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| 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. Oracle designates this | ||
| 7 | * particular file as subject to the "Classpath" exception as provided | ||
| 8 | * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 21 | * or visit www.oracle.com if you need additional information or have any | ||
| 22 | * 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/publicdomain/zero/1.0/ | ||
| 34 | */ | ||
| 35 | |||
| 36 | |||
| 37 | package java.util.concurrent; | ||
| 38 | import java.util.concurrent.locks.*; | ||
| 39 | import java.util.*; | ||
| 40 | |||
| 41 | /** | ||
| 42 | * An unbounded {@linkplain BlockingQueue blocking queue} of | ||
| 43 | * <tt>Delayed</tt> elements, in which an element can only be taken | ||
| 44 | * when its delay has expired. The <em>head</em> of the queue is that | ||
| 45 | * <tt>Delayed</tt> element whose delay expired furthest in the | ||
| 46 | * past. If no delay has expired there is no head and <tt>poll</tt> | ||
| 47 | * will return <tt>null</tt>. Expiration occurs when an element's | ||
| 48 | * <tt>getDelay(TimeUnit.NANOSECONDS)</tt> method returns a value less | ||
| 49 | * than or equal to zero. Even though unexpired elements cannot be | ||
| 50 | * removed using <tt>take</tt> or <tt>poll</tt>, they are otherwise | ||
| 51 | * treated as normal elements. For example, the <tt>size</tt> method | ||
| 52 | * returns the count of both expired and unexpired elements. | ||
| 53 | * This queue does not permit null elements. | ||
| 54 | * | ||
| 55 | * <p>This class and its iterator implement all of the | ||
| 56 | * <em>optional</em> methods of the {@link Collection} and {@link | ||
| 57 | * Iterator} interfaces. | ||
| 58 | * | ||
| 59 | * <p>This class is a member of the | ||
| 60 | * <a href="{@docRoot}/../technotes/guides/collections/index.html"> | ||
| 61 | * Java Collections Framework</a>. | ||
| 62 | * | ||
| 63 | * @since 1.5 | ||
| 64 | * @author Doug Lea | ||
| 65 | * @param <E> the type of elements held in this collection | ||
| 66 | */ | ||
| 67 | |||
| 68 | public class DelayQueue<E extends Delayed> extends AbstractQueue<E> | ||
| 69 | implements BlockingQueue<E> { | ||
| 70 | |||
| 71 | private transient final ReentrantLock lock = new ReentrantLock(); | ||
| 72 | private final PriorityQueue<E> q = new PriorityQueue<E>(); | ||
| 73 | |||
| 74 | /** | ||
| 75 | * Thread designated to wait for the element at the head of | ||
| 76 | * the queue. This variant of the Leader-Follower pattern | ||
| 77 | * (http://www.cs.wustl.edu/~schmidt/POSA/POSA2/) serves to | ||
| 78 | * minimize unnecessary timed waiting. When a thread becomes | ||
| 79 | * the leader, it waits only for the next delay to elapse, but | ||
| 80 | * other threads await indefinitely. The leader thread must | ||
| 81 | * signal some other thread before returning from take() or | ||
| 82 | * poll(...), unless some other thread becomes leader in the | ||
| 83 | * interim. Whenever the head of the queue is replaced with | ||
| 84 | * an element with an earlier expiration time, the leader | ||
| 85 | * field is invalidated by being reset to null, and some | ||
| 86 | * waiting thread, but not necessarily the current leader, is | ||
| 87 | * signalled. So waiting threads must be prepared to acquire | ||
| 88 | * and lose leadership while waiting. | ||
