2 |
|
|
3 |
|
/** |
4 |
|
* An unbounded priority queue based on a priority heap. This queue orders |
5 |
< |
* elements according to the order specified at creation time. This order is |
6 |
< |
* specified as for {@link TreeSet} and {@link TreeMap}: Elements are ordered |
5 |
> |
* elements according to an order specified at construction time, which is |
6 |
> |
* specified in the same manner as {@link java.util.TreeSet} and |
7 |
> |
* {@link java.util.TreeMap}: elements are ordered |
8 |
|
* either according to their <i>natural order</i> (see {@link Comparable}), or |
9 |
< |
* according to a {@link Comparator}, depending on which constructor is used. |
10 |
< |
* The {@link #peek}, {@link #poll}, and {@link #remove} methods return the |
11 |
< |
* minimal element with respect to the specified ordering. If multiple |
12 |
< |
* these elements are tied for least value, no guarantees are made as to |
13 |
< |
* which of elements is returned. |
9 |
> |
* according to a {@link java.util.Comparator}, depending on which |
10 |
> |
* constructor is used. |
11 |
> |
* <p>The <em>head</em> of this queue is the <em>least</em> element with |
12 |
> |
* respect to the specified ordering. |
13 |
> |
* If multiple elements are tied for least value, the |
14 |
> |
* head is one of those elements. A priority queue does not permit |
15 |
> |
* <tt>null</tt> elements. |
16 |
|
* |
17 |
< |
* <p>Each priority queue has a <i>capacity</i>. The capacity is the size of |
18 |
< |
* the array used 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 list, |
17 |
< |
* its capacity grows automatically. The details of the growth policy are not |
18 |
< |
* specified. |
17 |
> |
* <p>The {@link #remove()} and {@link #poll()} methods remove and |
18 |
> |
* return the head of the queue. |
19 |
|
* |
20 |
< |
*<p>Implementation note: this implementation provides O(log(n)) time for |
21 |
< |
* the <tt>offer</tt>, <tt>poll</tt>, <tt>remove()</tt> and <tt>add</tt> |
22 |
< |
* methods; linear time for the <tt>remove(Object)</tt> and |
23 |
< |
* <tt>contains</tt> methods; and constant time for the <tt>peek</tt>, |
24 |
< |
* <tt>element</tt>, and <tt>size</tt> methods. |
20 |
> |
* <p>The {@link #element()} and {@link #peek()} methods return, but do |
21 |
> |
* not delete, the head of the queue. |
22 |
> |
* |
23 |
> |
* <p>A priority queue has a <i>capacity</i>. The capacity is the |
24 |
> |
* size of the array used internally to store the elements on the |
25 |
> |
* queue. |
26 |
> |
* It is always at least as large as the queue size. As |
27 |
> |
* elements are added to a priority queue, its capacity grows |
28 |
> |
* automatically. The details of the growth policy are not specified. |
29 |
> |
* |
30 |
> |
* <p>Implementation note: this implementation provides O(log(n)) time |
31 |
> |
* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>, |
32 |
> |
* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the |
33 |
> |
* <tt>remove(Object)</tt> and <tt>contains(Object)</tt> methods; and |
34 |
> |
* constant time for the retrieval methods (<tt>peek</tt>, |
35 |
> |
* <tt>element</tt>, and <tt>size</tt>). |
36 |
|
* |
37 |
|
* <p>This class is a member of the |
38 |
|
* <a href="{@docRoot}/../guide/collections/index.html"> |
39 |
|
* Java Collections Framework</a>. |
40 |
+ |
* @since 1.5 |
41 |
+ |
* @author Josh Bloch |
42 |
|
*/ |
43 |
|
public class PriorityQueue<E> extends AbstractQueue<E> |
