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root/jsr166/jsr166/src/test/tck/DelayQueueTest.java
Revision: 1.76
Committed: Tue Oct 6 00:03:55 2015 UTC (8 years, 7 months ago) by jsr166
Branch: MAIN
Changes since 1.75: +6 -2 lines
Log Message:
improve testInterruptedTimedPoll

File Contents

# Content
1 /*
2 * Written by Doug Lea with assistance from members of JCP JSR-166
3 * Expert Group and released to the public domain, as explained at
4 * http://creativecommons.org/publicdomain/zero/1.0/
5 * Other contributors include Andrew Wright, Jeffrey Hayes,
6 * Pat Fisher, Mike Judd.
7 */
8
9 import static java.util.concurrent.TimeUnit.MILLISECONDS;
10
11 import java.util.ArrayList;
12 import java.util.Arrays;
13 import java.util.Collection;
14 import java.util.Iterator;
15 import java.util.NoSuchElementException;
16 import java.util.concurrent.BlockingQueue;
17 import java.util.concurrent.CountDownLatch;
18 import java.util.concurrent.Delayed;
19 import java.util.concurrent.DelayQueue;
20 import java.util.concurrent.Executors;
21 import java.util.concurrent.ExecutorService;
22 import java.util.concurrent.TimeUnit;
23
24 import junit.framework.Test;
25
26 public class DelayQueueTest extends JSR166TestCase {
27
28 public static class Generic extends BlockingQueueTest {
29 protected BlockingQueue emptyCollection() {
30 return new DelayQueue();
31 }
32 protected PDelay makeElement(int i) {
33 return new PDelay(i);
34 }
35 }
36
37 public static void main(String[] args) {
38 main(suite(), args);
39 }
40
41 public static Test suite() {
42 return newTestSuite(DelayQueueTest.class,
43 new Generic().testSuite());
44 }
45
46 /**
47 * A delayed implementation for testing.
48 * Most tests use Pseudodelays, where delays are all elapsed
49 * (so, no blocking solely for delays) but are still ordered
50 */
51 static class PDelay implements Delayed {
52 int pseudodelay;
53 PDelay(int i) { pseudodelay = i; }
54 public int compareTo(PDelay other) {
55 int a = this.pseudodelay;
56 int b = other.pseudodelay;
57 return (a < b) ? -1 : (a > b) ? 1 : 0;
58 }
59 public int compareTo(Delayed y) {
60 return compareTo((PDelay)y);
61 }
62 public boolean equals(Object other) {
63 return (other instanceof PDelay) &&
64 this.pseudodelay == ((PDelay)other).pseudodelay;
65 }
66 // suppress [overrides] javac warning
67 public int hashCode() { return pseudodelay; }
68 public long getDelay(TimeUnit ignore) {
69 return Integer.MIN_VALUE + pseudodelay;
70 }
71 public String toString() {
72 return String.valueOf(pseudodelay);
73 }
74 }
75
76 /**
77 * Delayed implementation that actually delays
78 */
79 static class NanoDelay implements Delayed {
80 long trigger;
81 NanoDelay(long i) {
82 trigger = System.nanoTime() + i;
83 }
84 public int compareTo(NanoDelay y) {
85 long i = trigger;
86 long j = y.trigger;
87 if (i < j) return -1;
88 if (i > j) return 1;
89 return 0;
90 }
91
92 public int compareTo(Delayed y) {
93 return compareTo((NanoDelay)y);
94 }
95
96 public boolean equals(Object other) {
97 return equals((NanoDelay)other);
98 }
99 public boolean equals(NanoDelay other) {
100 return other.trigger == trigger;
101 }
102
103 // suppress [overrides] javac warning
104 public int hashCode() { return (int) trigger; }
105
106 public long getDelay(TimeUnit unit) {
107 long n = trigger - System.nanoTime();
108 return unit.convert(n, TimeUnit.NANOSECONDS);
109 }
110
111 public long getTriggerTime() {
112 return trigger;
113 }
114
115 public String toString() {
116 return String.valueOf(trigger);
117 }
118 }
119
120 /**
121 * Returns a new queue of given size containing consecutive
122 * PDelays 0 ... n.
