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.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 */
22
23 /*
24 * This file is available under and governed by the GNU General Public
25 * License version 2 only, as published by the Free Software Foundation.
26 * However, the following notice accompanied the original version of this
27 * file:
28 *
29 * Written by Doug Lea and Martin Buchholz with assistance from
30 * members of JCP JSR-166 Expert Group and released to the public
31 * domain, as explained at
32 * http://creativecommons.org/publicdomain/zero/1.0/
33 */
34
35 import static java.util.concurrent.TimeUnit.HOURS;
36 import static java.util.concurrent.TimeUnit.MILLISECONDS;
37
38 import java.util.ArrayDeque;
39 import java.util.ArrayList;
40 import java.util.Arrays;
41 import java.util.Collection;
42 import java.util.Collections;
43 import java.util.ConcurrentModificationException;
44 import java.util.Deque;
45 import java.util.HashSet;
46 import java.util.Iterator;
47 import java.util.List;
48 import java.util.NoSuchElementException;
49 import java.util.Queue;
50 import java.util.Set;
51 import java.util.Spliterator;
52 import java.util.concurrent.BlockingDeque;
53 import java.util.concurrent.BlockingQueue;
54 import java.util.concurrent.ConcurrentLinkedQueue;
55 import java.util.concurrent.CountDownLatch;
56 import java.util.concurrent.Executors;
57 import java.util.concurrent.ExecutorService;
58 import java.util.concurrent.Future;
59 import java.util.concurrent.Phaser;
60 import java.util.concurrent.ThreadLocalRandom;
61 import java.util.concurrent.atomic.AtomicBoolean;
62 import java.util.concurrent.atomic.AtomicLong;
63 import java.util.concurrent.atomic.AtomicReference;
64 import java.util.function.Consumer;
65 import java.util.function.Predicate;
66 import java.util.stream.Collectors;
67
68 import junit.framework.Test;
69
70 /**
71 * Contains tests applicable to all jdk8+ Collection implementations.
72 * An extension of CollectionTest.
73 */
74 public class Collection8Test extends JSR166TestCase {
75 final CollectionImplementation impl;
76
77 /** Tests are parameterized by a Collection implementation. */
78 Collection8Test(CollectionImplementation impl, String methodName) {
79 super(methodName);
80 this.impl = impl;
81 }
82
83 public static Test testSuite(CollectionImplementation impl) {
84 return parameterizedTestSuite(Collection8Test.class,
85 CollectionImplementation.class,
86 impl);
87 }
88
89 Object bomb() {
90 return new Object() {
91 @Override public boolean equals(Object x) { throw new AssertionError(); }
92 @Override public int hashCode() { throw new AssertionError(); }
93 @Override public String toString() { throw new AssertionError(); }
94 };
95 }
96
97 /** Checks properties of empty collections. */
98 public void testEmptyMeansEmpty() throws Throwable {
99 Collection c = impl.emptyCollection();
100 emptyMeansEmpty(c);
101
102 if (c instanceof java.io.Serializable) {
103 try {
104 emptyMeansEmpty(serialClonePossiblyFailing(c));
105 } catch (java.io.NotSerializableException ex) {
106 // excusable when we have a serializable wrapper around
107 // a non-serializable collection, as can happen with:
108 // Vector.subList() => wrapped AbstractList$RandomAccessSubList
109 if (testImplementationDetails
110 && (! c.getClass().getName().matches(
111 "java.util.Collections.*")))
112 throw ex;
113 }
114 }
115
116 Collection clone = cloneableClone(c);
117 if (clone != null)
118 emptyMeansEmpty(clone);
119 }
120
121 void emptyMeansEmpty(Collection c) throws InterruptedException {
122 assertTrue(c.isEmpty());
123 assertEquals(0, c.size());
124 assertEquals("[]", c.toString());
125 if (c instanceof List<?>) {
126 List x = (List) c;
127 assertEquals(1, x.hashCode());
128 assertEquals(x, Collections.emptyList());
129 assertEquals(Collections.emptyList(), x);
130 assertEquals(-1, x.indexOf(impl.makeElement(86)));
131 assertEquals(-1, x.lastIndexOf(impl.makeElement(99)));
132 assertThrows(
133 IndexOutOfBoundsException.class,
134 () -> x.get(0),
135 () -> x.set(0, impl.makeElement(42)));
136 }
137 else if (c instanceof Set<?>) {
138 assertEquals(0, c.hashCode());