44 |
< |
implements Queue<E> |
45 |
< |
{ |
44 |
> |
implements Sorted, Queue<E>, java.io.Serializable { |
45 |
> |
|
46 |
|
private static final int DEFAULT_INITIAL_CAPACITY = 11; |
47 |
|
|
48 |
|
/** |
49 |
|
* Priority queue represented as a balanced binary heap: the two children |
50 |
|
* of queue[n] are queue[2*n] and queue[2*n + 1]. The priority queue is |
51 |
|
* ordered by comparator, or by the elements' natural ordering, if |
52 |
< |
* comparator is null: For each node n in the heap, and each descendant |
53 |
< |
* of n, d, n <= d. |
52 |
> |
* comparator is null: For each node n in the heap and each descendant d |
53 |
> |
* of n, n <= d. |
54 |
|
* |
55 |
< |
* The element with the lowest value is in queue[1] (assuming the queue is |
56 |
< |
* nonempty). A one-based array is used in preference to the traditional |
57 |
< |
* zero-based array to simplify parent and child calculations. |
55 |
> |
* The element with the lowest value is in queue[1], assuming the queue is |
56 |
> |
* nonempty. (A one-based array is used in preference to the traditional |
57 |
> |
* zero-based array to simplify parent and child calculations.) |
58 |
|
* |
59 |
|
* queue.length must be >= 2, even if size == 0. |
60 |
|
*/ |
61 |
< |
private transient E[] queue; |
61 |
> |
private transient Object[] queue; |
62 |
|
|
63 |
|
/** |
64 |
|
* The number of elements in the priority queue. |
69 |
|
* The comparator, or null if priority queue uses elements' |
70 |
|
* natural ordering. |
71 |
|
*/ |
72 |
< |
private final Comparator<E> comparator; |
72 |
> |
private final Comparator<? super E> comparator; |
73 |
|
|
74 |
|
/** |
75 |
|
* The number of times this priority queue has been |
78 |
|
private transient int modCount = 0; |
79 |
|
|
80 |
|
/** |
81 |
< |
* Create a new priority queue with the default initial capacity (11) |
82 |
< |
* that orders its elements according to their natural ordering. |
81 |
> |
* Create a <tt>PriorityQueue</tt> with the default initial capacity |
82 |
> |
* (11) that orders its elements according to their natural |
83 |
> |
* ordering (using <tt>Comparable</tt>.) |
84 |
|
*/ |
85 |
|
public PriorityQueue() { |
86 |
< |
this(DEFAULT_INITIAL_CAPACITY); |
86 |
> |
this(DEFAULT_INITIAL_CAPACITY, null); |
87 |
|
} |
88 |
|
|
89 |
|
/** |
90 |
< |
* Create a new priority queue with the specified initial capacity |
91 |
< |
* that orders its elements according to their natural ordering. |
90 |
> |
* Create a <tt>PriorityQueue</tt> with the specified initial capacity |
91 |
> |
* that orders its elements according to their natural ordering |
92 |
> |
* (using <tt>Comparable</tt>.) |
93 |
|
* |
94 |
|
* @param initialCapacity the initial capacity for this priority queue. |
95 |
|
*/ |
98 |
|
} |
99 |
|
|
100 |
|
/** |
101 |
< |
* Create a new priority queue with the specified initial capacity (11) |
101 |
> |
* Create a <tt>PriorityQueue</tt> with the specified initial capacity |
102 |
|
* that orders its elements according to the specified comparator. |
103 |
|
* |
104 |
|
* @param initialCapacity the initial capacity for this priority queue. |
105 |
|
* @param comparator the comparator used to order this priority queue. |
106 |
+ |
* If <tt>null</tt> then the order depends on the elements' natural |
107 |
+ |
* ordering. |
108 |
+ |
* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less |
109 |
+ |
* than 1 |
110 |
|
*/ |
111 |
< |
