3 |
|
/** |
4 |
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* An unbounded priority queue based on a priority heap. This queue orders |
5 |
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* elements according to an order specified at construction time, which is |
6 |
< |
* specified in the same manner as {@link TreeSet} and {@link TreeMap}: |
6 |
> |
* specified in the same manner as {@link TreeSet} and {@link TreeMap}: |
7 |
|
* elements are ordered |
8 |
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* either according to their <i>natural order</i> (see {@link Comparable}), or |
9 |
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* according to a {@link Comparator}, depending on which constructor is used. |
10 |
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* The <em>head</em> of this queue is the least element with respect to the |
11 |
< |
* specified ordering. If multiple elements are tied for least value, the |
12 |
< |
* head is one of those elements. A priority queue does not permit |
11 |
> |
* specified ordering. If multiple elements are tied for least value, the |
12 |
> |
* head is one of those elements. A priority queue does not permit |
13 |
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* <tt>null</tt> elements. |
14 |
< |
* |
14 |
> |
* |
15 |
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* <p>The {@link #remove()} and {@link #poll()} methods remove and |
16 |
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* return the head of the queue. |
17 |
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* |
55 |
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* |
56 |
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* queue.length must be >= 2, even if size == 0. |
57 |
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*/ |
58 |
< |
private transient E[] queue; |
58 |
> |
private transient Object[] queue; |
59 |
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|
60 |
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/** |
61 |
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* The number of elements in the priority queue. |
66 |
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* The comparator, or null if priority queue uses elements' |
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* natural ordering. |
68 |
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*/ |
69 |
< |
private final Comparator<E> comparator; |
69 |
> |
private final Comparator<? super E> comparator; |
70 |
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|
71 |
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/** |
72 |
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* The number of times this priority queue has been |
102 |
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* @param comparator the comparator used to order this priority queue. |
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* If <tt>null</tt> then the order depends on the elements' natural |
104 |
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* ordering. |
105 |
+ |
* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less |
106 |
+ |
* than 1 |
107 |
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*/ |
108 |
< |
public PriorityQueue(int initialCapacity, Comparator<E> comparator) { |
108 |
> |
public PriorityQueue(int initialCapacity, Comparator<? super E> comparator) { |
109 |
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if (initialCapacity < 1) |
110 |
< |
initialCapacity = 1; |
111 |
< |
queue = (E[]) new Object[initialCapacity + 1]; |
110 |
> |
throw new IllegalArgumentException(); |
111 |
> |
this.queue = new Object[initialCapacity + 1]; |
112 |
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this.comparator = comparator; |
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} |
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|
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/** |
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* Create a <tt>PriorityQueue</tt> containing the elements in the specified |
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* collection. The priority queue has an initial capacity of 110% of the |
118 |
< |
* size of the specified collection. If the specified collection |
118 |
> |