123 */
124 private DelayQueue<PDelay> populatedQueue(int n) {
125 DelayQueue<PDelay> q = new DelayQueue<PDelay>();
126 assertTrue(q.isEmpty());
127 for (int i = n - 1; i >= 0; i -= 2)
128 assertTrue(q.offer(new PDelay(i)));
129 for (int i = (n & 1); i < n; i += 2)
130 assertTrue(q.offer(new PDelay(i)));
131 assertFalse(q.isEmpty());
132 assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
133 assertEquals(n, q.size());
134 return q;
135 }
136
137 /**
138 * A new queue has unbounded capacity
139 */
140 public void testConstructor1() {
141 assertEquals(Integer.MAX_VALUE, new DelayQueue().remainingCapacity());
142 }
143
144 /**
145 * Initializing from null Collection throws NPE
146 */
147 public void testConstructor3() {
148 try {
149 new DelayQueue(null);
150 shouldThrow();
151 } catch (NullPointerException success) {}
152 }
153
154 /**
155 * Initializing from Collection of null elements throws NPE
156 */
157 public void testConstructor4() {
158 try {
159 new DelayQueue(Arrays.asList(new PDelay[SIZE]));
160 shouldThrow();
161 } catch (NullPointerException success) {}
162 }
163
164 /**
165 * Initializing from Collection with some null elements throws NPE
166 */
167 public void testConstructor5() {
168 PDelay[] a = new PDelay[SIZE];
169 for (int i = 0; i < SIZE - 1; ++i)
170 a[i] = new PDelay(i);
171 try {
172 new DelayQueue(Arrays.asList(a));
173 shouldThrow();
174 } catch (NullPointerException success) {}
175 }
176
177 /**
178 * Queue contains all elements of collection used to initialize
179 */
180 public void testConstructor6() {
181 PDelay[] ints = new PDelay[SIZE];
182 for (int i = 0; i < SIZE; ++i)
183 ints[i] = new PDelay(i);
184 DelayQueue q = new DelayQueue(Arrays.asList(ints));
185 for (int i = 0; i < SIZE; ++i)
186 assertEquals(ints[i], q.poll());
187 }
188
189 /**
190 * isEmpty is true before add, false after
191 */
192 public void testEmpty() {
193 DelayQueue q = new DelayQueue();
194 assertTrue(q.isEmpty());
195 assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
196 q.add(new PDelay(1));
197 assertFalse(q.isEmpty());
198 q.add(new PDelay(2));
199 q.remove();
200 q.remove();
201 assertTrue(q.isEmpty());
202 }
203
204 /**
205 * remainingCapacity() always returns Integer.MAX_VALUE
206 */
207 public void testRemainingCapacity() {
208 BlockingQueue q = populatedQueue(SIZE);
209 for (int i = 0; i < SIZE; ++i) {
210 assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
211 assertEquals(SIZE - i, q.size());
212 assertTrue(q.remove() instanceof PDelay);
213 }
214 for (int i = 0; i < SIZE; ++i) {
215 assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
216 assertEquals(i, q.size());
217 assertTrue(q.add(new PDelay(i)));
218 }
219 }
220
221 /**
222 * offer non-null succeeds
223 */
224 public void testOffer() {
225 DelayQueue q = new DelayQueue();
226 assertTrue(q.offer(new PDelay(0)));
227 assertTrue(q.offer(new PDelay(1)));
228 }
229
230 /**
231 * add succeeds
232 */
233 public void testAdd() {
234 DelayQueue q = new DelayQueue();
235 for (int i = 0; i < SIZE; ++i) {
236 assertEquals(i, q.size());
237 assertTrue(q.add(new PDelay(i)));
238 }
239 }
240
241 /**
242 * addAll(this) throws IAE
243 */
244 public void testAddAllSelf() {
245 DelayQueue q = populatedQueue(SIZE);
246 try {
247 q.addAll(q);
248 shouldThrow();
249 } catch (IllegalArgumentException success) {}
250 }
251
252 /**
253 * addAll of a collection with any null elements throws NPE after
254 * possibly adding some elements
255 */
256 public void testAddAll3() {
257 DelayQueue q = new DelayQueue();
258 PDelay[] a = new PDelay[SIZE];
259 for (int i = 0; i < SIZE - 1; ++i)