139 assertEquals(c, Collections.emptySet());
140 assertEquals(Collections.emptySet(), c);
141 }
142 {
143 Object[] a = c.toArray();
144 assertEquals(0, a.length);
145 assertSame(Object[].class, a.getClass());
146 }
147 {
148 Object[] a = new Object[0];
149 assertSame(a, c.toArray(a));
150 }
151 {
152 Integer[] a = new Integer[0];
153 assertSame(a, c.toArray(a));
154 }
155 {
156 Integer[] a = { 1, 2, 3};
157 assertSame(a, c.toArray(a));
158 assertNull(a[0]);
159 assertSame(2, a[1]);
160 assertSame(3, a[2]);
161 }
162 assertIteratorExhausted(c.iterator());
163 Consumer alwaysThrows = e -> { throw new AssertionError(); };
164 c.forEach(alwaysThrows);
165 c.iterator().forEachRemaining(alwaysThrows);
166 c.spliterator().forEachRemaining(alwaysThrows);
167 assertFalse(c.spliterator().tryAdvance(alwaysThrows));
168 if (c.spliterator().hasCharacteristics(Spliterator.SIZED))
169 assertEquals(0, c.spliterator().estimateSize());
170 assertFalse(c.contains(bomb()));
171 assertFalse(c.remove(bomb()));
172 if (c instanceof Queue) {
173 Queue q = (Queue) c;
174 assertNull(q.peek());
175 assertNull(q.poll());
176 }
177 if (c instanceof Deque) {
178 Deque d = (Deque) c;
179 assertNull(d.peekFirst());
180 assertNull(d.peekLast());
181 assertNull(d.pollFirst());
182 assertNull(d.pollLast());
183 assertIteratorExhausted(d.descendingIterator());
184 d.descendingIterator().forEachRemaining(alwaysThrows);
185 assertFalse(d.removeFirstOccurrence(bomb()));
186 assertFalse(d.removeLastOccurrence(bomb()));
187 }
188 if (c instanceof BlockingQueue) {
189 BlockingQueue q = (BlockingQueue) c;
190 assertNull(q.poll(randomExpiredTimeout(), randomTimeUnit()));
191 }
192 if (c instanceof BlockingDeque) {
193 BlockingDeque q = (BlockingDeque) c;
194 assertNull(q.pollFirst(randomExpiredTimeout(), randomTimeUnit()));
195 assertNull(q.pollLast(randomExpiredTimeout(), randomTimeUnit()));
196 }
197 }
198
199 public void testNullPointerExceptions() throws InterruptedException {
200 Collection c = impl.emptyCollection();
201 assertThrows(
202 NullPointerException.class,
203 () -> c.addAll(null),
204 () -> c.containsAll(null),
205 () -> c.retainAll(null),
206 () -> c.removeAll(null),
207 () -> c.removeIf(null),
208 () -> c.forEach(null),
209 () -> c.iterator().forEachRemaining(null),
210 () -> c.spliterator().forEachRemaining(null),
211 () -> c.spliterator().tryAdvance(null),
212 () -> c.toArray((Object[])null));
213
214 if (!impl.permitsNulls()) {
215 assertThrows(
216 NullPointerException.class,
217 () -> c.add(null));
218 }
219 if (!impl.permitsNulls() && c instanceof Queue) {
220 Queue q = (Queue) c;
221 assertThrows(
222 NullPointerException.class,
223 () -> q.offer(null));
224 }
225 if (!impl.permitsNulls() && c instanceof Deque) {
226 Deque d = (Deque) c;
227 assertThrows(
228 NullPointerException.class,
229 () -> d.addFirst(null),
230 () -> d.addLast(null),
231 () -> d.offerFirst(null),
232 () -> d.offerLast(null),
233 () -> d.push(null),
234 () -> d.descendingIterator().forEachRemaining(null));
235 }
236 if (c instanceof BlockingQueue) {
237 BlockingQueue q = (BlockingQueue) c;
238 assertThrows(
239 NullPointerException.class,
240 () -> {
241 try { q.offer(null, 1L, HOURS); }
242 catch (InterruptedException ex) {
243 throw new AssertionError(ex);
244 }},
245 () -> {
246 try { q.put(null); }
247 catch (InterruptedException ex) {
248 throw new AssertionError(ex);
249 }});
250 }
251 if (c instanceof BlockingDeque) {
252 BlockingDeque q = (BlockingDeque) c;
253 assertThrows(
254 NullPointerException.class,
255 () -> {
256 try { q.offerFirst(null, 1L, HOURS); }
257 catch (InterruptedException ex) {
258 throw new AssertionError(ex);
259 }},
260 () -> {
261 try { q.offerLast(null, 1L, HOURS); }
262 catch (InterruptedException ex) {
263 throw new AssertionError(ex);
264 }},
265 () -> {
266 try { q.putFirst(null); }
267 catch (InterruptedException ex) {
268 throw new AssertionError(ex);
269 }},
270 () -> {
271 try { q.putLast(null); }
272 catch (InterruptedException ex) {
273 throw new AssertionError(ex);
274 }});
275 }
276 }
277
278 public void testNoSuchElementExceptions() {
279 Collection c = impl.emptyCollection();