* size of the specified collection; or 1 if the collection is empty. |
119 |
> |
* If the specified collection |
120 |
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* implements the {@link Sorted} interface, the priority queue will be |
121 |
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* sorted according to the same comparator, or according to its elements' |
122 |
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* natural order if the collection is sorted according to its elements' |
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* <tt>Sorted</tt>, the priority queue is ordered according to |
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* its elements' natural order. |
126 |
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* |
127 |
< |
* @param initialElements the collection whose elements are to be placed |
127 |
> |
* @param c the collection whose elements are to be placed |
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* into this priority queue. |
129 |
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* @throws ClassCastException if elements of the specified collection |
130 |
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* cannot be compared to one another according to the priority |
131 |
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* queue's ordering. |
132 |
< |
* @throws NullPointerException if the specified collection or an |
133 |
< |
* element of the specified collection is <tt>null</tt>. |
132 |
> |
* @throws NullPointerException if <tt>c</tt> or any element within it |
133 |
> |
* is <tt>null</tt> |
134 |
|
*/ |
135 |
< |
public PriorityQueue(Collection<E> initialElements) { |
136 |
< |
int sz = initialElements.size(); |
135 |
> |
public PriorityQueue(Collection<? extends E> c) { |
136 |
> |
int sz = c.size(); |
137 |
|
int initialCapacity = (int)Math.min((sz * 110L) / 100, |
138 |
|
Integer.MAX_VALUE - 1); |
139 |
|
if (initialCapacity < 1) |
140 |
|
initialCapacity = 1; |
138 |
– |
queue = (E[]) new Object[initialCapacity + 1]; |
141 |
|
|
142 |
< |
if (initialElements instanceof Sorted) { |
143 |
< |
comparator = ((Sorted)initialElements).comparator(); |
144 |
< |
for (Iterator<E> i = initialElements.iterator(); i.hasNext(); ) |
142 |
> |
this.queue = new Object[initialCapacity + 1]; |
143 |
> |
|
144 |
> |
if (c instanceof Sorted) { |
145 |
> |
// FIXME: this code assumes too much |
146 |
> |
this.comparator = (Comparator<? super E>) ((Sorted)c).comparator(); |
147 |
> |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
148 |
|
queue[++size] = i.next(); |
149 |
|
} else { |
150 |
|
comparator = null; |
151 |
< |
for (Iterator<E> i = initialElements.iterator(); i.hasNext(); ) |
151 |
> |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
152 |
|
add(i.next()); |
153 |
|
} |
154 |
|
} |
173 |
|
|
174 |
|
// Grow backing store if necessary |
175 |
|
while (size >= queue.length) { |
176 |
< |
E[] newQueue = (E[]) new Object[2 * queue.length]; |
176 |
> |
Object[] newQueue = new Object[2 * queue.length]; |
177 |
|
System.arraycopy(queue, 0, newQueue, 0, queue.length); |
178 |
|
queue = newQueue; |
179 |
|
} |
186 |
|
public E poll() { |
187 |
|
if (size == 0) |
188 |
|
return null; |
189 |
< |
return remove(1); |
189 |
> |
return (E) remove(1); |
190 |
|
} |
191 |
|
|
192 |
|
public E peek() { |
193 |
< |
return queue[1]; |
193 |
> |
return (E) queue[1]; |
194 |
|
} |
195 |
|
|
196 |
|
// Collection Methods |
199 |
|
|
200 |
|
/** |
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. |
205 |
|
*/ |
206 |
|
public boolean add(E element) { |
207 |
|
return super.add(element); |
208 |
|
} |
209 |
|
|
202 |
– |
// /** |
203 |
– |
// * @throws NullPointerException if any element is <tt>null</tt>. |
204 |
– |
// */ |
205 |
– |
// public boolean addAll(Collection c) { |
206 |
– |
// return super.addAll(c); |
207 |
– |
// } |
208 |
– |
|
210 |
|
/** |
211 |
< |
* @throws NullPointerException if the specified element is <tt>null</tt>. |
211 |
> |
* @throws NullPointerException if any element is <tt>null</tt>. |
212 |
> |
* @throws ClassCastException if any element cannot be compared |
213 |
> |
* with elements currently in the priority queue according |
214 |
> |
* to the priority queue's ordering. |
215 |
|
*/ |
216 |
+ |
public boolean addAll(Collection<? extends E> c) { |
217 |
+ |
