J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 3 | * |
| 4 | * This code is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU General Public License version 2 only, as |
| 6 | * published by the Free Software Foundation. Sun designates this |
| 7 | * particular file as subject to the "Classpath" exception as provided |
| 8 | * by Sun in the LICENSE file that accompanied this code. |
| 9 | * |
| 10 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 13 | * version 2 for more details (a copy is included in the LICENSE file that |
| 14 | * accompanied this code). |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License version |
| 17 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 18 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 19 | * |
| 20 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 21 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 22 | * have any questions. |
| 23 | */ |
| 24 | |
| 25 | /* |
| 26 | * This file is available under and governed by the GNU General Public |
| 27 | * License version 2 only, as published by the Free Software Foundation. |
| 28 | * However, the following notice accompanied the original version of this |
| 29 | * file: |
| 30 | * |
| 31 | * Written by Doug Lea with assistance from members of JCP JSR-166 |
| 32 | * Expert Group and released to the public domain, as explained at |
| 33 | * http://creativecommons.org/licenses/publicdomain |
| 34 | */ |
| 35 | |
| 36 | package java.util.concurrent; |
| 37 | |
| 38 | import java.util.concurrent.locks.*; |
| 39 | import java.util.*; |
| 40 | |
| 41 | /** |
| 42 | * An unbounded {@linkplain BlockingQueue blocking queue} that uses |
| 43 | * the same ordering rules as class {@link PriorityQueue} and supplies |
| 44 | * blocking retrieval operations. While this queue is logically |
| 45 | * unbounded, attempted additions may fail due to resource exhaustion |
| 46 | * (causing <tt>OutOfMemoryError</tt>). This class does not permit |
| 47 | * <tt>null</tt> elements. A priority queue relying on {@linkplain |
| 48 | * Comparable natural ordering} also does not permit insertion of |
| 49 | * non-comparable objects (doing so results in |
| 50 | * <tt>ClassCastException</tt>). |
| 51 | * |
| 52 | * <p>This class and its iterator implement all of the |
| 53 | * <em>optional</em> methods of the {@link Collection} and {@link |
| 54 | * Iterator} interfaces. The Iterator provided in method {@link |
| 55 | * #iterator()} is <em>not</em> guaranteed to traverse the elements of |
| 56 | * the PriorityBlockingQueue in any particular order. If you need |
| 57 | * ordered traversal, consider using |
| 58 | * <tt>Arrays.sort(pq.toArray())</tt>. Also, method <tt>drainTo</tt> |
| 59 | * can be used to <em>remove</em> some or all elements in priority |
| 60 | * order and place them in another collection. |
| 61 | * |
| 62 | * <p>Operations on this class make no guarantees about the ordering |
| 63 | * of elements with equal priority. If you need to enforce an |
| 64 | * ordering, you can define custom classes or comparators that use a |
| 65 | * secondary key to break ties in primary priority values. For |
| 66 | * example, here is a class that applies first-in-first-out |
| 67 | * tie-breaking to comparable elements. To use it, you would insert a |
| 68 | * <tt>new FIFOEntry(anEntry)</tt> instead of a plain entry object. |
| 69 | * |
| 70 | * <pre> |
| 71 | * class FIFOEntry<E extends Comparable<? super E>> |
| 72 | * implements Comparable<FIFOEntry<E>> { |
| 73 | * final static AtomicLong seq = new AtomicLong(); |
| 74 | * final long seqNum; |
| 75 | * final E entry; |
| 76 | * public FIFOEntry(E entry) { |
| 77 | * seqNum = seq.getAndIncrement(); |
| 78 | * this.entry = entry; |
| 79 | * } |
