3 |
|
/** |
4 |
|
* An unbounded priority queue based on a priority heap. This queue orders |
5 |
|
* elements according to an order specified at construction time, which is |
6 |
< |
* specified in the same manner as {@link TreeSet} and {@link TreeMap}: |
7 |
< |
* elements are ordered |
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 <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 |
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 |
|
* |
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. It is always at least as large as the queue size. As |
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 |
|
* |
78 |
|
private transient int modCount = 0; |
79 |
|
|
80 |
|
/** |
81 |
< |
* Create a <tt>PriorityQueue</tt> with the default initial capacity |
81 |
> |
* Creates 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 |
|
*/ |
87 |
|
} |
88 |
|
|
89 |
|
/** |
90 |
< |
* Create a <tt>PriorityQueue</tt> with the specified initial capacity |
90 |
> |
* Creates 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 |
|
* |
98 |
|
} |
99 |
|
|
100 |
|
/** |
101 |
< |
* Create a <tt>PriorityQueue</tt> with the specified initial capacity |
101 |
> |
* Creates 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. |
116 |
|
} |
117 |
|
|
118 |
|
/** |
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; 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 |
127 |
< |
* <tt>Sorted</tt>, the priority queue is ordered according to |
128 |
< |
* its elements' natural order. |
119 |
> |
* Common code to initialize underlying queue array across |
120 |
> |
* constructors below. |
121 |
> |
*/ |
122 |
> |
private void initializeArray(Collection<? extends E> c) { |
123 |
> |
int sz = c.size(); |
124 |
> |
int initialCapacity = (int)Math.min((sz * 110L) / 100, |
125 |
> |
Integer.MAX_VALUE - 1); |
126 |
> |
if (initialCapacity < 1) |
127 |
> |
initialCapacity = 1; |
128 |
> |
|
129 |
> |
this.queue = new Object[initialCapacity + 1]; |
130 |
> |
} |
131 |
> |
|
132 |
> |
/** |
133 |
> |
* Initially fill elements of the queue array under the |
134 |
> |
* knowledge that it is sorted or is another PQ, in which |
135 |
> |
* case we can just place the elements without fixups. |
136 |
> |
*/ |
137 |
> |
private void fillFromSorted(Collection<? extends E> c) { |
138 |
> |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
139 |
> |
queue[++size] = i.next(); |
140 |
> |
} |
141 |
> |
|
142 |
> |
|
143 |
> |
/** |
144 |
> |
* Initially fill elements of the queue array that is |
145 |
> |
* not to our knowledge sorted, so we must add them |
146 |
> |
* one by one. |
147 |
> |
*/ |
148 |
> |
private void fillFromUnsorted(Collection<? extends E> c) { |
149 |
> |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
150 |
> |
add(i.next()); |
151 |
> |
} |
152 |
> |
|
153 |
> |
/** |
154 |
> |
* Creates a <tt>PriorityQueue</tt> containing the elements in the |
155 |
> |
* specified collection. The priority queue has an initial |
156 |
> |
* capacity of 110% of the size of the specified collection or 1 |
157 |
> |
* if the collection is empty. If the specified collection is an |
158 |
> |
* instance of a {@link SortedSet} or is another |
159 |
> |
* <tt>PriorityQueue</tt>, the priority queue will be sorted |
160 |
> |
* according to the same comparator, or according to its elements' |
161 |
> |
* natural order if the collection is sorted according to its |
162 |
> |
* elements' natural order. Otherwise, the priority queue is |
163 |
> |
* ordered according to its elements' natural order. |
164 |
|
* |
165 |
|
* @param c the collection whose elements are to be placed |