public PriorityQueue(int initialCapacity, Comparator<E> comparator) { |
111 |
> |
public PriorityQueue(int initialCapacity, Comparator<? super E> comparator) { |
112 |
|
if (initialCapacity < 1) |
113 |
< |
initialCapacity = 1; |
114 |
< |
queue = new E[initialCapacity + 1]; |
113 |
> |
throw new IllegalArgumentException(); |
114 |
> |
this.queue = new Object[initialCapacity + 1]; |
115 |
|
this.comparator = comparator; |
116 |
|
} |
117 |
|
|
118 |
|
/** |
119 |
< |
* Create a new priority queue containing the elements in the specified |
119 |
> |
* Create a <tt>PriorityQueue</tt> containing the elements in the specified |
120 |
|
* collection. The priority queue has an initial capacity of 110% of the |
121 |
< |
* size of the specified collection. If the specified collection |
121 |
> |
* size of the specified collection or 1 if the collection is empty. |
122 |
> |
* If the specified collection |
123 |
|
* implements the {@link Sorted} interface, the priority queue will be |
124 |
|
* sorted according to the same comparator, or according to its elements' |
125 |
|
* natural order if the collection is sorted according to its elements' |
126 |
< |
* natural order. If the specified collection does not implement the |
127 |
< |
* <tt>Sorted</tt> interface, the priority queue is ordered according to |
126 |
> |
* natural order. If the specified collection does not implement |
127 |
> |
* <tt>Sorted</tt>, the priority queue is ordered according to |
128 |
|
* its elements' natural order. |
129 |
|
* |
130 |
< |
* @param initialElements the collection whose elements are to be placed |
130 |
> |
* @param c the collection whose elements are to be placed |
131 |
|
* into this priority queue. |
132 |
|
* @throws ClassCastException if elements of the specified collection |
133 |
|
* cannot be compared to one another according to the priority |
134 |
|
* queue's ordering. |
135 |
< |
* @throws NullPointerException if the specified collection or an |
136 |
< |
* element of the specified collection is <tt>null</tt>. |
135 |
> |
* @throws NullPointerException if <tt>c</tt> or any element within it |
136 |
> |
* is <tt>null</tt> |
137 |
|
*/ |
138 |
< |
public PriorityQueue(Collection<E> initialElements) { |
139 |
< |
int sz = initialElements.size(); |
138 |
> |
public PriorityQueue(Collection<? extends E> c) { |
139 |
> |
int sz = c.size(); |
140 |
|
int initialCapacity = (int)Math.min((sz * 110L) / 100, |
141 |
|
Integer.MAX_VALUE - 1); |
142 |
|
if (initialCapacity < 1) |
143 |
|
initialCapacity = 1; |
124 |
– |
queue = new E[initialCapacity + 1]; |
144 |
|
|
145 |
< |
/* Commented out to compile with generics compiler |
145 |
> |
this.queue = new Object[initialCapacity + 1]; |
146 |
|
|
147 |
< |
if (initialElements instanceof Sorted) { |
148 |
< |
comparator = ((Sorted)initialElements).comparator(); |
130 |
< |
for (Iterator<E> i = initialElements.iterator(); i.hasNext(); ) |
131 |
< |
queue[++size] = i.next(); |
147 |
> |
if (c instanceof Sorted) { |
148 |
> |
comparator = (Comparator<? super E>)((Sorted)c).comparator(); |
149 |
|
} else { |
133 |
– |
*/ |
134 |
– |
{ |
150 |
|
comparator = null; |
136 |
– |
for (Iterator<E> i = initialElements.iterator(); i.hasNext(); ) |
137 |
– |
add(i.next()); |
151 |
|
} |
152 |
+ |
|
153 |
+ |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
154 |
+ |
add(i.next()); |
155 |
|
} |
156 |
|
|
157 |
|
// Queue Methods |
158 |
|
|
159 |
|
/** |
160 |