| 80 | * public E getEntry() { return entry; } |
| 81 | * public int compareTo(FIFOEntry<E> other) { |
| 82 | * int res = entry.compareTo(other.entry); |
| 83 | * if (res == 0 && other.entry != this.entry) |
| 84 | * res = (seqNum < other.seqNum ? -1 : 1); |
| 85 | * return res; |
| 86 | * } |
| 87 | * }</pre> |
| 88 | * |
| 89 | * <p>This class is a member of the |
| 90 | * <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
| 91 | * Java Collections Framework</a>. |
| 92 | * |
| 93 | * @since 1.5 |
| 94 | * @author Doug Lea |
| 95 | * @param <E> the type of elements held in this collection |
| 96 | */ |
| 97 | public class PriorityBlockingQueue<E> extends AbstractQueue<E> |
| 98 | implements BlockingQueue<E>, java.io.Serializable { |
| 99 | private static final long serialVersionUID = 5595510919245408276L; |
| 100 | |
| 101 | private final PriorityQueue<E> q; |
| 102 | private final ReentrantLock lock = new ReentrantLock(true); |
| 103 | private final Condition notEmpty = lock.newCondition(); |
| 104 | |
| 105 | /** |
| 106 | * Creates a <tt>PriorityBlockingQueue</tt> with the default |
| 107 | * initial capacity (11) that orders its elements according to |
| 108 | * their {@linkplain Comparable natural ordering}. |
| 109 | */ |
| 110 | public PriorityBlockingQueue() { |
| 111 | q = new PriorityQueue<E>(); |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * Creates a <tt>PriorityBlockingQueue</tt> with the specified |
| 116 | * initial capacity that orders its elements according to their |
| 117 | * {@linkplain Comparable natural ordering}. |
| 118 | * |
| 119 | * @param initialCapacity the initial capacity for this priority queue |
| 120 | * @throws IllegalArgumentException if <tt>initialCapacity</tt> is less |
| 121 | * than 1 |
| 122 | */ |
| 123 | public PriorityBlockingQueue(int initialCapacity) { |
| 124 | q = new PriorityQueue<E>(initialCapacity, null); |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * Creates a <tt>PriorityBlockingQueue</tt> with the specified initial |
| 129 | * capacity that orders its elements according to the specified |
| 130 | * comparator. |
| 131 | * |
| 132 | * @param initialCapacity the initial capacity for this priority queue |
| 133 | * @param comparator the comparator that will be used to order this |
| 134 | * priority queue. If {@code null}, the {@linkplain Comparable |
| 135 | * natural ordering} of the elements will be used. |
| 136 | * @throws IllegalArgumentException if <tt>initialCapacity</tt> is less |
| 137 | * than 1 |
| 138 | */ |
| 139 | public PriorityBlockingQueue(int initialCapacity, |
| 140 | Comparator<? super E> comparator) { |
| 141 | q = new PriorityQueue<E>(initialCapacity, comparator); |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Creates a <tt>PriorityBlockingQueue</tt> containing the elements |
| 146 | * in the specified collection. If the specified collection is a |
| 147 | * {@link SortedSet} or a {@link PriorityQueue}, this |
| 148 | * priority queue will be ordered according to the same ordering. |
| 149 | * Otherwise, this priority queue will be ordered according to the |
| 150 | * {@linkplain Comparable natural ordering} of its elements. |
| 151 | * |
| 152 | * @param c the collection whose elements are to be placed |
| 153 | * into this priority queue |
| 154 | * @throws ClassCastException if elements of the specified collection |
| 155 | * cannot be compared to one another according to the priority |
| 156 | * queue's ordering |
| 157 | * @throws NullPointerException if the specified collection or any |
| 158 | * of its elements are null |
| 159 | */ |
| 160 | public PriorityBlockingQueue(Collection<? extends E> c) { |
| 161 | q = new PriorityQueue<E>(c); |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * Inserts the specified element into this priority queue. |