280 assertThrows(
281 NoSuchElementException.class,
282 () -> c.iterator().next());
283
284 if (c instanceof Queue) {
285 Queue q = (Queue) c;
286 assertThrows(
287 NoSuchElementException.class,
288 () -> q.element(),
289 () -> q.remove());
290 }
291 if (c instanceof Deque) {
292 Deque d = (Deque) c;
293 assertThrows(
294 NoSuchElementException.class,
295 () -> d.getFirst(),
296 () -> d.getLast(),
297 () -> d.removeFirst(),
298 () -> d.removeLast(),
299 () -> d.pop(),
300 () -> d.descendingIterator().next());
301 }
302 if (c instanceof List) {
303 List x = (List) c;
304 assertThrows(
305 NoSuchElementException.class,
306 () -> x.iterator().next(),
307 () -> x.listIterator().next(),
308 () -> x.listIterator(0).next(),
309 () -> x.listIterator().previous(),
310 () -> x.listIterator(0).previous());
311 }
312 }
313
314 public void testRemoveIf() {
315 Collection c = impl.emptyCollection();
316 boolean ordered =
317 c.spliterator().hasCharacteristics(Spliterator.ORDERED);
318 ThreadLocalRandom rnd = ThreadLocalRandom.current();
319 int n = rnd.nextInt(6);
320 for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
321 AtomicReference threwAt = new AtomicReference(null);
322 List orig = rnd.nextBoolean()
323 ? new ArrayList(c)
324 : Arrays.asList(c.toArray());
325
326 // Merely creating an iterator can change ArrayBlockingQueue behavior
327 Iterator it = rnd.nextBoolean() ? c.iterator() : null;
328
329 ArrayList survivors = new ArrayList();
330 ArrayList accepts = new ArrayList();
331 ArrayList rejects = new ArrayList();
332
333 Predicate randomPredicate = e -> {
334 assertNull(threwAt.get());
335 switch (rnd.nextInt(3)) {
336 case 0: accepts.add(e); return true;
337 case 1: rejects.add(e); return false;
338 case 2: threwAt.set(e); throw new ArithmeticException();
339 default: throw new AssertionError();
340 }
341 };
342 try {
343 try {
344 boolean modified = c.removeIf(randomPredicate);
345 assertNull(threwAt.get());
346 assertEquals(modified, accepts.size() > 0);
347 assertEquals(modified, rejects.size() != n);
348 assertEquals(accepts.size() + rejects.size(), n);
349 if (ordered) {
350 assertEquals(rejects,
351 Arrays.asList(c.toArray()));
352 } else {
353 assertEquals(new HashSet(rejects),
354 new HashSet(Arrays.asList(c.toArray())));
355 }
356 } catch (ArithmeticException ok) {
357 assertNotNull(threwAt.get());
358 assertTrue(c.contains(threwAt.get()));
359 }
360 if (it != null && impl.isConcurrent())
361 // check for weakly consistent iterator
362 while (it.hasNext()) assertTrue(orig.contains(it.next()));
363 switch (rnd.nextInt(4)) {
364 case 0: survivors.addAll(c); break;
365 case 1: survivors.addAll(Arrays.asList(c.toArray())); break;
366 case 2: c.forEach(survivors::add); break;
367 case 3: for (Object e : c) survivors.add(e); break;
368 }
369 assertTrue(orig.containsAll(accepts));
370 assertTrue(orig.containsAll(rejects));
371 assertTrue(orig.containsAll(survivors));
372 assertTrue(orig.containsAll(c));
373 assertTrue(c.containsAll(rejects));
374 assertTrue(c.containsAll(survivors));
375 assertTrue(survivors.containsAll(rejects));
376 if (threwAt.get() == null) {
377 assertEquals(n - accepts.size(), c.size());
378 for (Object x : accepts) assertFalse(c.contains(x));
379 } else {
380 // Two acceptable behaviors: entire removeIf call is one
381 // transaction, or each element processed is one transaction.
382 assertTrue(n == c.size() || n == c.size() + accepts.size());
383 int k = 0;
384 for (Object x : accepts) if (c.contains(x)) k++;
385 assertTrue(k == accepts.size() || k == 0);
386 }
387 } catch (Throwable ex) {
388 System.err.println(impl.klazz());
389 // c is at risk of corruption if we got here, so be lenient
390 try { System.err.printf("c=%s%n", c); }
391 catch (Throwable t) { t.printStackTrace(); }
392 System.err.printf("n=%d%n", n);
393 System.err.printf("orig=%s%n", orig);
394 System.err.printf("accepts=%s%n", accepts);
395 System.err.printf("rejects=%s%n", rejects);
396 System.err.printf("survivors=%s%n", survivors);
397 System.err.printf("threwAt=%s%n", threwAt.get());
398 throw ex;
399 }
400 }
401
402 /**
403 * All elements removed in the middle of CONCURRENT traversal.