260 a[i] = new PDelay(i);
261 try {
262 q.addAll(Arrays.asList(a));
263 shouldThrow();
264 } catch (NullPointerException success) {}
265 }
266
267 /**
268 * Queue contains all elements of successful addAll
269 */
270 public void testAddAll5() {
271 PDelay[] empty = new PDelay[0];
272 PDelay[] ints = new PDelay[SIZE];
273 for (int i = SIZE - 1; i >= 0; --i)
274 ints[i] = new PDelay(i);
275 DelayQueue q = new DelayQueue();
276 assertFalse(q.addAll(Arrays.asList(empty)));
277 assertTrue(q.addAll(Arrays.asList(ints)));
278 for (int i = 0; i < SIZE; ++i)
279 assertEquals(ints[i], q.poll());
280 }
281
282 /**
283 * all elements successfully put are contained
284 */
285 public void testPut() {
286 DelayQueue q = new DelayQueue();
287 for (int i = 0; i < SIZE; ++i) {
288 PDelay x = new PDelay(i);
289 q.put(x);
290 assertTrue(q.contains(x));
291 }
292 assertEquals(SIZE, q.size());
293 }
294
295 /**
296 * put doesn't block waiting for take
297 */
298 public void testPutWithTake() throws InterruptedException {
299 final DelayQueue q = new DelayQueue();
300 Thread t = newStartedThread(new CheckedRunnable() {
301 public void realRun() {
302 q.put(new PDelay(0));
303 q.put(new PDelay(0));
304 q.put(new PDelay(0));
305 q.put(new PDelay(0));
306 }});
307
308 awaitTermination(t);
309 assertEquals(4, q.size());
310 }
311
312 /**
313 * timed offer does not time out
314 */
315 public void testTimedOffer() throws InterruptedException {
316 final DelayQueue q = new DelayQueue();
317 Thread t = newStartedThread(new CheckedRunnable() {
318 public void realRun() throws InterruptedException {
319 q.put(new PDelay(0));
320 q.put(new PDelay(0));
321 assertTrue(q.offer(new PDelay(0), SHORT_DELAY_MS, MILLISECONDS));
322 assertTrue(q.offer(new PDelay(0), LONG_DELAY_MS, MILLISECONDS));
323 }});
324
325 awaitTermination(t);
326 }
327
328 /**
329 * take retrieves elements in priority order
330 */
331 public void testTake() throws InterruptedException {
332 DelayQueue q = populatedQueue(SIZE);
333 for (int i = 0; i < SIZE; ++i) {
334 assertEquals(new PDelay(i), q.take());
335 }
336 }
337
338 /**
339 * Take removes existing elements until empty, then blocks interruptibly
340 */
341 public void testBlockingTake() throws InterruptedException {
342 final DelayQueue q = populatedQueue(SIZE);
343 final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
344 Thread t = newStartedThread(new CheckedRunnable() {
345 public void realRun() throws InterruptedException {
346 for (int i = 0; i < SIZE; ++i) {
347 assertEquals(new PDelay(i), ((PDelay)q.take()));
348 }
349
350 Thread.currentThread().interrupt();
351 try {
352 q.take();
353 shouldThrow();
354 } catch (InterruptedException success) {}
355 assertFalse(Thread.interrupted());
356
357 pleaseInterrupt.countDown();
358 try {
359 q.take();
360 shouldThrow();
361 } catch (InterruptedException success) {}
362 assertFalse(Thread.interrupted());
363 }});
364
365 await(pleaseInterrupt);
366 assertThreadStaysAlive(t);
367 t.interrupt();
368 awaitTermination(t);
369 }
370
371 /**
372 * poll succeeds unless empty
373 */
374 public void testPoll() {
375 DelayQueue q = populatedQueue(SIZE);
376 for (int i = 0; i < SIZE; ++i) {
377 assertEquals(new PDelay(i), q.poll());
378 }
379 assertNull(q.poll());
380 }
381
382 /**
383 * timed poll with zero timeout succeeds when non-empty, else times out
384 */
385 public void testTimedPoll0() throws InterruptedException {
386 DelayQueue q = populatedQueue(SIZE);
387 for (int i = 0; i < SIZE; ++i) {
388 assertEquals(new PDelay(i), q.poll(0, MILLISECONDS));
389 }
390 assertNull(q.poll(0, MILLISECONDS));
391 }
392
393 /**