| 166 | * |
| 167 | * @param e the element to add |
| 168 | * @return <tt>true</tt> (as specified by {@link Collection#add}) |
| 169 | * @throws ClassCastException if the specified element cannot be compared |
| 170 | * with elements currently in the priority queue according to the |
| 171 | * priority queue's ordering |
| 172 | * @throws NullPointerException if the specified element is null |
| 173 | */ |
| 174 | public boolean add(E e) { |
| 175 | return offer(e); |
| 176 | } |
| 177 | |
| 178 | /** |
| 179 | * Inserts the specified element into this priority queue. |
| 180 | * |
| 181 | * @param e the element to add |
| 182 | * @return <tt>true</tt> (as specified by {@link Queue#offer}) |
| 183 | * @throws ClassCastException if the specified element cannot be compared |
| 184 | * with elements currently in the priority queue according to the |
| 185 | * priority queue's ordering |
| 186 | * @throws NullPointerException if the specified element is null |
| 187 | */ |
| 188 | public boolean offer(E e) { |
| 189 | final ReentrantLock lock = this.lock; |
| 190 | lock.lock(); |
| 191 | try { |
| 192 | boolean ok = q.offer(e); |
| 193 | assert ok; |
| 194 | notEmpty.signal(); |
| 195 | return true; |
| 196 | } finally { |
| 197 | lock.unlock(); |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | /** |
| 202 | * Inserts the specified element into this priority queue. As the queue is |
| 203 | * unbounded this method will never block. |
| 204 | * |
| 205 | * @param e the element to add |
| 206 | * @throws ClassCastException if the specified element cannot be compared |
| 207 | * with elements currently in the priority queue according to the |
| 208 | * priority queue's ordering |
| 209 | * @throws NullPointerException if the specified element is null |
| 210 | */ |
| 211 | public void put(E e) { |
| 212 | offer(e); // never need to block |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * Inserts the specified element into this priority queue. As the queue is |
| 217 | * unbounded this method will never block. |
| 218 | * |
| 219 | * @param e the element to add |
| 220 | * @param timeout This parameter is ignored as the method never blocks |
| 221 | * @param unit This parameter is ignored as the method never blocks |
| 222 | * @return <tt>true</tt> |
| 223 | * @throws ClassCastException if the specified element cannot be compared |
| 224 | * with elements currently in the priority queue according to the |
| 225 | * priority queue's ordering |
| 226 | * @throws NullPointerException if the specified element is null |
| 227 | */ |
| 228 | public boolean offer(E e, long timeout, TimeUnit unit) { |
| 229 | return offer(e); // never need to block |
| 230 | } |
| 231 | |
| 232 | public E poll() { |
| 233 | final ReentrantLock lock = this.lock; |
| 234 | lock.lock(); |
| 235 | try { |
| 236 | return q.poll(); |
| 237 | } finally { |
| 238 | lock.unlock(); |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | public E take() throws InterruptedException { |
| 243 | final ReentrantLock lock = this.lock; |
| 244 | lock.lockInterruptibly(); |
| 245 | try { |
| 246 | try { |
| 247 | while (q.size() == 0) |
| 248 | notEmpty.await(); |
| 249 | } catch (InterruptedException ie) { |
| 250 | notEmpty.signal(); // propagate to non-interrupted thread |
| 251 | throw ie; |
| 252 | } |
| 253 | E x = q.poll(); |
| 254 | assert x != null; |
| 255 | return x; |
| 256 | } finally { |
| 257 | lock.unlock(); |
| 258 | } |
| 259 | } |
| 260 | |
| 261 | public E poll(long timeout, TimeUnit unit) throws InterruptedException { |
| 262 | long nanos = unit.toNanos(timeout); |
| 263 | final ReentrantLock lock = this.lock; |
| 264 | lock.lockInterruptibly(); |
| 265 | try { |
| 266 | for (;;) { |