404 */
405 public void testElementRemovalDuringTraversal() {
406 Collection c = impl.emptyCollection();
407 ThreadLocalRandom rnd = ThreadLocalRandom.current();
408 int n = rnd.nextInt(6);
409 ArrayList copy = new ArrayList();
410 for (int i = 0; i < n; i++) {
411 Object x = impl.makeElement(i);
412 copy.add(x);
413 c.add(x);
414 }
415 ArrayList iterated = new ArrayList();
416 ArrayList spliterated = new ArrayList();
417 Spliterator s = c.spliterator();
418 Iterator it = c.iterator();
419 for (int i = rnd.nextInt(n + 1); --i >= 0; ) {
420 assertTrue(s.tryAdvance(spliterated::add));
421 if (rnd.nextBoolean()) assertTrue(it.hasNext());
422 iterated.add(it.next());
423 }
424 Consumer alwaysThrows = e -> { throw new AssertionError(); };
425 if (s.hasCharacteristics(Spliterator.CONCURRENT)) {
426 c.clear(); // TODO: many more removal methods
427 if (testImplementationDetails
428 && !(c instanceof java.util.concurrent.ArrayBlockingQueue)) {
429 if (rnd.nextBoolean())
430 assertFalse(s.tryAdvance(alwaysThrows));
431 else
432 s.forEachRemaining(alwaysThrows);
433 }
434 if (it.hasNext()) iterated.add(it.next());
435 if (rnd.nextBoolean()) assertIteratorExhausted(it);
436 }
437 assertTrue(copy.containsAll(iterated));
438 assertTrue(copy.containsAll(spliterated));
439 }
440
441 /**
442 * Some elements randomly disappear in the middle of traversal.
443 */
444 public void testRandomElementRemovalDuringTraversal() {
445 Collection c = impl.emptyCollection();
446 ThreadLocalRandom rnd = ThreadLocalRandom.current();
447 int n = rnd.nextInt(6);
448 ArrayList copy = new ArrayList();
449 for (int i = 0; i < n; i++) {
450 Object x = impl.makeElement(i);
451 copy.add(x);
452 c.add(x);
453 }
454 ArrayList iterated = new ArrayList();
455 ArrayList spliterated = new ArrayList();
456 ArrayList removed = new ArrayList();
457 Spliterator s = c.spliterator();
458 Iterator it = c.iterator();
459 if (! (s.hasCharacteristics(Spliterator.CONCURRENT) ||
460 s.hasCharacteristics(Spliterator.IMMUTABLE)))
461 return;
462 for (int i = rnd.nextInt(n + 1); --i >= 0; ) {
463 assertTrue(s.tryAdvance(e -> {}));
464 if (rnd.nextBoolean()) assertTrue(it.hasNext());
465 it.next();
466 }
467 Consumer alwaysThrows = e -> { throw new AssertionError(); };
468 // TODO: many more removal methods
469 if (rnd.nextBoolean()) {
470 for (Iterator z = c.iterator(); z.hasNext(); ) {
471 Object e = z.next();
472 if (rnd.nextBoolean()) {
473 try {
474 z.remove();
475 } catch (UnsupportedOperationException ok) { return; }
476 removed.add(e);
477 }
478 }
479 } else {
480 Predicate randomlyRemove = e -> {
481 if (rnd.nextBoolean()) { removed.add(e); return true; }
482 else return false;
483 };
484 c.removeIf(randomlyRemove);
485 }
486 s.forEachRemaining(spliterated::add);
487 while (it.hasNext())
488 iterated.add(it.next());
489 assertTrue(copy.containsAll(iterated));
490 assertTrue(copy.containsAll(spliterated));
491 assertTrue(copy.containsAll(removed));
492 if (s.hasCharacteristics(Spliterator.CONCURRENT)) {
493 ArrayList iteratedAndRemoved = new ArrayList(iterated);
494 ArrayList spliteratedAndRemoved = new ArrayList(spliterated);
495 iteratedAndRemoved.retainAll(removed);
496 spliteratedAndRemoved.retainAll(removed);
497 assertTrue(iteratedAndRemoved.size() <= 1);
498 assertTrue(spliteratedAndRemoved.size() <= 1);
499 if (testImplementationDetails
500 && !(c instanceof java.util.concurrent.ArrayBlockingQueue))
501 assertTrue(spliteratedAndRemoved.isEmpty());
502 }
503 }
504
505 /**
506 * Various ways of traversing a collection yield same elements
507 */
508 public void testTraversalEquivalence() {
509 Collection c = impl.emptyCollection();
510 ThreadLocalRandom rnd = ThreadLocalRandom.current();
511 int n = rnd.nextInt(6);
512 for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
513 ArrayList iterated = new ArrayList();
514 ArrayList iteratedForEachRemaining = new ArrayList();
515 ArrayList tryAdvanced = new ArrayList();
516 ArrayList spliterated = new ArrayList();
517 ArrayList splitonced = new ArrayList();
518 ArrayList forEached = new ArrayList();
519 ArrayList streamForEached = new ArrayList();
520 ConcurrentLinkedQueue parallelStreamForEached = new ConcurrentLinkedQueue();
521 ArrayList removeIfed = new ArrayList();
522 for (Object x : c) iterated.add(x);
523 c.iterator().forEachRemaining(iteratedForEachRemaining::add);