394 * timed poll with nonzero timeout succeeds when non-empty, else times out
395 */
396 public void testTimedPoll() throws InterruptedException {
397 DelayQueue q = populatedQueue(SIZE);
398 for (int i = 0; i < SIZE; ++i) {
399 long startTime = System.nanoTime();
400 assertEquals(new PDelay(i), q.poll(LONG_DELAY_MS, MILLISECONDS));
401 assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
402 }
403 long startTime = System.nanoTime();
404 assertNull(q.poll(timeoutMillis(), MILLISECONDS));
405 assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
406 checkEmpty(q);
407 }
408
409 /**
410 * Interrupted timed poll throws InterruptedException instead of
411 * returning timeout status
412 */
413 public void testInterruptedTimedPoll() throws InterruptedException {
414 final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
415 final DelayQueue q = populatedQueue(SIZE);
416 Thread t = newStartedThread(new CheckedRunnable() {
417 public void realRun() throws InterruptedException {
418 long startTime = System.nanoTime();
419 for (int i = 0; i < SIZE; ++i) {
420 assertEquals(new PDelay(i),
421 ((PDelay)q.poll(LONG_DELAY_MS, MILLISECONDS)));
422 }
423
424 Thread.currentThread().interrupt();
425 try {
426 q.poll(LONG_DELAY_MS, MILLISECONDS);
427 shouldThrow();
428 } catch (InterruptedException success) {}
429 assertFalse(Thread.interrupted());
430
431 pleaseInterrupt.countDown();
432 try {
433 q.poll(LONG_DELAY_MS, MILLISECONDS);
434 shouldThrow();
435 } catch (InterruptedException success) {}
436 assertFalse(Thread.interrupted());
437 assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
438 }});
439
440 await(pleaseInterrupt);
441 assertThreadStaysAlive(t);
442 t.interrupt();
443 awaitTermination(t);
444 checkEmpty(q);
445 }
446
447 /**
448 * peek returns next element, or null if empty
449 */
450 public void testPeek() {
451 DelayQueue q = populatedQueue(SIZE);
452 for (int i = 0; i < SIZE; ++i) {
453 assertEquals(new PDelay(i), q.peek());
454 assertEquals(new PDelay(i), q.poll());
455 if (q.isEmpty())
456 assertNull(q.peek());
457 else
458 assertFalse(new PDelay(i).equals(q.peek()));
459 }
460 assertNull(q.peek());
461 }
462
463 /**
464 * element returns next element, or throws NSEE if empty
465 */
466 public void testElement() {
467 DelayQueue q = populatedQueue(SIZE);
468 for (int i = 0; i < SIZE; ++i) {
469 assertEquals(new PDelay(i), q.element());
470 q.poll();
471 }
472 try {
473 q.element();
474 shouldThrow();
475 } catch (NoSuchElementException success) {}
476 }
477
478 /**
479 * remove removes next element, or throws NSEE if empty
480 */
481 public void testRemove() {
482 DelayQueue q = populatedQueue(SIZE);
483 for (int i = 0; i < SIZE; ++i) {
484 assertEquals(new PDelay(i), q.remove());
485 }
486 try {
487 q.remove();
488 shouldThrow();
489 } catch (NoSuchElementException success) {}
490 }
491
492 /**
493 * contains(x) reports true when elements added but not yet removed
494 */
495 public void testContains() {
496 DelayQueue q = populatedQueue(SIZE);
497 for (int i = 0; i < SIZE; ++i) {
498 assertTrue(q.contains(new PDelay(i)));
499 q.poll();
500 assertFalse(q.contains(new PDelay(i)));
501 }
502 }
503
504 /**
505 * clear removes all elements
506 */
507 public void testClear() {
508 DelayQueue q = populatedQueue(SIZE);
509 q.clear();
510 assertTrue(q.isEmpty());
511 assertEquals(0, q.size());
512 assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
513 PDelay x = new PDelay(1);
514 q.add(x);
515 assertFalse(q.isEmpty());
516 assertTrue(q.contains(x));
517 q.clear();
518 assertTrue(q.isEmpty());
519 }
520
521 /**
522 * containsAll(c) is true when c contains a subset of elements