| 267 | E x = q.poll(); |
| 268 | if (x != null) |
| 269 | return x; |
| 270 | if (nanos <= 0) |
| 271 | return null; |
| 272 | try { |
| 273 | nanos = notEmpty.awaitNanos(nanos); |
| 274 | } catch (InterruptedException ie) { |
| 275 | notEmpty.signal(); // propagate to non-interrupted thread |
| 276 | throw ie; |
| 277 | } |
| 278 | } |
| 279 | } finally { |
| 280 | lock.unlock(); |
| 281 | } |
| 282 | } |
| 283 | |
| 284 | public E peek() { |
| 285 | final ReentrantLock lock = this.lock; |
| 286 | lock.lock(); |
| 287 | try { |
| 288 | return q.peek(); |
| 289 | } finally { |
| 290 | lock.unlock(); |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | /** |
| 295 | * Returns the comparator used to order the elements in this queue, |
| 296 | * or <tt>null</tt> if this queue uses the {@linkplain Comparable |
| 297 | * natural ordering} of its elements. |
| 298 | * |
| 299 | * @return the comparator used to order the elements in this queue, |
| 300 | * or <tt>null</tt> if this queue uses the natural |
| 301 | * ordering of its elements |
| 302 | */ |
| 303 | public Comparator<? super E> comparator() { |
| 304 | return q.comparator(); |
| 305 | } |
| 306 | |
| 307 | public int size() { |
| 308 | final ReentrantLock lock = this.lock; |
| 309 | lock.lock(); |
| 310 | try { |
| 311 | return q.size(); |
| 312 | } finally { |
| 313 | lock.unlock(); |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | /** |
| 318 | * Always returns <tt>Integer.MAX_VALUE</tt> because |
| 319 | * a <tt>PriorityBlockingQueue</tt> is not capacity constrained. |
| 320 | * @return <tt>Integer.MAX_VALUE</tt> |
| 321 | */ |
| 322 | public int remainingCapacity() { |
| 323 | return Integer.MAX_VALUE; |
| 324 | } |
| 325 | |
| 326 | /** |
| 327 | * Removes a single instance of the specified element from this queue, |
| 328 | * if it is present. More formally, removes an element {@code e} such |
| 329 | * that {@code o.equals(e)}, if this queue contains one or more such |
| 330 | * elements. Returns {@code true} if and only if this queue contained |
| 331 | * the specified element (or equivalently, if this queue changed as a |
| 332 | * result of the call). |
| 333 | * |
| 334 | * @param o element to be removed from this queue, if present |
| 335 | * @return <tt>true</tt> if this queue changed as a result of the call |
| 336 | */ |
| 337 | public boolean remove(Object o) { |
| 338 | final ReentrantLock lock = this.lock; |
| 339 | lock.lock(); |
| 340 | try { |
| 341 | return q.remove(o); |
| 342 | } finally { |
| 343 | lock.unlock(); |
| 344 | } |
| 345 | } |
| 346 | |
| 347 | /** |
| 348 | * Returns {@code true} if this queue contains the specified element. |
| 349 | * More formally, returns {@code true} if and only if this queue contains |
| 350 | * at least one element {@code e} such that {@code o.equals(e)}. |
| 351 | * |
| 352 | * @param o object to be checked for containment in this queue |
| 353 | * @return <tt>true</tt> if this queue contains the specified element |
| 354 | */ |
| 355 | public boolean contains(Object o) { |
| 356 | final ReentrantLock lock = this.lock; |
| 357 | lock.lock(); |
| 358 | try { |
| 359 | return q.contains(o); |
| 360 | } finally { |
| 361 | lock.unlock(); |
| 362 | } |
| 363 | } |
| 364 | |
| 365 | /** |
| 366 | * Returns an array containing all of the elements in this queue. |
| 367 | * The returned array elements are in no particular order. |
| 368 | * |
| 369 | * <p>The returned array will be "safe" in that no references to it are |
| 370 | * maintained by this queue. (In other words, this method must allocate |
| 371 | * a new array). The caller is thus free to modify the returned array. |
| 372 | * |
| 373 | * <p>This method acts as bridge between array-based and collection-based |
| 374 | * APIs. |