524 for (Spliterator s = c.spliterator();
525 s.tryAdvance(tryAdvanced::add); ) {}
526 c.spliterator().forEachRemaining(spliterated::add);
527 { // trySplit returns "strict prefix"
528 Spliterator s1 = c.spliterator(), s2 = s1.trySplit();
529 if (s2 != null) s2.forEachRemaining(splitonced::add);
530 s1.forEachRemaining(splitonced::add);
531 }
532 c.forEach(forEached::add);
533 c.stream().forEach(streamForEached::add);
534 c.parallelStream().forEach(parallelStreamForEached::add);
535 c.removeIf(e -> { removeIfed.add(e); return false; });
536 boolean ordered =
537 c.spliterator().hasCharacteristics(Spliterator.ORDERED);
538 if (c instanceof List || c instanceof Deque)
539 assertTrue(ordered);
540 HashSet cset = new HashSet(c);
541 assertEquals(cset, new HashSet(parallelStreamForEached));
542 if (ordered) {
543 assertEquals(iterated, iteratedForEachRemaining);
544 assertEquals(iterated, tryAdvanced);
545 assertEquals(iterated, spliterated);
546 assertEquals(iterated, splitonced);
547 assertEquals(iterated, forEached);
548 assertEquals(iterated, streamForEached);
549 assertEquals(iterated, removeIfed);
550 } else {
551 assertEquals(cset, new HashSet(iterated));
552 assertEquals(cset, new HashSet(iteratedForEachRemaining));
553 assertEquals(cset, new HashSet(tryAdvanced));
554 assertEquals(cset, new HashSet(spliterated));
555 assertEquals(cset, new HashSet(splitonced));
556 assertEquals(cset, new HashSet(forEached));
557 assertEquals(cset, new HashSet(streamForEached));
558 assertEquals(cset, new HashSet(removeIfed));
559 }
560 if (c instanceof Deque) {
561 Deque d = (Deque) c;
562 ArrayList descending = new ArrayList();
563 ArrayList descendingForEachRemaining = new ArrayList();
564 for (Iterator it = d.descendingIterator(); it.hasNext(); )
565 descending.add(it.next());
566 d.descendingIterator().forEachRemaining(
567 e -> descendingForEachRemaining.add(e));
568 Collections.reverse(descending);
569 Collections.reverse(descendingForEachRemaining);
570 assertEquals(iterated, descending);
571 assertEquals(iterated, descendingForEachRemaining);
572 }
573 }
574
575 /**
576 * Iterator.forEachRemaining has same behavior as Iterator's
577 * default implementation.
578 */
579 public void testForEachRemainingConsistentWithDefaultImplementation() {
580 Collection c = impl.emptyCollection();
581 if (!testImplementationDetails
582 || c.getClass() == java.util.LinkedList.class)
583 return;
584 ThreadLocalRandom rnd = ThreadLocalRandom.current();
585 int n = 1 + rnd.nextInt(3);
586 for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
587 ArrayList iterated = new ArrayList();
588 ArrayList iteratedForEachRemaining = new ArrayList();
589 Iterator it1 = c.iterator();
590 Iterator it2 = c.iterator();
591 assertTrue(it1.hasNext());
592 assertTrue(it2.hasNext());
593 c.clear();
594 Object r1, r2;
595 try {
596 while (it1.hasNext()) iterated.add(it1.next());
597 r1 = iterated;
598 } catch (ConcurrentModificationException ex) {
599 r1 = ConcurrentModificationException.class;
600 assertFalse(impl.isConcurrent());
601 }
602 try {
603 it2.forEachRemaining(iteratedForEachRemaining::add);
604 r2 = iteratedForEachRemaining;
605 } catch (ConcurrentModificationException ex) {
606 r2 = ConcurrentModificationException.class;
607 assertFalse(impl.isConcurrent());
608 }
609 assertEquals(r1, r2);
610 }
611
612 /**
613 * Calling Iterator#remove() after Iterator#forEachRemaining
614 * should (maybe) remove last element
615 */
616 public void testRemoveAfterForEachRemaining() {
617 Collection c = impl.emptyCollection();
618 ThreadLocalRandom rnd = ThreadLocalRandom.current();
619 ArrayList copy = new ArrayList();
620 boolean ordered = c.spliterator().hasCharacteristics(Spliterator.ORDERED);
621 testCollection: {
622 int n = 3 + rnd.nextInt(2);
623 for (int i = 0; i < n; i++) {
624 Object x = impl.makeElement(i);
625 c.add(x);
626 copy.add(x);
627 }
628 Iterator it = c.iterator();
629 if (ordered) {
630 if (rnd.nextBoolean()) assertTrue(it.hasNext());
631 assertEquals(impl.makeElement(0), it.next());
632 if (rnd.nextBoolean()) assertTrue(it.hasNext());
633 assertEquals(impl.makeElement(1), it.next());
634 } else {
635 if (rnd.nextBoolean()) assertTrue(it.hasNext());
636 assertTrue(copy.contains(it.next()));
637 if (rnd.nextBoolean()) assertTrue(it.hasNext());
638 assertTrue(copy.contains(it.next()));
639 }