< |
* Remove and return the minimal element from this priority queue if |
145 |
< |
* it contains one or more elements, otherwise <tt>null</tt>. The term |
146 |
< |
* <i>minimal</i> is defined according to this priority queue's order. |
160 |
> |
* Add the specified element to this priority queue. |
161 |
|
* |
162 |
< |
* @return the minimal element from this priority queue if it contains |
163 |
< |
* one or more elements, otherwise <tt>null</tt>. |
162 |
> |
* @return <tt>true</tt> |
163 |
> |
* @throws ClassCastException if the specified element cannot be compared |
164 |
> |
* with elements currently in the priority queue according |
165 |
> |
* to the priority queue's ordering. |
166 |
> |
* @throws NullPointerException if the specified element is <tt>null</tt>. |
167 |
|
*/ |
168 |
+ |
public boolean offer(E o) { |
169 |
+ |
if (o == null) |
170 |
+ |
throw new NullPointerException(); |
171 |
+ |
modCount++; |
172 |
+ |
++size; |
173 |
+ |
|
174 |
+ |
// Grow backing store if necessary |
175 |
+ |
while (size >= queue.length) { |
176 |
+ |
Object[] newQueue = new Object[2 * queue.length]; |
177 |
+ |
System.arraycopy(queue, 0, newQueue, 0, queue.length); |
178 |
+ |
queue = newQueue; |
179 |
+ |
} |
180 |
+ |
|
181 |
+ |
queue[size] = o; |
182 |
+ |
fixUp(size); |
183 |
+ |
return true; |
184 |
+ |
} |
185 |
+ |
|
186 |
|
public E poll() { |
187 |
|
if (size == 0) |
188 |
|
return null; |
189 |
< |
return remove(1); |
189 |
> |
return (E) remove(1); |
190 |
|
} |
191 |
|
|
157 |
– |
/** |
158 |
– |
* Return, but do not remove, the minimal element from the priority queue, |
159 |
– |
* or <tt>null</tt> if the queue is empty. The term <i>minimal</i> is |
160 |
– |
* 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. |
164 |
– |
* |
165 |
– |
* @return the minimal element from this priority queue if it contains |
166 |
– |
* one or more elements, otherwise <tt>null</tt>. |
167 |
– |
*/ |
192 |
|
public E peek() { |
193 |
< |
return queue[1]; |
193 |
> |
return (E) queue[1]; |
194 |
|
} |
195 |
|
|
196 |
|
// Collection Methods |
197 |
|
|
198 |
+ |
// these first two override just to get the throws docs |
199 |
+ |
|
200 |
|
/** |
201 |
< |
* Removes a single instance of the specified element from this priority |
176 |
< |
* queue, if it is present. Returns true if this collection contained the |
177 |
< |
* specified element (or equivalently, if this collection changed as a |
178 |
< |
* result of the call). |
179 |
< |
* |
180 |
< |
* @param o element to be removed from this collection, if present. |
181 |
< |
* @return <tt>true</tt> if this collection changed as a result of the |
182 |
< |
* call |
201 |
> |
* @throws NullPointerException if the specified element is <tt>null</tt>. |
202 |
|
* @throws ClassCastException if the specified element cannot be compared |
203 |
< |
* with elements currently in the priority queue according |
204 |
< |
* to the priority queue's ordering. |
186 |
< |
* @throws NullPointerException if the specified element is null. |
203 |
> |
* with elements currently in the priority queue according |
204 |
> |
* to the priority queue's ordering. |
205 |
|
*/ |
206 |
< |
public boolean remove(Object element) { |
207 |
< |
if (element == null) |
208 |
< |
throw new NullPointerException(); |
206 |
> |
public boolean add(E o) { |
207 |
> |
return super.add(o); |
208 |
> |
} |
209 |
> |
|
210 |
> |
/** |
211 |
> |