166 |
|
* into this priority queue. |
171 |
|
* is <tt>null</tt> |
172 |
|
*/ |
173 |
|
public PriorityQueue(Collection<? extends E> c) { |
174 |
< |
int sz = c.size(); |
175 |
< |
int initialCapacity = (int)Math.min((sz * 110L) / 100, |
176 |
< |
Integer.MAX_VALUE - 1); |
177 |
< |
if (initialCapacity < 1) |
178 |
< |
initialCapacity = 1; |
179 |
< |
|
180 |
< |
this.queue = new Object[initialCapacity + 1]; |
181 |
< |
|
182 |
< |
if (c instanceof Sorted) { |
183 |
< |
// FIXME: this code assumes too much |
184 |
< |
this.comparator = (Comparator<? super E>) ((Sorted)c).comparator(); |
185 |
< |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
148 |
< |
queue[++size] = i.next(); |
149 |
< |
} else { |
174 |
> |
initializeArray(c); |
175 |
> |
if (c instanceof SortedSet<? extends E>) { |
176 |
> |
SortedSet<? extends E> s = (SortedSet<? extends E>) c; |
177 |
> |
comparator = (Comparator<? super E>)s.comparator(); |
178 |
> |
fillFromSorted(s); |
179 |
> |
} |
180 |
> |
else if (c instanceof PriorityQueue<? extends E>) { |
181 |
> |
PriorityQueue<? extends E> s = (PriorityQueue<? extends E>) c; |
182 |
> |
comparator = (Comparator<? super E>)s.comparator(); |
183 |
> |
fillFromSorted(s); |
184 |
> |
} |
185 |
> |
else { |
186 |
|
comparator = null; |
187 |
< |
for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
152 |
< |
add(i.next()); |
187 |
> |
fillFromUnsorted(c); |
188 |
|
} |
189 |
|
} |
190 |
|
|
191 |
+ |
/** |
192 |
+ |
* Creates a <tt>PriorityQueue</tt> containing the elements in the |
193 |
+ |
* specified collection. The priority queue has an initial |
194 |
+ |
* capacity of 110% of the size of the specified collection or 1 |
195 |
+ |
* if the collection is empty. This priority queue will be sorted |
196 |
+ |
* according to the same comparator as the given collection, or |
197 |
+ |
* according to its elements' natural order if the collection is |
198 |
+ |
* sorted according to its elements' natural order. |
199 |
+ |
* |
200 |
+ |
* @param c the collection whose elements are to be placed |
201 |
+ |
* into this priority queue. |
202 |
+ |
* @throws ClassCastException if elements of the specified collection |
203 |
+ |
* cannot be compared to one another according to the priority |
204 |
+ |
* queue's ordering. |
205 |
+ |
* @throws NullPointerException if <tt>c</tt> or any element within it |
206 |
+ |
* is <tt>null</tt> |
207 |
+ |
*/ |
208 |
+ |
public PriorityQueue(PriorityQueue<? extends E> c) { |
209 |
+ |
initializeArray(c); |
210 |
+ |
comparator = (Comparator<? super E>)c.comparator(); |
211 |
+ |
fillFromSorted(c); |
212 |
+ |
} |
213 |
+ |
|
214 |
+ |
/** |
215 |
+ |
* Creates a <tt>PriorityQueue</tt> containing the elements in the |
216 |
+ |
* specified collection. The priority queue has an initial |
217 |
+ |
* capacity of 110% of the size of the specified collection or 1 |
218 |
+ |
* if the collection is empty. This priority queue will be sorted |
219 |
+ |
* according to the same comparator as the given collection, or |
220 |
+ |
* according to its elements' natural order if the collection is |
221 |
+ |
* sorted according to its elements' natural order. |
222 |
+ |
* |
223 |
+ |
* @param c the collection whose elements are to be placed |
224 |
+ |
* into this priority queue. |
225 |
+ |
* @throws ClassCastException if elements of the specified collection |
226 |
+ |
* cannot be compared to one another according to the priority |
227 |
+ |
* queue's ordering. |
228 |
+ |
* @throws NullPointerException if <tt>c</tt> or any element within it |
229 |
+ |
* is <tt>null</tt> |
230 |
+ |
*/ |
231 |
+ |