523 */
524 public void testContainsAll() {
525 DelayQueue q = populatedQueue(SIZE);
526 DelayQueue p = new DelayQueue();
527 for (int i = 0; i < SIZE; ++i) {
528 assertTrue(q.containsAll(p));
529 assertFalse(p.containsAll(q));
530 p.add(new PDelay(i));
531 }
532 assertTrue(p.containsAll(q));
533 }
534
535 /**
536 * retainAll(c) retains only those elements of c and reports true if changed
537 */
538 public void testRetainAll() {
539 DelayQueue q = populatedQueue(SIZE);
540 DelayQueue p = populatedQueue(SIZE);
541 for (int i = 0; i < SIZE; ++i) {
542 boolean changed = q.retainAll(p);
543 if (i == 0)
544 assertFalse(changed);
545 else
546 assertTrue(changed);
547
548 assertTrue(q.containsAll(p));
549 assertEquals(SIZE - i, q.size());
550 p.remove();
551 }
552 }
553
554 /**
555 * removeAll(c) removes only those elements of c and reports true if changed
556 */
557 public void testRemoveAll() {
558 for (int i = 1; i < SIZE; ++i) {
559 DelayQueue q = populatedQueue(SIZE);
560 DelayQueue p = populatedQueue(i);
561 assertTrue(q.removeAll(p));
562 assertEquals(SIZE - i, q.size());
563 for (int j = 0; j < i; ++j) {
564 PDelay x = (PDelay)(p.remove());
565 assertFalse(q.contains(x));
566 }
567 }
568 }
569
570 /**
571 * toArray contains all elements
572 */
573 public void testToArray() throws InterruptedException {
574 DelayQueue q = populatedQueue(SIZE);
575 Object[] o = q.toArray();
576 Arrays.sort(o);
577 for (int i = 0; i < o.length; i++)
578 assertSame(o[i], q.take());
579 }
580
581 /**
582 * toArray(a) contains all elements
583 */
584 public void testToArray2() {
585 DelayQueue<PDelay> q = populatedQueue(SIZE);
586 PDelay[] ints = new PDelay[SIZE];
587 PDelay[] array = q.toArray(ints);
588 assertSame(ints, array);
589 Arrays.sort(ints);
590 for (int i = 0; i < ints.length; i++)
591 assertSame(ints[i], q.remove());
592 }
593
594 /**
595 * toArray(incompatible array type) throws ArrayStoreException
596 */
597 public void testToArray1_BadArg() {
598 DelayQueue q = populatedQueue(SIZE);
599 try {
600 q.toArray(new String[10]);
601 shouldThrow();
602 } catch (ArrayStoreException success) {}
603 }
604
605 /**
606 * iterator iterates through all elements
607 */
608 public void testIterator() {
609 DelayQueue q = populatedQueue(SIZE);
610 int i = 0;
611 Iterator it = q.iterator();
612 while (it.hasNext()) {
613 assertTrue(q.contains(it.next()));
614 ++i;
615 }
616 assertEquals(i, SIZE);
617 assertIteratorExhausted(it);
618 }
619
620 /**
621 * iterator of empty collection has no elements
622 */
623 public void testEmptyIterator() {
624 assertIteratorExhausted(new DelayQueue().iterator());
625 }
626
627 /**
628 * iterator.remove removes current element
629 */
630 public void testIteratorRemove() {
631 final DelayQueue q = new DelayQueue();
632 q.add(new PDelay(2));
633 q.add(new PDelay(1));
634 q.add(new PDelay(3));
635 Iterator it = q.iterator();
636 it.next();
637 it.remove();
638 it = q.iterator();
639 assertEquals(new PDelay(2), it.next());
640 assertEquals(new PDelay(3), it.next());
641 assertFalse(it.hasNext());
642 }
643
644 /**
645 * toString contains toStrings of elements
646 */
647 public void testToString() {
648 DelayQueue q = populatedQueue(SIZE);
649 String s = q.toString();
650 for (Object e : q)
651 assertTrue(s.contains(e.toString()));
652 }
653
654 /**
655 * timed poll transfers elements across Executor tasks
656 */
657 public void testPollInExecutor() {
658 final DelayQueue q = new DelayQueue();
659 final CheckedBarrier threadsStarted = new CheckedBarrier(2);
660 final ExecutorService executor = Executors.newFixedThreadPool(2);