* @throws ClassCastException if any element cannot be compared |
212 |
> |
* with elements currently in the priority queue according |
213 |
> |
* to the priority queue's ordering. |
214 |
> |
* @throws NullPointerException if <tt>c</tt> or any element in <tt>c</tt> |
215 |
> |
* is <tt>null</tt> |
216 |
> |
*/ |
217 |
> |
public boolean addAll(Collection<? extends E> c) { |
218 |
> |
return super.addAll(c); |
219 |
> |
} |
220 |
> |
|
221 |
> |
public boolean remove(Object o) { |
222 |
> |
if (o == null) |
223 |
> |
return false; |
224 |
|
|
225 |
|
if (comparator == null) { |
226 |
|
for (int i = 1; i <= size; i++) { |
227 |
< |
if (((Comparable)queue[i]).compareTo(element) == 0) { |
227 |
> |
if (((Comparable<E>)queue[i]).compareTo((E)o) == 0) { |
228 |
|
remove(i); |
229 |
|
return true; |
230 |
|
} |
231 |
|
} |
232 |
|
} else { |
233 |
|
for (int i = 1; i <= size; i++) { |
234 |
< |
if (comparator.compare(queue[i], (E) element) == 0) { |
234 |
> |
if (comparator.compare((E)queue[i], (E)o) == 0) { |
235 |
|
remove(i); |
236 |
|
return true; |
237 |
|
} |
240 |
|
return false; |
241 |
|
} |
242 |
|
|
210 |
– |
/** |
211 |
– |
* Returns an iterator over the elements in this priority queue. The |
212 |
– |
* first element returned by this iterator is the same element that |
213 |
– |
* would be returned by a call to <tt>peek</tt>. |
214 |
– |
* |
215 |
– |
* @return an <tt>Iterator</tt> over the elements in this priority queue. |
216 |
– |
*/ |
243 |
|
public Iterator<E> iterator() { |
244 |
< |
return new Itr(); |
244 |
> |
return new Itr(); |
245 |
|
} |
246 |
|
|
247 |
|
private class Itr implements Iterator<E> { |
248 |
< |
/** |
249 |
< |
* Index (into queue array) of element to be returned by |
248 |
> |
/** |
249 |
> |
* Index (into queue array) of element to be returned by |
250 |
|
* subsequent call to next. |
251 |
< |
*/ |
252 |
< |
int cursor = 1; |
251 |
> |
*/ |
252 |
> |
private int cursor = 1; |
253 |
|
|
254 |
< |
/** |
255 |
< |
* Index of element returned by most recent call to next or |
256 |
< |
* previous. Reset to 0 if this element is deleted by a call |
257 |
< |
* to remove. |
258 |
< |
*/ |
259 |
< |
int lastRet = 0; |
260 |
< |
|
261 |
< |
/** |
262 |
< |
* The modCount value that the iterator believes that the backing |
263 |
< |
* List should have. If this expectation is violated, the iterator |
264 |
< |
* has detected concurrent modification. |
265 |
< |
*/ |
266 |
< |
int expectedModCount = modCount; |
267 |
< |
|
268 |
< |
public boolean hasNext() { |
269 |
< |
return cursor <= size; |
270 |
< |
} |
254 |
> |
/** |
255 |
> |
* Index of element returned by most recent call to next or |
256 |
> |
* previous. Reset to 0 if this element is deleted by a call |
257 |
> |
* to remove. |
258 |
> |
*/ |
259 |
> |
private int lastRet = 0; |
260 |
> |
|
261 |
> |
/** |
262 |
> |
* The modCount value that the iterator believes that the backing |
263 |
> |
* List should have. If this expectation is violated, the iterator |
264 |
> |
* has detected concurrent modification. |
265 |
> |
*/ |
266 |
> |
private int expectedModCount = modCount; |
267 |
> |
|
268 |
> |
public boolean hasNext() { |
269 |
> |
return cursor <= size; |
270 |
> |
} |
271 |
|
|
272 |
< |
public E next() { |
272 |
> |
public E next() { |
273 |
|
checkForComodification(); |
274 |
|
if (cursor > size) |
275 |
< |
throw new NoSuchElementException(); |
276 |
< |
E result = queue[cursor]; |
275 |
> |