public PriorityQueue(SortedSet<? extends E> c) { |
232 |
+ |
initializeArray(c); |
233 |
+ |
comparator = (Comparator<? super E>)c.comparator(); |
234 |
+ |
fillFromSorted(c); |
235 |
+ |
} |
236 |
+ |
|
237 |
+ |
/** |
238 |
+ |
* Resize array, if necessary, to be able to hold given index |
239 |
+ |
*/ |
240 |
+ |
private void grow(int index) { |
241 |
+ |
int newlen = queue.length; |
242 |
+ |
if (index < newlen) // don't need to grow |
243 |
+ |
return; |
244 |
+ |
if (index == Integer.MAX_VALUE) |
245 |
+ |
throw new OutOfMemoryError(); |
246 |
+ |
while (newlen <= index) { |
247 |
+ |
if (newlen >= Integer.MAX_VALUE / 2) // avoid overflow |
248 |
+ |
newlen = Integer.MAX_VALUE; |
249 |
+ |
else |
250 |
+ |
newlen <<= 2; |
251 |
+ |
} |
252 |
+ |
Object[] newQueue = new Object[newlen]; |
253 |
+ |
System.arraycopy(queue, 0, newQueue, 0, queue.length); |
254 |
+ |
queue = newQueue; |
255 |
+ |
} |
256 |
+ |
|
257 |
|
// Queue Methods |
258 |
|
|
259 |
|
/** |
260 |
|
* Add the specified element to this priority queue. |
261 |
|
* |
161 |
– |
* @param element the element to add. |
262 |
|
* @return <tt>true</tt> |
263 |
|
* @throws ClassCastException if the specified element cannot be compared |
264 |
|
* with elements currently in the priority queue according |
265 |
|
* to the priority queue's ordering. |
266 |
< |
* @throws NullPointerException if the specified element is null. |
266 |
> |
* @throws NullPointerException if the specified element is <tt>null</tt>. |
267 |
|
*/ |
268 |
< |
public boolean offer(E element) { |
269 |
< |
if (element == null) |
268 |
> |
public boolean offer(E o) { |
269 |
> |
if (o == null) |
270 |
|
throw new NullPointerException(); |
271 |
|
modCount++; |
272 |
|
++size; |
273 |
|
|
274 |
|
// Grow backing store if necessary |
275 |
< |
while (size >= queue.length) { |
276 |
< |
Object[] newQueue = new Object[2 * queue.length]; |
177 |
< |
System.arraycopy(queue, 0, newQueue, 0, queue.length); |
178 |
< |
queue = newQueue; |
179 |
< |
} |
275 |
> |
if (size >= queue.length) |
276 |
> |
grow(size); |
277 |
|
|
278 |
< |
queue[size] = element; |
278 |
> |
queue[size] = o; |
279 |
|
fixUp(size); |
280 |
|
return true; |
281 |
|
} |
300 |
|
* with elements currently in the priority queue according |
301 |
|
* to the priority queue's ordering. |
302 |
|
*/ |
303 |
< |
public boolean add(E element) { |
304 |
< |
return super.add(element); |
303 |
> |
public boolean add(E o) { |
304 |
> |
return super.add(o); |
305 |
|
} |
306 |
|
|
307 |
|
/** |
211 |
– |
* @throws NullPointerException if any element is <tt>null</tt>. |
308 |
|
* @throws ClassCastException if any element cannot be compared |
309 |
|
* with elements currently in the priority queue according |
310 |
|
* 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> |
313 |
|
*/ |
314 |
|
public boolean addAll(Collection<? extends E> c) { |
315 |
|
return super.addAll(c); |
508 |
|
* <tt>Object</tt>) in the proper order. |
509 |
|
* @param s the stream |
510 |
|
*/ |
511 |
< |
private synchronized void writeObject(java.io.ObjectOutputStream s) |
511 |
> |
private void writeObject(java.io.ObjectOutputStream s) |
512 |
|
throws java.io.IOException{ |
513 |
|
// Write out element count, and any hidden stuff |
514 |
|
s.defaultWriteObject(); |
526 |
|
* deserialize it). |
527 |
|
* @param s the stream |
528 |
|
*/ |
529 |
< |
private synchronized void readObject(java.io.ObjectInputStream s) |
529 |
> |
private void readObject(java.io.ObjectInputStream s) |
530 |
|
throws java.io.IOException, ClassNotFoundException { |
531 |
|
// Read in size, and any hidden stuff |
532 |
|
s.defaultReadObject(); |