return super.addAll(c); |
218 |
+ |
} |
219 |
+ |
|
220 |
|
public boolean remove(Object o) { |
221 |
|
if (o == null) |
222 |
< |
throw new NullPointerException(); |
222 |
> |
return false; |
223 |
|
|
224 |
|
if (comparator == null) { |
225 |
|
for (int i = 1; i <= size; i++) { |
226 |
< |
if (((Comparable)queue[i]).compareTo(o) == 0) { |
226 |
> |
if (((Comparable<E>)queue[i]).compareTo((E)o) == 0) { |
227 |
|
remove(i); |
228 |
|
return true; |
229 |
|
} |
230 |
|
} |
231 |
|
} else { |
232 |
|
for (int i = 1; i <= size; i++) { |
233 |
< |
if (comparator.compare(queue[i], (E)o) == 0) { |
233 |
> |
if (comparator.compare((E)queue[i], (E)o) == 0) { |
234 |
|
remove(i); |
235 |
|
return true; |
236 |
|
} |
239 |
|
return false; |
240 |
|
} |
241 |
|
|
234 |
– |
/** |
235 |
– |
* Returns an iterator over the elements in this priority queue. The |
236 |
– |
* elements of the priority queue will be returned by this iterator in the |
237 |
– |
* order specified by the queue, which is to say the order they would be |
238 |
– |
* returned by repeated calls to <tt>poll</tt>. |
239 |
– |
* |
240 |
– |
* @return an <tt>Iterator</tt> over the elements in this priority queue. |
241 |
– |
*/ |
242 |
|
public Iterator<E> iterator() { |
243 |
|
return new Itr(); |
244 |
|
} |
272 |
|
checkForComodification(); |
273 |
|
if (cursor > size) |
274 |
|
throw new NoSuchElementException(); |
275 |
< |
E result = queue[cursor]; |
275 |
> |
E result = (E) queue[cursor]; |
276 |
|
lastRet = cursor++; |
277 |
|
return result; |
278 |
|
} |
328 |
|
assert i <= size; |
329 |
|
modCount++; |
330 |
|
|
331 |
< |
E result = queue[i]; |
331 |
> |
E result = (E) queue[i]; |
332 |
|
queue[i] = queue[size]; |
333 |
|
queue[size--] = null; // Drop extra ref to prevent memory leak |
334 |
|
if (i <= size) |
349 |
|
if (comparator == null) { |
350 |
|
while (k > 1) { |
351 |
|
int j = k >> 1; |
352 |
< |
if (((Comparable)queue[j]).compareTo(queue[k]) <= 0) |
352 |
> |
if (((Comparable<E>)queue[j]).compareTo((E)queue[k]) <= 0) |
353 |
|
break; |
354 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
354 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
355 |
|
k = j; |
356 |
|
} |
357 |
|
} else { |
358 |
|
while (k > 1) { |
359 |
|
int j = k >> 1; |
360 |
< |
if (comparator.compare(queue[j], queue[k]) <= 0) |
360 |
> |
if (comparator.compare((E)queue[j], (E)queue[k]) <= 0) |
361 |
|
break; |
362 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
362 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
363 |
|
k = j; |
364 |
|
} |
365 |
|
} |
378 |
|
int j; |
379 |
|
if (comparator == null) { |
380 |
|
while ((j = k << 1) <= size) { |
381 |
< |
if (j<size && ((Comparable)queue[j]).compareTo(queue[j+1]) > 0) |
381 |
> |
if (j<size && ((Comparable<E>)queue[j]).compareTo((E)queue[j+1]) > 0) |
382 |
|
j++; // j indexes smallest kid |
383 |
< |
if (((Comparable)queue[k]).compareTo(queue[j]) <= 0) |
383 |
> |
if (((Comparable<E>)queue[k]).compareTo((E)queue[j]) <= 0) |
384 |
|
break; |
385 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
385 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
386 |
|
k = j; |
387 |
|
} |
388 |
|
} else { |
389 |
|
while ((j = k << 1) <= size) { |
390 |
< |
if (j < size && comparator.compare(queue[j], queue[j+1]) > 0) |
390 |
> |
if (j < size && comparator.compare((E)queue[j], (E)queue[j+1]) > 0) |
391 |
|
j++; // j indexes smallest kid |
392 |
< |
if (comparator.compare(queue[k], queue[j]) <= 0) |
392 |
> |
if (comparator.compare((E)queue[k], (E)queue[j]) <= 0) |
393 |
|
break; |
394 |
< |
E tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
394 |
> |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
395 |
|
k = j; |
396 |
|
} |
397 |
|
} |
398 |
|
} |
399 |
|
|
400 |
< |
public Comparator comparator() { |
400 |
> |
public Comparator<? super E> comparator() { |
401 |
|
return comparator; |
402 |
|
} |
403 |
|
|
435 |
|
|
436 |
|
// Read in array length and allocate array |
437 |
|
int arrayLength = s.readInt(); |
438 |
< |
queue = (E[]) new Object[arrayLength]; |
438 |
> |
queue = new Object[arrayLength]; |
439 |
|
|
440 |
|
// Read in all elements in the proper order. |
441 |
|
for (int i=0; i<size; i++) |
442 |
< |
queue[i] = (E)s.readObject(); |
442 |
> |
queue[i] = s.readObject(); |
443 |
|
} |
444 |
|
|
445 |
|
} |