throw new NoSuchElementException(); |
276 |
> |
E result = (E) queue[cursor]; |
277 |
|
lastRet = cursor++; |
278 |
|
return result; |
279 |
< |
} |
279 |
> |
} |
280 |
|
|
281 |
< |
public void remove() { |
282 |
< |
if (lastRet == 0) |
283 |
< |
throw new IllegalStateException(); |
281 |
> |
public void remove() { |
282 |
> |
if (lastRet == 0) |
283 |
> |
throw new IllegalStateException(); |
284 |
|
checkForComodification(); |
285 |
|
|
286 |
|
PriorityQueue.this.remove(lastRet); |
288 |
|
cursor--; |
289 |
|
lastRet = 0; |
290 |
|
expectedModCount = modCount; |
291 |
< |
} |
291 |
> |
} |
292 |
|
|
293 |
< |
final void checkForComodification() { |
294 |
< |
if (modCount != expectedModCount) |
295 |
< |
throw new ConcurrentModificationException(); |
296 |
< |
} |
293 |
> |
final void checkForComodification() { |
294 |
> |
if (modCount != expectedModCount) |
295 |
> |
throw new ConcurrentModificationException(); |
296 |
> |
} |
297 |
|
} |
298 |
|
|
299 |
|
/** |
300 |
|
* Returns the number of elements in this priority queue. |
301 |
< |
* |
301 |
> |
* |
302 |
|
* @return the number of elements in this priority queue. |
303 |
|
*/ |
304 |
|
public int size() { |
306 |
|
} |
307 |
|
|
308 |
|
/** |
283 |
– |
* Add the specified element to this priority queue. |
284 |
– |
* |
285 |
– |
* @param element the element to add. |
286 |
– |
* @return true |
287 |
– |
* @throws ClassCastException if the specified element cannot be compared |
288 |
– |
* with elements currently in the priority queue according |
289 |
– |
* to the priority queue's ordering. |
290 |
– |
* @throws NullPointerException if the specified element is null. |
291 |
– |
*/ |
292 |
– |
public boolean offer(E element) { |
293 |
– |
if (element == null) |
294 |
– |
throw new NullPointerException(); |
295 |
– |
modCount++; |
296 |
– |
|
297 |
– |
// Grow backing store if necessary |
298 |
– |
if (++size == queue.length) { |
299 |
– |
E[] newQueue = new E[2 * queue.length]; |
300 |
– |
System.arraycopy(queue, 0, newQueue, 0, size); |
301 |
– |
queue = newQueue; |
302 |
– |
} |
303 |
– |
|
304 |
– |
queue[size] = element; |
305 |
– |
fixUp(size); |
306 |
– |
return true; |
307 |
– |
} |
308 |
– |
|
309 |
– |
/** |
309 |
|
* Remove all elements from the priority queue. |
310 |
|
*/ |
311 |
|
public void clear() { |
329 |
|
assert i <= size; |
330 |
|
modCount++; |
331 |
|
|
332 |
< |
E result = queue[i]; |
332 |
> |
E result = (E) queue[i]; |
333 |
|
queue[i] = queue[size]; |
334 |
|
queue[size--] = null; // Drop extra ref to prevent memory leak |
335 |
|
if (i <= size) |
350 |
|
if (comparator == null) { |
351 |
|
while (k > 1) { |
352 |
|
int j = k >> 1; |
353 |
< |
if (((Comparable)queue[j]).compareTo(queue[k]) <= 0) |
353 |
> |
if (((Comparable<E>)queue[j]).compareTo((E)queue[k]) <= 0) |
354 |
|
break; |
355 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
355 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
356 |
|
k = j; |
357 |
|
} |
358 |
|
} else { |
359 |
|
while (k > 1) { |
360 |
|
int j = k >> 1; |
361 |
< |
if (comparator.compare(queue[j], queue[k]) <= 0) |
361 |
> |
if (comparator.compare((E)queue[j], (E)queue[k]) <= 0) |
362 |
|
break; |
363 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
363 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
364 |
|
k = j; |
365 |
|
} |
366 |
|
} |
379 |
|
int j; |
380 |
|
if (comparator == null) { |
381 |
|
while ((j = k << 1) <= size) { |
382 |
< |