640 if (rnd.nextBoolean()) assertTrue(it.hasNext());
641 it.forEachRemaining(
642 e -> {
643 assertTrue(c.contains(e));
644 assertTrue(copy.contains(e));});
645 if (testImplementationDetails) {
646 if (c instanceof java.util.concurrent.ArrayBlockingQueue) {
647 assertIteratorExhausted(it);
648 } else {
649 try { it.remove(); }
650 catch (UnsupportedOperationException ok) {
651 break testCollection;
652 }
653 assertEquals(n - 1, c.size());
654 if (ordered) {
655 for (int i = 0; i < n - 1; i++)
656 assertTrue(c.contains(impl.makeElement(i)));
657 assertFalse(c.contains(impl.makeElement(n - 1)));
658 }
659 }
660 }
661 }
662 if (c instanceof Deque) {
663 Deque d = (Deque) impl.emptyCollection();
664 assertTrue(ordered);
665 int n = 3 + rnd.nextInt(2);
666 for (int i = 0; i < n; i++) d.add(impl.makeElement(i));
667 Iterator it = d.descendingIterator();
668 assertTrue(it.hasNext());
669 assertEquals(impl.makeElement(n - 1), it.next());
670 assertTrue(it.hasNext());
671 assertEquals(impl.makeElement(n - 2), it.next());
672 it.forEachRemaining(e -> assertTrue(c.contains(e)));
673 if (testImplementationDetails) {
674 it.remove();
675 assertEquals(n - 1, d.size());
676 for (int i = 1; i < n; i++)
677 assertTrue(d.contains(impl.makeElement(i)));
678 assertFalse(d.contains(impl.makeElement(0)));
679 }
680 }
681 }
682
683 /**
684 * stream().forEach returns elements in the collection
685 */
686 public void testStreamForEach() throws Throwable {
687 final Collection c = impl.emptyCollection();
688 final AtomicLong count = new AtomicLong(0L);
689 final Object x = impl.makeElement(1);
690 final Object y = impl.makeElement(2);
691 final ArrayList found = new ArrayList();
692 Consumer<Object> spy = o -> found.add(o);
693 c.stream().forEach(spy);
694 assertTrue(found.isEmpty());
695
696 assertTrue(c.add(x));
697 c.stream().forEach(spy);
698 assertEquals(Collections.singletonList(x), found);
699 found.clear();
700
701 assertTrue(c.add(y));
702 c.stream().forEach(spy);
703 assertEquals(2, found.size());
704 assertTrue(found.contains(x));
705 assertTrue(found.contains(y));
706 found.clear();
707
708 c.clear();
709 c.stream().forEach(spy);
710 assertTrue(found.isEmpty());
711 }
712
713 public void testStreamForEachConcurrentStressTest() throws Throwable {
714 if (!impl.isConcurrent()) return;
715 final Collection c = impl.emptyCollection();
716 final long testDurationMillis = timeoutMillis();
717 final AtomicBoolean done = new AtomicBoolean(false);
718 final Object elt = impl.makeElement(1);
719 final Future<?> f1, f2;
720 final ExecutorService pool = Executors.newCachedThreadPool();
721 try (PoolCleaner cleaner = cleaner(pool, done)) {
722 final CountDownLatch threadsStarted = new CountDownLatch(2);
723 Runnable checkElt = () -> {
724 threadsStarted.countDown();
725 while (!done.get())
726 c.stream().forEach(x -> assertSame(x, elt)); };
727 Runnable addRemove = () -> {
728 threadsStarted.countDown();
729 while (!done.get()) {
730 assertTrue(c.add(elt));
731 assertTrue(c.remove(elt));
732 }};
733 f1 = pool.submit(checkElt);
734 f2 = pool.submit(addRemove);
735 Thread.sleep(testDurationMillis);
736 }
737 assertNull(f1.get(0L, MILLISECONDS));
738 assertNull(f2.get(0L, MILLISECONDS));
739 }
740
741 /**
742 * collection.forEach returns elements in the collection
743 */
744 public void testForEach() throws Throwable {
745 final Collection c = impl.emptyCollection();
746 final AtomicLong count = new AtomicLong(0L);
747 final Object x = impl.makeElement(1);
748 final Object y = impl.makeElement(2);
749 final ArrayList found = new ArrayList();
750 Consumer<Object> spy = o -> found.add(o);
751 c.forEach(spy);
752 assertTrue(found.isEmpty());
753
754 assertTrue(c.add(x));
755 c.forEach(spy);
756 assertEquals(Collections.singletonList(x), found);
757 found.clear();
758
759 assertTrue(c.add(y));
760 c.forEach(spy);
761 assertEquals(2, found.size());
762 assertTrue(found.contains(x));
763 assertTrue(found.contains(y));
764 found.clear();
765
766 c.clear();
767 c.forEach(spy);
768 assertTrue(found.isEmpty());
769 }
770
771 /** TODO: promote to a common utility */
772 static <T> T chooseOne(T ... ts) {
773 return ts[ThreadLocalRandom.current().nextInt(ts.length)];
774 }
775
776 /** TODO: more random adders and removers */
777 static <E> Runnable adderRemover(Collection<E> c, E e) {
778 return chooseOne(
779 () -> {