| 89 | */ | ||
| 90 | private Thread leader = null; | ||
| 91 | |||
| 92 | /** | ||
| 93 | * Condition signalled when a newer element becomes available | ||
| 94 | * at the head of the queue or a new thread may need to | ||
| 95 | * become leader. | ||
| 96 | */ | ||
| 97 | private final Condition available = lock.newCondition(); | ||
| 98 | |||
| 99 | /** | ||
| 100 | * Creates a new <tt>DelayQueue</tt> that is initially empty. | ||
| 101 | */ | ||
| 102 | public DelayQueue() {} | ||
| 103 | |||
| 104 | /** | ||
| 105 | * Creates a <tt>DelayQueue</tt> initially containing the elements of the | ||
| 106 | * given collection of {@link Delayed} instances. | ||
| 107 | * | ||
| 108 | * @param c the collection of elements to initially contain | ||
| 109 | * @throws NullPointerException if the specified collection or any | ||
| 110 | * of its elements are null | ||
| 111 | */ | ||
| 112 | public DelayQueue(Collection<? extends E> c) { | ||
| 113 | this.addAll(c); | ||
| 114 | } | ||
| 115 | |||
| 116 | /** | ||
| 117 | * Inserts the specified element into this delay queue. | ||
| 118 | * | ||
| 119 | * @param e the element to add | ||
| 120 | * @return <tt>true</tt> (as specified by {@link Collection#add}) | ||
| 121 | * @throws NullPointerException if the specified element is null | ||
| 122 | */ | ||
| 123 | public boolean add(E e) { | ||
| 124 | return offer(e); | ||
| 125 | } | ||
| 126 | |||
| 127 | /** | ||
| 128 | * Inserts the specified element into this delay queue. | ||
| 129 | * | ||
| 130 | * @param e the element to add | ||
| 131 | * @return <tt>true</tt> | ||
| 132 | * @throws NullPointerException if the specified element is null | ||
| 133 | */ | ||
| 134 | public boolean offer(E e) { | ||
| 135 | final ReentrantLock lock = this.lock; | ||
| 136 | lock.lock(); | ||
| 137 | try { | ||
| 138 | q.offer(e); | ||
| 139 | if (q.peek() == e) { | ||
| 140 | leader = null; | ||
| 141 | available.signal(); | ||
| 142 | } | ||
| 143 | return true; | ||
| 144 | } finally { | ||
| 145 | lock.unlock(); | ||
| 146 | } | ||
| 147 | } | ||
| 148 | |||
| 149 | /** | ||
| 150 | * Inserts the specified element into this delay queue. As the queue is | ||
| 151 | * unbounded this method will never block. | ||
| 152 | * | ||
| 153 | * @param e the element to add | ||
| 154 | * @throws NullPointerException {@inheritDoc} | ||
| 155 | */ | ||
| 156 | public void put(E e) { | ||
| 157 | offer(e); | ||
| 158 | } | ||
| 159 | |||
| 160 | /** | ||
| 161 | * Inserts the specified element into this delay queue. As the queue is | ||
| 162 | * unbounded this method will never block. | ||
| 163 | * | ||
| 164 | * @param e the element to add | ||
| 165 | * @param timeout This parameter is ignored as the method never blocks | ||
| 166 | * @param unit This parameter is ignored as the method never blocks | ||
| 167 | * @return <tt>true</tt> | ||
| 168 | * @throws NullPointerException {@inheritDoc} | ||
| 169 | */ | ||
| 170 | public boolean offer(E e, long timeout, TimeUnit unit) { | ||
| 171 | return offer(e); | ||
| 172 | } | ||
| 173 | |||
| 174 | /** | ||
| 175 | * Retrieves and removes the head of this queue, or returns <tt>null</tt> | ||
| 176 | * if this queue has no elements with an expired delay. | ||
| 177 | * | ||
| 178 | * @return the head of this queue, or <tt>null</tt> if this | ||
| 179 | * queue has no elements with an expired delay | ||