| 375 | * |
| 376 | * @return an array containing all of the elements in this queue |
| 377 | */ |
| 378 | public Object[] toArray() { |
| 379 | final ReentrantLock lock = this.lock; |
| 380 | lock.lock(); |
| 381 | try { |
| 382 | return q.toArray(); |
| 383 | } finally { |
| 384 | lock.unlock(); |
| 385 | } |
| 386 | } |
| 387 | |
| 388 | |
| 389 | public String toString() { |
| 390 | final ReentrantLock lock = this.lock; |
| 391 | lock.lock(); |
| 392 | try { |
| 393 | return q.toString(); |
| 394 | } finally { |
| 395 | lock.unlock(); |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | /** |
| 400 | * @throws UnsupportedOperationException {@inheritDoc} |
| 401 | * @throws ClassCastException {@inheritDoc} |
| 402 | * @throws NullPointerException {@inheritDoc} |
| 403 | * @throws IllegalArgumentException {@inheritDoc} |
| 404 | */ |
| 405 | public int drainTo(Collection<? super E> c) { |
| 406 | if (c == null) |
| 407 | throw new NullPointerException(); |
| 408 | if (c == this) |
| 409 | throw new IllegalArgumentException(); |
| 410 | final ReentrantLock lock = this.lock; |
| 411 | lock.lock(); |
| 412 | try { |
| 413 | int n = 0; |
| 414 | E e; |
| 415 | while ( (e = q.poll()) != null) { |
| 416 | c.add(e); |
| 417 | ++n; |
| 418 | } |
| 419 | return n; |
| 420 | } finally { |
| 421 | lock.unlock(); |
| 422 | } |
| 423 | } |
| 424 | |
| 425 | /** |
| 426 | * @throws UnsupportedOperationException {@inheritDoc} |
| 427 | * @throws ClassCastException {@inheritDoc} |
| 428 | * @throws NullPointerException {@inheritDoc} |
| 429 | * @throws IllegalArgumentException {@inheritDoc} |
| 430 | */ |
| 431 | public int drainTo(Collection<? super E> c, int maxElements) { |
| 432 | if (c == null) |
| 433 | throw new NullPointerException(); |
| 434 | if (c == this) |
| 435 | throw new IllegalArgumentException(); |
| 436 | if (maxElements <= 0) |
| 437 | return 0; |
| 438 | final ReentrantLock lock = this.lock; |
| 439 | lock.lock(); |
| 440 | try { |
| 441 | int n = 0; |
| 442 | E e; |
| 443 | while (n < maxElements && (e = q.poll()) != null) { |
| 444 | c.add(e); |
| 445 | ++n; |
| 446 | } |
| 447 | return n; |
| 448 | } finally { |
| 449 | lock.unlock(); |
| 450 | } |
| 451 | } |
| 452 | |
| 453 | /** |
| 454 | * Atomically removes all of the elements from this queue. |
| 455 | * The queue will be empty after this call returns. |
| 456 | */ |
| 457 | public void clear() { |
| 458 | final ReentrantLock lock = this.lock; |
| 459 | lock.lock(); |
| 460 | try { |
| 461 | q.clear(); |
| 462 | } finally { |
| 463 | lock.unlock(); |
| 464 | } |
| 465 | } |
| 466 | |
| 467 | /** |
| 468 | * Returns an array containing all of the elements in this queue; the |
| 469 | * runtime type of the returned array is that of the specified array. |
| 470 | * The returned array elements are in no particular order. |
| 471 | * If the queue fits in the specified array, it is returned therein. |
| 472 | * Otherwise, a new array is allocated with the runtime type of the |
| 473 | * specified array and the size of this queue. |
| 474 | * |
| 475 | * <p>If this queue fits in the specified array with room to spare |
| 476 | * (i.e., the array has more elements than this queue), the element in |
| 477 | * the array immediately following the end of the queue is set to |
| 478 | * <tt>null</tt>. |
| 479 | * |
| 480 | * <p>Like the {@link #toArray()} method, this method acts as bridge between |
| 481 | * array-based and collection-based APIs. Further, this method allows |
| 482 | * precise control over the runtime type of the output array, and may, |
| 483 | * under certain circumstances, be used to save allocation costs. |
| 484 | * |
| 485 | * <p>Suppose <tt>x</tt> is a queue known to contain only strings. |