661 try (PoolCleaner cleaner = cleaner(executor)) {
662 executor.execute(new CheckedRunnable() {
663 public void realRun() throws InterruptedException {
664 assertNull(q.poll());
665 threadsStarted.await();
666 assertNotNull(q.poll(LONG_DELAY_MS, MILLISECONDS));
667 checkEmpty(q);
668 }});
669
670 executor.execute(new CheckedRunnable() {
671 public void realRun() throws InterruptedException {
672 threadsStarted.await();
673 q.put(new PDelay(1));
674 }});
675 }
676 }
677
678 /**
679 * Delayed actions do not occur until their delay elapses
680 */
681 public void testDelay() throws InterruptedException {
682 DelayQueue<NanoDelay> q = new DelayQueue<NanoDelay>();
683 for (int i = 0; i < SIZE; ++i)
684 q.add(new NanoDelay(1000000L * (SIZE - i)));
685
686 long last = 0;
687 for (int i = 0; i < SIZE; ++i) {
688 NanoDelay e = q.take();
689 long tt = e.getTriggerTime();
690 assertTrue(System.nanoTime() - tt >= 0);
691 if (i != 0)
692 assertTrue(tt >= last);
693 last = tt;
694 }
695 assertTrue(q.isEmpty());
696 }
697
698 /**
699 * peek of a non-empty queue returns non-null even if not expired
700 */
701 public void testPeekDelayed() {
702 DelayQueue q = new DelayQueue();
703 q.add(new NanoDelay(Long.MAX_VALUE));
704 assertNotNull(q.peek());
705 }
706
707 /**
708 * poll of a non-empty queue returns null if no expired elements.
709 */
710 public void testPollDelayed() {
711 DelayQueue q = new DelayQueue();
712 q.add(new NanoDelay(Long.MAX_VALUE));
713 assertNull(q.poll());
714 }
715
716 /**
717 * timed poll of a non-empty queue returns null if no expired elements.
718 */
719 public void testTimedPollDelayed() throws InterruptedException {
720 DelayQueue q = new DelayQueue();
721 q.add(new NanoDelay(LONG_DELAY_MS * 1000000L));
722 assertNull(q.poll(timeoutMillis(), MILLISECONDS));
723 }
724
725 /**
726 * drainTo(c) empties queue into another collection c
727 */
728 public void testDrainTo() {
729 DelayQueue q = new DelayQueue();
730 PDelay[] elems = new PDelay[SIZE];
731 for (int i = 0; i < SIZE; ++i) {
732 elems[i] = new PDelay(i);
733 q.add(elems[i]);
734 }
735 ArrayList l = new ArrayList();
736 q.drainTo(l);
737 assertEquals(0, q.size());
738 for (int i = 0; i < SIZE; ++i)
739 assertEquals(elems[i], l.get(i));
740 q.add(elems[0]);
741 q.add(elems[1]);
742 assertFalse(q.isEmpty());
743 assertTrue(q.contains(elems[0]));
744 assertTrue(q.contains(elems[1]));
745 l.clear();
746 q.drainTo(l);
747 assertEquals(0, q.size());
748 assertEquals(2, l.size());
749 for (int i = 0; i < 2; ++i)
750 assertEquals(elems[i], l.get(i));
751 }
752
753 /**
754 * drainTo empties queue
755 */
756 public void testDrainToWithActivePut() throws InterruptedException {
757 final DelayQueue q = populatedQueue(SIZE);
758 Thread t = new Thread(new CheckedRunnable() {
759 public void realRun() {
760 q.put(new PDelay(SIZE + 1));
761 }});
762
763 t.start();
764 ArrayList l = new ArrayList();
765 q.drainTo(l);
766 assertTrue(l.size() >= SIZE);
767 t.join();
768 assertTrue(q.size() + l.size() >= SIZE);
769 }
770
771 /**
772 * drainTo(c, n) empties first min(n, size) elements of queue into c
773 */
774 public void testDrainToN() {
775 for (int i = 0; i < SIZE + 2; ++i) {
776 DelayQueue q = populatedQueue(SIZE);
777 ArrayList l = new ArrayList();
778 q.drainTo(l, i);
779 int k = (i < SIZE) ? i : SIZE;
780 assertEquals(SIZE - k, q.size());
781 assertEquals(k, l.size());
782 }
783 }
784
785 /**
786 * remove(null), contains(null) always return false
787 */
788 public void testNeverContainsNull() {
789 Collection<?> q = populatedQueue(SIZE);
790 assertFalse(q.contains(null));
791 assertFalse(q.remove(null));
792 }
793 }