| 180 | */ | ||
| 181 | public E poll() { | ||
| 182 | final ReentrantLock lock = this.lock; | ||
| 183 | lock.lock(); | ||
| 184 | try { | ||
| 185 | E first = q.peek(); | ||
| 186 | if (first == null || first.getDelay(TimeUnit.NANOSECONDS) > 0) | ||
| 187 | return null; | ||
| 188 | else | ||
| 189 | return q.poll(); | ||
| 190 | } finally { | ||
| 191 | lock.unlock(); | ||
| 192 | } | ||
| 193 | } | ||
| 194 | |||
| 195 | /** | ||
| 196 | * Retrieves and removes the head of this queue, waiting if necessary | ||
| 197 | * until an element with an expired delay is available on this queue. | ||
| 198 | * | ||
| 199 | * @return the head of this queue | ||
| 200 | * @throws InterruptedException {@inheritDoc} | ||
| 201 | */ | ||
| 202 | public E take() throws InterruptedException { | ||
| 203 | final ReentrantLock lock = this.lock; | ||
| 204 | lock.lockInterruptibly(); | ||
| 205 | try { | ||
| 206 | for (;;) { | ||
| 207 | E first = q.peek(); | ||
| 208 | if (first == null) | ||
| 209 | available.await(); | ||
| 210 | else { | ||
| 211 | long delay = first.getDelay(TimeUnit.NANOSECONDS); | ||
| 212 | if (delay <= 0) | ||
| 213 | return q.poll(); | ||
| 214 | else if (leader != null) | ||
| 215 | available.await(); | ||
| 216 | else { | ||
| 217 | Thread thisThread = Thread.currentThread(); | ||
| 218 | leader = thisThread; | ||
| 219 | try { | ||
| 220 | available.awaitNanos(delay); | ||
| 221 | } finally { | ||
| 222 | if (leader == thisThread) | ||
| 223 | leader = null; | ||
| 224 | } | ||
| 225 | } | ||
| 226 | } | ||
| 227 | } | ||
| 228 | } finally { | ||
| 229 | if (leader == null && q.peek() != null) | ||
| 230 | available.signal(); | ||
| 231 | lock.unlock(); | ||
| 232 | } | ||
| 233 | } | ||
| 234 | |||
| 235 | /** | ||
| 236 | * Retrieves and removes the head of this queue, waiting if necessary | ||
| 237 | * until an element with an expired delay is available on this queue, | ||
| 238 | * or the specified wait time expires. | ||
| 239 | * | ||
| 240 | * @return the head of this queue, or <tt>null</tt> if the | ||
| 241 | * specified waiting time elapses before an element with | ||
| 242 | * an expired delay becomes available | ||
| 243 | * @throws InterruptedException {@inheritDoc} | ||
| 244 | */ | ||
| 245 | public E poll(long timeout, TimeUnit unit) throws InterruptedException { | ||
| 246 | long nanos = unit.toNanos(timeout); | ||
| 247 | final ReentrantLock lock = this.lock; | ||
| 248 | lock.lockInterruptibly(); | ||
| 249 | try { | ||
| 250 | for (;;) { | ||
| 251 | E first = q.peek(); | ||
| 252 | if (first == null) { | ||
| 253 | if (nanos <= 0) | ||
| 254 | return null; | ||
| 255 | else | ||
| 256 | nanos = available.awaitNanos(nanos); | ||
| 257 | } else { | ||
| 258 | long delay = first.getDelay(TimeUnit.NANOSECONDS); | ||
| 259 | if (delay <= 0) | ||
| 260 | return q.poll(); | ||
| 261 | if (nanos <= 0) | ||
| 262 | return null; | ||
| 263 | if (nanos < delay || leader != null) | ||
| 264 | nanos = available.awaitNanos(nanos); | ||
| 265 | else { | ||
| 266 | Thread thisThread = Thread.currentThread(); | ||
| 267 | leader = thisThread; | ||
| 268 | try { | ||
| 269 | long timeLeft = available.awaitNanos(delay); | ||
| 270 | nanos -= delay - timeLeft; | ||
| 271 | } finally { | ||
| 272 | if (leader == thisThread) | ||
| 273 | leader = null; | ||
| 274 | } | ||
| 275 | } | ||
| 276 | } | ||
