator<? super E> comparator) {
126	>	public PriorityQueue(int initialCapacity,
127	>	Comparator<? super E> comparator) {
128		if (initialCapacity < 1)
129		throw new IllegalArgumentException();
130		this.queue = new Object[initialCapacity + 1];
#	Line 155 | Line 171 | public class PriorityQueue<E> extends Ab
171		* specified collection.  The priority queue has an initial
172		* capacity of 110% of the size of the specified collection or 1
173		* if the collection is empty.  If the specified collection is an
174	<	* instance of a {@link SortedSet} or is another
174	>	* instance of a {@link java.util.SortedSet} or is another
175		* <tt>PriorityQueue</tt>, the priority queue will be sorted
176		* according to the same comparator, or according to its elements'
177		* natural order if the collection is sorted according to its
#	Line 172 | Line 188 | public class PriorityQueue<E> extends Ab
188		*/
189		public PriorityQueue(Collection<? extends E> c) {
190		initializeArray(c);
191	<	if (c instanceof SortedSet<? extends E>) {
192	<	SortedSet<? extends E> s = (SortedSet<? extends E>) c;
191	>	if (c instanceof SortedSet) {
192	>	// @fixme double-cast workaround for compiler
193	>	SortedSet<? extends E> s = (SortedSet<? extends E>) (SortedSet)c;
194		comparator = (Comparator<? super E>)s.comparator();
195		fillFromSorted(s);
196	<	}
180	<	else if (c instanceof PriorityQueue<? extends E>) {
196	>	} else if (c instanceof PriorityQueue) {
197		PriorityQueue<? extends E> s = (PriorityQueue<? extends E>) c;
198		comparator = (Comparator<? super E>)s.comparator();
199		fillFromSorted(s);
200	<	}
185	<	else {
200	>	} else {
201		comparator = null;
202		fillFromUnsorted(c);
203		}
#	Line 256 | Line 271 | public class PriorityQueue<E> extends Ab
271
272		// Queue Methods
273
274	+
275	+
276		/**
277		* Add the specified element to this priority queue.
278		*
#	Line 290 | Line 307 | public class PriorityQueue<E> extends Ab
307		return (E) queue[1];
308		}
309
310	<	// Collection Methods
294	<
295	<	// these first two override just to get the throws docs
310	>	// Collection Methods - the first two override to update docs
311
312		/**
313	<	* @throws NullPointerException if the specified element is <tt>null</tt>.
313	>	* Adds the specified element to this queue.
314	>	* @return <tt>true</tt> (as per the general contract of
315	>	* <tt>Collection.add</tt>).
316	>	*
317	>	* @throws NullPointerException {@inheritDoc}
318		* @throws ClassCastException if the specified element cannot be compared
319		* with elements currently in the priority queue according
320		* to the priority queue's ordering.
#	Line 304 | Line 323 | public class PriorityQueue<E> extends Ab
323		return super.add(o);
324		}
325
326	+
327		/**
328	+	* Adds all of the elements in the specified collection to this queue.
329	+	* The behavior of this operation is undefined if
330	+	* the specified collection is modified while the operation is in
331	+	* progress.  (This implies that the behavior of this call is undefined if
332	+	* the specified collection is this queue, and this queue is nonempty.)
333	+	* <p>
334	+	* This implementation iterates over the specified collection, and adds
335	+	* each object returned by the iterator to this collection, in turn.
336	+	* @throws NullPointerException {@inheritDoc}
337		* @throws ClassCastException if any element cannot be compared
338		* with elements currently in the priority queue according
339		* to the priority queue's ordering.
311	–	* @throws NullPointerException if <tt>c</tt> or any element in <tt>c</tt>
312	–	* is <tt>null</tt>
340		*/
341		public boolean addAll(Collection<? extends E> c) {
342		return super.addAll(c);
343		}
344
345	+
346	+	/**
347	+	* Removes a single instance of the specified element from this
348	+	* queue, if it is present.  More formally,
349	+	* removes an element <tt>e</tt> such that <tt>(o==null ? e==null :
350	+	* o.equals(e))</tt>, if the queue contains one or more such
351	+	* elements.  Returns <tt>true</tt> if the queue contained the
352	+	* specified element (or equivalently, if the queue changed as a
353	+	* result of the call).
354	+	*
355	+	* <p>This implementation iterates over the queue looking for the
356	+	* specified element.  If it finds the element, it removes the element
357	+	* from the queue using the iterator's remove method.<p>
358	+	*
359	+	*/
360		public boolean remove(Object o) {
361		if (o == null)
362		return false;
#	Line 337 | Line 379 | public class PriorityQueue<E> extends Ab
379		return false;
380		}
381
382	+	/**
383	+	* Returns an iterator over the elements in this queue. The iterator
384	+	* does not return the elements in any particular order.
385	+	*
386	+	* @return an iterator over the elements in this queue.
387	+	*/
388		public Iterator<E> iterator() {
389		return new Itr();
390		}
#	Line 393 | Line 441 | public class PriorityQueue<E> extends Ab
441		}
442		}
443
396	–	/**
397	–	* Returns the number of elements in this priority queue.
398	–	*
399	–	* @return the number of elements in this priority queue.
400	–	*/
444		public int size() {
445		return size;
446		}
#	Line 495 | Line 538 | public class PriorityQueue<E> extends Ab
538		}
539		}
540
541	+
542	+	/**
543	+	* Returns the comparator used to order this collection, or <tt>null</tt>
544	+	* if this collection is sorted according to its elements natural ordering
545	+	* (using <tt>Comparable</tt>).
546	+	*
547	+	* @return the comparator used to order this collection, or <tt>null</tt>
548	+	* if this collection is sorted according to its elements natural ordering.
549	+	*/
550		public Comparator<? super E> comparator() {
551		return comparator;
552		}

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