| 486 | * The following code can be used to dump the queue into a newly |
| 487 | * allocated array of <tt>String</tt>: |
| 488 | * |
| 489 | * <pre> |
| 490 | * String[] y = x.toArray(new String[0]);</pre> |
| 491 | * |
| 492 | * Note that <tt>toArray(new Object[0])</tt> is identical in function to |
| 493 | * <tt>toArray()</tt>. |
| 494 | * |
| 495 | * @param a the array into which the elements of the queue are to |
| 496 | * be stored, if it is big enough; otherwise, a new array of the |
| 497 | * same runtime type is allocated for this purpose |
| 498 | * @return an array containing all of the elements in this queue |
| 499 | * @throws ArrayStoreException if the runtime type of the specified array |
| 500 | * is not a supertype of the runtime type of every element in |
| 501 | * this queue |
| 502 | * @throws NullPointerException if the specified array is null |
| 503 | */ |
| 504 | public <T> T[] toArray(T[] a) { |
| 505 | final ReentrantLock lock = this.lock; |
| 506 | lock.lock(); |
| 507 | try { |
| 508 | return q.toArray(a); |
| 509 | } finally { |
| 510 | lock.unlock(); |
| 511 | } |
| 512 | } |
| 513 | |
| 514 | /** |
| 515 | * Returns an iterator over the elements in this queue. The |
| 516 | * iterator does not return the elements in any particular order. |
| 517 | * The returned <tt>Iterator</tt> is a "weakly consistent" |
| 518 | * iterator that will never throw {@link |
| 519 | * ConcurrentModificationException}, and guarantees to traverse |
| 520 | * elements as they existed upon construction of the iterator, and |
| 521 | * may (but is not guaranteed to) reflect any modifications |
| 522 | * subsequent to construction. |
| 523 | * |
| 524 | * @return an iterator over the elements in this queue |
| 525 | */ |
| 526 | public Iterator<E> iterator() { |
| 527 | return new Itr(toArray()); |
| 528 | } |
| 529 | |
| 530 | /** |
| 531 | * Snapshot iterator that works off copy of underlying q array. |
| 532 | */ |
| 533 | private class Itr implements Iterator<E> { |
| 534 | final Object[] array; // Array of all elements |
| 535 | int cursor; // index of next element to return; |
| 536 | int lastRet; // index of last element, or -1 if no such |
| 537 | |
| 538 | Itr(Object[] array) { |
| 539 | lastRet = -1; |
| 540 | this.array = array; |
| 541 | } |
| 542 | |
| 543 | public boolean hasNext() { |
| 544 | return cursor < array.length; |
| 545 | } |
| 546 | |
| 547 | public E next() { |
| 548 | if (cursor >= array.length) |
| 549 | throw new NoSuchElementException(); |
| 550 | lastRet = cursor; |
| 551 | return (E)array[cursor++]; |
| 552 | } |
| 553 | |
| 554 | public void remove() { |
| 555 | if (lastRet < 0) |
| 556 | throw new IllegalStateException(); |
| 557 | Object x = array[lastRet]; |
| 558 | lastRet = -1; |
| 559 | // Traverse underlying queue to find == element, |
| 560 | // not just a .equals element. |
| 561 | lock.lock(); |
| 562 | try { |
| 563 | for (Iterator it = q.iterator(); it.hasNext(); ) { |
| 564 | if (it.next() == x) { |
| 565 | it.remove(); |
| 566 | return; |
| 567 | } |
| 568 | } |
| 569 | } finally { |
| 570 | lock.unlock(); |
| 571 | } |
| 572 | } |
| 573 | } |
| 574 | |
| 575 | /** |
| 576 | * Saves the state to a stream (that is, serializes it). This |
| 577 | * merely wraps default serialization within lock. The |
| 578 | * serialization strategy for items is left to underlying |
| 579 | * Queue. Note that locking is not needed on deserialization, so |
| 580 | * readObject is not defined, just relying on default. |
| 581 | */ |
| 582 | private void writeObject(java.io.ObjectOutputStream s) |
| 583 | throws java.io.IOException { |
| 584 | lock.lock(); |
| 585 | try { |
| 586 | s.defaultWriteObject(); |
| 587 | } finally { |
| 588 | lock.unlock(); |
| 589 | } |
| 590 | } |
| 591 | |
| 592 | } |