| 277 | } | ||
| 278 | } finally { | ||
| 279 | if (leader == null && q.peek() != null) | ||
| 280 | available.signal(); | ||
| 281 | lock.unlock(); | ||
| 282 | } | ||
| 283 | } | ||
| 284 | |||
| 285 | /** | ||
| 286 | * Retrieves, but does not remove, the head of this queue, or | ||
| 287 | * returns <tt>null</tt> if this queue is empty. Unlike | ||
| 288 | * <tt>poll</tt>, if no expired elements are available in the queue, | ||
| 289 | * this method returns the element that will expire next, | ||
| 290 | * if one exists. | ||
| 291 | * | ||
| 292 | * @return the head of this queue, or <tt>null</tt> if this | ||
| 293 | * queue is empty. | ||
| 294 | */ | ||
| 295 | public E peek() { | ||
| 296 | final ReentrantLock lock = this.lock; | ||
| 297 | lock.lock(); | ||
| 298 | try { | ||
| 299 | return q.peek(); | ||
| 300 | } finally { | ||
| 301 | lock.unlock(); | ||
| 302 | } | ||
| 303 | } | ||
| 304 | |||
| 305 | public int size() { | ||
| 306 | final ReentrantLock lock = this.lock; | ||
| 307 | lock.lock(); | ||
| 308 | try { | ||
| 309 | return q.size(); | ||
| 310 | } finally { | ||
| 311 | lock.unlock(); | ||
| 312 | } | ||
| 313 | } | ||
| 314 | |||
| 315 | /** | ||
| 316 | * @throws UnsupportedOperationException {@inheritDoc} | ||
| 317 | * @throws ClassCastException {@inheritDoc} | ||
| 318 | * @throws NullPointerException {@inheritDoc} | ||
| 319 | * @throws IllegalArgumentException {@inheritDoc} | ||
| 320 | */ | ||
| 321 | public int drainTo(Collection<? super E> c) { | ||
| 322 | if (c == null) | ||
| 323 | throw new NullPointerException(); | ||
| 324 | if (c == this) | ||
| 325 | throw new IllegalArgumentException(); | ||
| 326 | final ReentrantLock lock = this.lock; | ||
| 327 | lock.lock(); | ||
| 328 | try { | ||
| 329 | int n = 0; | ||
| 330 | for (;;) { | ||
| 331 | E first = q.peek(); | ||
| 332 | if (first == null || first.getDelay(TimeUnit.NANOSECONDS) > 0) | ||
| 333 | break; | ||
| 334 | c.add(q.poll()); | ||
| 335 | ++n; | ||
| 336 | } | ||
| 337 | return n; | ||
| 338 | } finally { | ||
| 339 | lock.unlock(); | ||
| 340 | } | ||
| 341 | } | ||
| 342 | |||
| 343 | /** | ||
| 344 | * @throws UnsupportedOperationException {@inheritDoc} | ||
| 345 | * @throws ClassCastException {@inheritDoc} | ||
| 346 | * @throws NullPointerException {@inheritDoc} | ||
| 347 | * @throws IllegalArgumentException {@inheritDoc} | ||
| 348 | */ | ||
| 349 | public int drainTo(Collection<? super E> c, int maxElements) { | ||
| 350 | if (c == null) | ||
| 351 | throw new NullPointerException(); | ||
| 352 | if (c == this) | ||
| 353 | throw new IllegalArgumentException(); | ||
| 354 | if (maxElements <= 0) | ||
| 355 | return 0; | ||
| 356 | final ReentrantLock lock = this.lock; | ||
| 357 | lock.lock(); | ||
| 358 | try { | ||
| 359 | int n = 0; | ||
| 360 | while (n < maxElements) { | ||
| 361 | E first = q.peek(); | ||
| 362 | if (first == null || first.getDelay(TimeUnit.NANOSECONDS) > 0) | ||
| 363 | break; | ||
| 364 | c.add(q.poll()); | ||
| 365 | ++n; | ||
| 366 | } | ||
| 367 | return n; | ||
| 368 | } finally { | ||
| 369 | lock.unlock(); | ||
| 370 | } | ||
| 371 | } | ||
| 372 | |||
| 373 | /** | ||
| 374 | * Atomically removes all of the elements from this delay queue. | ||
| 375 | * The queue will be empty after this call returns. | ||
| 376 | * Elements with an unexpired delay are not waited for; they are | ||