if (j<size && ((Comparable)queue[j]).compareTo(queue[j+1]) > 0) |
382 |
> |
if (j<size && ((Comparable<E>)queue[j]).compareTo((E)queue[j+1]) > 0) |
383 |
|
j++; // j indexes smallest kid |
384 |
< |
if (((Comparable)queue[k]).compareTo(queue[j]) <= 0) |
384 |
> |
if (((Comparable<E>)queue[k]).compareTo((E)queue[j]) <= 0) |
385 |
|
break; |
386 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
386 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
387 |
|
k = j; |
388 |
|
} |
389 |
|
} else { |
390 |
|
while ((j = k << 1) <= size) { |
391 |
< |
if (j < size && comparator.compare(queue[j], queue[j+1]) > 0) |
391 |
> |
if (j < size && comparator.compare((E)queue[j], (E)queue[j+1]) > 0) |
392 |
|
j++; // j indexes smallest kid |
393 |
< |
if (comparator.compare(queue[k], queue[j]) <= 0) |
393 |
> |
if (comparator.compare((E)queue[k], (E)queue[j]) <= 0) |
394 |
|
break; |
395 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
395 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
396 |
|
k = j; |
397 |
|
} |
398 |
|
} |
399 |
|
} |
400 |
|
|
401 |
< |
/** |
403 |
< |
* Returns the comparator associated with this priority queue, or |
404 |
< |
* <tt>null</tt> if it uses its elements' natural ordering. |
405 |
< |
* |
406 |
< |
* @return the comparator associated with this priority queue, or |
407 |
< |
* <tt>null</tt> if it uses its elements' natural ordering. |
408 |
< |
*/ |
409 |
< |
Comparator comparator() { |
401 |
> |
public Comparator<? super E> comparator() { |
402 |
|
return comparator; |
403 |
|
} |
404 |
|
|
409 |
|
* @serialData The length of the array backing the instance is |
410 |
|
* emitted (int), followed by all of its elements (each an |
411 |
|
* <tt>Object</tt>) in the proper order. |
412 |
+ |
* @param s the stream |
413 |
|
*/ |
414 |
|
private synchronized void writeObject(java.io.ObjectOutputStream s) |
415 |
|
throws java.io.IOException{ |
416 |
< |
// Write out element count, and any hidden stuff |
417 |
< |
s.defaultWriteObject(); |
416 |
> |
// Write out element count, and any hidden stuff |
417 |
> |
s.defaultWriteObject(); |
418 |
|
|
419 |
|
// Write out array length |
420 |
|
s.writeInt(queue.length); |
421 |
|
|
422 |
< |
// Write out all elements in the proper order. |
423 |
< |
for (int i=0; i<size; i++) |
422 |
> |
// Write out all elements in the proper order. |
423 |
> |
for (int i=0; i<size; i++) |
424 |
|
s.writeObject(queue[i]); |
425 |
|
} |
426 |
|
|
427 |
|
/** |
428 |
|
* Reconstitute the <tt>ArrayList</tt> instance from a stream (that is, |
429 |
|
* deserialize it). |
430 |
+ |
* @param s the stream |
431 |
|
*/ |
432 |
|
private synchronized void readObject(java.io.ObjectInputStream s) |
433 |
|
throws java.io.IOException, ClassNotFoundException { |
434 |
< |
// Read in size, and any hidden stuff |
435 |
< |
s.defaultReadObject(); |
434 |
> |
// Read in size, and any hidden stuff |
435 |
> |
s.defaultReadObject(); |
436 |
|
|
437 |
|
// Read in array length and allocate array |
438 |
|
int arrayLength = s.readInt(); |
439 |
< |
queue = new E[arrayLength]; |
439 |
> |
queue = new Object[arrayLength]; |
440 |
|
|
441 |
< |
// Read in all elements in the proper order. |
442 |
< |
for (int i=0; i<size; i++) |
443 |
< |
queue[i] = (E)s.readObject(); |
441 |
> |
// Read in all elements in the proper order. |
442 |
> |
for (int i=0; i<size; i++) |
443 |
> |
queue[i] = s.readObject(); |
444 |
|
} |
445 |
|
|
446 |
|
} |
447 |
+ |
|