780 assertTrue(c.add(e));
781 assertTrue(c.contains(e));
782 assertTrue(c.remove(e));
783 assertFalse(c.contains(e));
784 },
785 () -> {
786 assertTrue(c.add(e));
787 assertTrue(c.contains(e));
788 assertTrue(c.removeIf(x -> x == e));
789 assertFalse(c.contains(e));
790 },
791 () -> {
792 assertTrue(c.add(e));
793 assertTrue(c.contains(e));
794 for (Iterator it = c.iterator();; )
795 if (it.next() == e) {
796 try { it.remove(); }
797 catch (UnsupportedOperationException ok) {
798 c.remove(e);
799 }
800 break;
801 }
802 assertFalse(c.contains(e));
803 });
804 }
805
806 /**
807 * Concurrent Spliterators, once exhausted, stay exhausted.
808 */
809 public void testStickySpliteratorExhaustion() throws Throwable {
810 if (!impl.isConcurrent()) return;
811 if (!testImplementationDetails) return;
812 final ThreadLocalRandom rnd = ThreadLocalRandom.current();
813 final Consumer alwaysThrows = e -> { throw new AssertionError(); };
814 final Collection c = impl.emptyCollection();
815 final Spliterator s = c.spliterator();
816 if (rnd.nextBoolean()) {
817 assertFalse(s.tryAdvance(alwaysThrows));
818 } else {
819 s.forEachRemaining(alwaysThrows);
820 }
821 final Object one = impl.makeElement(1);
822 // Spliterator should not notice added element
823 c.add(one);
824 if (rnd.nextBoolean()) {
825 assertFalse(s.tryAdvance(alwaysThrows));
826 } else {
827 s.forEachRemaining(alwaysThrows);
828 }
829 }
830
831 /**
832 * Motley crew of threads concurrently randomly hammer the collection.
833 */
834 public void testDetectRaces() throws Throwable {
835 if (!impl.isConcurrent()) return;
836 final ThreadLocalRandom rnd = ThreadLocalRandom.current();
837 final Collection c = impl.emptyCollection();
838 final long testDurationMillis
839 = expensiveTests ? LONG_DELAY_MS : timeoutMillis();
840 final AtomicBoolean done = new AtomicBoolean(false);
841 final Object one = impl.makeElement(1);
842 final Object two = impl.makeElement(2);
843 final Consumer checkSanity = x -> assertTrue(x == one || x == two);
844 final Consumer<Object[]> checkArraySanity = array -> {
845 // assertTrue(array.length <= 2); // duplicates are permitted
846 for (Object x : array) assertTrue(x == one || x == two);
847 };
848 final Object[] emptyArray =
849 (Object[]) java.lang.reflect.Array.newInstance(one.getClass(), 0);
850 final List<Future<?>> futures;
851 final Phaser threadsStarted = new Phaser(1); // register this thread
852 final Runnable[] frobbers = {
853 () -> c.forEach(checkSanity),
854 () -> c.stream().forEach(checkSanity),
855 () -> c.parallelStream().forEach(checkSanity),
856 () -> c.spliterator().trySplit(),
857 () -> {
858 Spliterator s = c.spliterator();
859 s.tryAdvance(checkSanity);
860 s.trySplit();
861 },
862 () -> {
863 Spliterator s = c.spliterator();
864 do {} while (s.tryAdvance(checkSanity));
865 },
866 () -> { for (Object x : c) checkSanity.accept(x); },
867 () -> checkArraySanity.accept(c.toArray()),
868 () -> checkArraySanity.accept(c.toArray(emptyArray)),
869 () -> {
870 Object[] a = new Object[5];
871 Object three = impl.makeElement(3);
872 Arrays.fill(a, 0, a.length, three);
873 Object[] x = c.toArray(a);
874 if (x == a)
875 for (int i = 0; i < a.length && a[i] != null; i++)
876 checkSanity.accept(a[i]);
877 // A careful reading of the spec does not support:
878 // for (i++; i < a.length; i++) assertSame(three, a[i]);
879 else
880 checkArraySanity.accept(x);
881 },
882 adderRemover(c, one),
883 adderRemover(c, two),
884 };
885 final List<Runnable> tasks =
886 Arrays.stream(frobbers)
887 .filter(task -> rnd.nextBoolean()) // random subset
888 .map(task -> (Runnable) () -> {
889 threadsStarted.arriveAndAwaitAdvance();
890 while (!done.get())
891 task.run();
892 })
893 .collect(Collectors.toList());
894 final ExecutorService pool = Executors.newCachedThreadPool();
895 try (PoolCleaner cleaner = cleaner(pool, done)) {
896 threadsStarted.bulkRegister(tasks.size());
897 futures = tasks.stream()
898 .map(pool::submit)
899 .collect(Collectors.toList());
900 threadsStarted.arriveAndDeregister();
901 Thread.sleep(testDurationMillis);
902 }
903 for (Future future : futures)
904 assertNull(future.get(0L, MILLISECONDS));
905 }
906
907 /**
908 * Spliterators are either IMMUTABLE or truly late-binding or, if
909 * concurrent, use the same "late-binding style" of returning
910 * elements added between creation and first use.