| 377 | * simply discarded from the queue. | ||
| 378 | */ | ||
| 379 | public void clear() { | ||
| 380 | final ReentrantLock lock = this.lock; | ||
| 381 | lock.lock(); | ||
| 382 | try { | ||
| 383 | q.clear(); | ||
| 384 | } finally { | ||
| 385 | lock.unlock(); | ||
| 386 | } | ||
| 387 | } | ||
| 388 | |||
| 389 | /** | ||
| 390 | * Always returns <tt>Integer.MAX_VALUE</tt> because | ||
| 391 | * a <tt>DelayQueue</tt> is not capacity constrained. | ||
| 392 | * | ||
| 393 | * @return <tt>Integer.MAX_VALUE</tt> | ||
| 394 | */ | ||
| 395 | public int remainingCapacity() { | ||
| 396 | return Integer.MAX_VALUE; | ||
| 397 | } | ||
| 398 | |||
| 399 | /** | ||
| 400 | * Returns an array containing all of the elements in this queue. | ||
| 401 | * The returned array elements are in no particular order. | ||
| 402 | * | ||
| 403 | * <p>The returned array will be "safe" in that no references to it are | ||
| 404 | * maintained by this queue. (In other words, this method must allocate | ||
| 405 | * a new array). The caller is thus free to modify the returned array. | ||
| 406 | * | ||
| 407 | * <p>This method acts as bridge between array-based and collection-based | ||
| 408 | * APIs. | ||
| 409 | * | ||
| 410 | * @return an array containing all of the elements in this queue | ||
| 411 | */ | ||
| 412 | public Object[] toArray() { | ||
| 413 | final ReentrantLock lock = this.lock; | ||
| 414 | lock.lock(); | ||
| 415 | try { | ||
| 416 | return q.toArray(); | ||
| 417 | } finally { | ||
| 418 | lock.unlock(); | ||
| 419 | } | ||
| 420 | } | ||
| 421 | |||
| 422 | /** | ||
| 423 | * Returns an array containing all of the elements in this queue; the | ||
| 424 | * runtime type of the returned array is that of the specified array. | ||
| 425 | * The returned array elements are in no particular order. | ||
| 426 | * If the queue fits in the specified array, it is returned therein. | ||
| 427 | * Otherwise, a new array is allocated with the runtime type of the | ||
| 428 | * specified array and the size of this queue. | ||
| 429 | * | ||
| 430 | * <p>If this queue fits in the specified array with room to spare | ||
| 431 | * (i.e., the array has more elements than this queue), the element in | ||
| 432 | * the array immediately following the end of the queue is set to | ||
| 433 | * <tt>null</tt>. | ||
| 434 | * | ||
| 435 | * <p>Like the {@link #toArray()} method, this method acts as bridge between | ||
| 436 | * array-based and collection-based APIs. Further, this method allows | ||
| 437 | * precise control over the runtime type of the output array, and may, | ||
| 438 | * under certain circumstances, be used to save allocation costs. | ||
| 439 | * | ||
| 440 | * <p>The following code can be used to dump a delay queue into a newly | ||
| 441 | * allocated array of <tt>Delayed</tt>: | ||
| 442 | * | ||
| 443 | * <pre> | ||
| 444 | * Delayed[] a = q.toArray(new Delayed[0]);</pre> | ||
| 445 | * | ||
| 446 | * Note that <tt>toArray(new Object[0])</tt> is identical in function to | ||
| 447 | * <tt>toArray()</tt>. | ||
| 448 | * | ||
| 449 | * @param a the array into which the elements of the queue are to | ||
| 450 | * be stored, if it is big enough; otherwise, a new array of the | ||
| 451 | * same runtime type is allocated for this purpose | ||
| 452 | * @return an array containing all of the elements in this queue | ||
| 453 | * @throws ArrayStoreException if the runtime type of the specified array | ||
| 454 | * is not a supertype of the runtime type of every element in | ||
| 455 | * this queue | ||
| 456 | * @throws NullPointerException if the specified array is null | ||
| 457 | */ | ||
| 458 | public <T> T[] toArray(T[] a) { | ||
| 459 | final ReentrantLock lock = this.lock; | ||
| 460 | lock.lock(); | ||
| 461 | try { | ||
| 462 | return q.toArray(a); | ||
| 463 | } finally { | ||
| 464 | lock.unlock(); | ||
| 465 | } | ||
| 466 | } | ||
| 467 | |||
| 468 | /** | ||
| 469 | * Removes a single instance of the specified element from this | ||
| 470 | * queue, if it is present, whether or not it has expired. | ||
| 471 | */ | ||
| 472 | public boolean remove(Object o) { | ||
| 473 | final ReentrantLock lock = this.lock; | ||
| 474 | lock.lock(); | ||
| 475 | try { | ||
| 476 | return q.remove(o); | ||
| 477 | } finally { | ||
| 478 | lock.unlock(); | ||
| 479 | } | ||
| 480 | } | ||
| 481 | |||
| 482 | /** | ||
| 483 | * Returns an iterator over all the elements (both expired and | ||
| 484 | * unexpired) in this queue. The iterator does not return the | ||
| 485 | * elements in any particular order. | ||
| 486 | * | ||
| 487 | * <p>The returned iterator is a "weakly consistent" iterator that | ||
| 488 | * will never throw {@link java.util.ConcurrentModificationException | ||
| 489 | * ConcurrentModificationException}, and guarantees to traverse | ||
| 490 | * elements as they existed upon construction of the iterator, and | ||
| 491 | * may (but is not guaranteed to) reflect any modifications | ||
| 492 | * subsequent to construction. | ||
| 493 | * | ||
| 494 | * @return an iterator over the elements in this queue | ||
| 495 | */ | ||
| 496 | public Iterator<E> iterator() { | ||
| 497 | return new Itr(toArray()); | ||
| 498 | } | ||
| 499 | |||
| 500 | /** | ||
| 501 | * Snapshot iterator that works off copy of underlying q array. | ||
| 502 | */ | ||
| 503 | private class Itr implements Iterator<E> { | ||
| 504 | final Object[] array; // Array of all elements | ||
| 505 | int cursor; // index of next element to return; | ||
| 506 | int lastRet; // index of last element, or -1 if no such | ||
| 507 | |||
| 508 | Itr(Object[] array) { | ||
| 509 | lastRet = -1; | ||
| 510 | this.array = array; | ||
| 511 | } | ||
| 512 | |||
| 513 | public boolean hasNext() { | ||
| 514 | return cursor < array.length; | ||
| 515 | } | ||
| 516 | |||
| 517 | @SuppressWarnings("unchecked") | ||
| 518 | public E next() { | ||
| 519 | if (cursor >= array.length) | ||
| 520 | throw new NoSuchElementException(); | ||
| 521 | lastRet = cursor; | ||
| 522 | return (E)array[cursor++]; | ||
| 523 | } | ||
| 524 | |||
| 525 | public void remove() { | ||
| 526 | if (lastRet < 0) | ||
| 527 | throw new IllegalStateException(); | ||
| 528 | Object x = array[lastRet]; | ||
| 529 | lastRet = -1; | ||
| 530 | // Traverse underlying queue to find == element, | ||
| 531 | // not just a .equals element. | ||
| 532 | lock.lock(); | ||
| 533 | try { | ||
| 534 | for (Iterator it = q.iterator(); it.hasNext(); ) { | ||
| 535 | if (it.next() == x) { | ||
| 536 | it.remove(); | ||
| 537 | return; | ||
| 538 | } | ||
| 539 | } | ||
| 540 | } finally { | ||
| 541 | lock.unlock(); | ||
| 542 | } | ||
| 543 | } | ||
| 544 | } | ||
| 545 | |||
| 546 | } | ||