911 */
912 public void testLateBindingStyle() {
913 if (!testImplementationDetails) return;
914 if (impl.klazz() == ArrayList.class) return; // for jdk8
915 // Immutable (snapshot) spliterators are exempt
916 if (impl.emptyCollection().spliterator()
917 .hasCharacteristics(Spliterator.IMMUTABLE))
918 return;
919 final Object one = impl.makeElement(1);
920 {
921 final Collection c = impl.emptyCollection();
922 final Spliterator split = c.spliterator();
923 c.add(one);
924 assertTrue(split.tryAdvance(e -> { assertSame(e, one); }));
925 assertFalse(split.tryAdvance(e -> { throw new AssertionError(); }));
926 assertTrue(c.contains(one));
927 }
928 {
929 final AtomicLong count = new AtomicLong(0);
930 final Collection c = impl.emptyCollection();
931 final Spliterator split = c.spliterator();
932 c.add(one);
933 split.forEachRemaining(
934 e -> { assertSame(e, one); count.getAndIncrement(); });
935 assertEquals(1L, count.get());
936 assertFalse(split.tryAdvance(e -> { throw new AssertionError(); }));
937 assertTrue(c.contains(one));
938 }
939 }
940
941 /**
942 * Spliterator.getComparator throws IllegalStateException iff the
943 * spliterator does not report SORTED.
944 */
945 public void testGetComparator_IllegalStateException() {
946 Collection c = impl.emptyCollection();
947 Spliterator s = c.spliterator();
948 boolean reportsSorted = s.hasCharacteristics(Spliterator.SORTED);
949 try {
950 s.getComparator();
951 assertTrue(reportsSorted);
952 } catch (IllegalStateException ex) {
953 assertFalse(reportsSorted);
954 }
955 }
956
957 public void testCollectionCopies() throws Exception {
958 ThreadLocalRandom rnd = ThreadLocalRandom.current();
959 Collection c = impl.emptyCollection();
960 for (int n = rnd.nextInt(4); n--> 0; )
961 c.add(impl.makeElement(rnd.nextInt()));
962 assertEquals(c, c);
963 if (c instanceof List)
964 assertCollectionsEquals(c, new ArrayList(c));
965 else if (c instanceof Set)
966 assertCollectionsEquals(c, new HashSet(c));
967 else if (c instanceof Deque)
968 assertCollectionsEquivalent(c, new ArrayDeque(c));
969
970 Collection clone = cloneableClone(c);
971 if (clone != null) {
972 assertSame(c.getClass(), clone.getClass());
973 assertCollectionsEquivalent(c, clone);
974 }
975 try {
976 Collection serialClone = serialClonePossiblyFailing(c);
977 assertSame(c.getClass(), serialClone.getClass());
978 assertCollectionsEquivalent(c, serialClone);
979 } catch (java.io.NotSerializableException acceptable) {}
980 }
981
982 public void testReplaceAllIsNotStructuralModification() {
983 Collection c = impl.emptyCollection();
984 if (!(c instanceof List))
985 return;
986 List list = (List) c;
987 ThreadLocalRandom rnd = ThreadLocalRandom.current();
988 for (int n = rnd.nextInt(2, 10); n--> 0; )
989 list.add(impl.makeElement(rnd.nextInt()));
990 ArrayList copy = new ArrayList(list);
991 int size = list.size(), half = size / 2;
992 Iterator it = list.iterator();
993 for (int i = 0; i < half; i++)
994 assertEquals(it.next(), copy.get(i));
995 list.replaceAll(n -> n);
996 // ConcurrentModificationException must not be thrown here.
997 for (int i = half; i < size; i++)
998 assertEquals(it.next(), copy.get(i));
999 }
1000
1001 // public void testCollection8DebugFail() {
1002 // fail(impl.klazz().getSimpleName());
1003 // }
1004 }