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 () -> q.offer(null, 1L, HOURS),
241 () -> q.put(null));
242 }
243 if (c instanceof BlockingDeque) {
244 BlockingDeque q = (BlockingDeque) c;
245 assertThrows(
246 NullPointerException.class,
247 () -> q.offerFirst(null, 1L, HOURS),
248 () -> q.offerLast(null, 1L, HOURS),
249 () -> q.putFirst(null),
250 () -> q.putLast(null));
251 }
252 }
253
254 public void testNoSuchElementExceptions() {
255 Collection c = impl.emptyCollection();
256 assertThrows(
257 NoSuchElementException.class,
258 () -> c.iterator().next());
259
260 if (c instanceof Queue) {
261 Queue q = (Queue) c;
262 assertThrows(
263 NoSuchElementException.class,
264 () -> q.element(),
265 () -> q.remove());
266 }
267 if (c instanceof Deque) {
268 Deque d = (Deque) c;
269 assertThrows(
270 NoSuchElementException.class,
271 () -> d.getFirst(),
272 () -> d.getLast(),
273 () -> d.removeFirst(),
274 () -> d.removeLast(),
275 () -> d.pop(),
276 () -> d.descendingIterator().next());
277 }
278 if (c instanceof List) {
279 List x = (List) c;
280 assertThrows(
281 NoSuchElementException.class,
282 () -> x.iterator().next(),
283 () -> x.listIterator().next(),
284 () -> x.listIterator(0).next(),
285 () -> x.listIterator().previous(),
286 () -> x.listIterator(0).previous());
287 }
288 }
289
290 public void testRemoveIf() {
291 Collection c = impl.emptyCollection();
292 boolean ordered =
293 c.spliterator().hasCharacteristics(Spliterator.ORDERED);
294 ThreadLocalRandom rnd = ThreadLocalRandom.current();
295 int n = rnd.nextInt(6);
296 for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
297 AtomicReference threwAt = new AtomicReference(null);
298 List orig = rnd.nextBoolean()
299 ? new ArrayList(c)
300 : Arrays.asList(c.toArray());
301
302 // Merely creating an iterator can change ArrayBlockingQueue behavior
303 Iterator it = rnd.nextBoolean() ? c.iterator() : null;
304
305 ArrayList survivors = new ArrayList();
306 ArrayList accepts = new ArrayList();
307 ArrayList rejects = new ArrayList();
308
309 Predicate randomPredicate = e -> {
310 assertNull(threwAt.get());
311 switch (rnd.nextInt(3)) {
312 case 0: accepts.add(e); return true;
313 case 1: rejects.add(e); return false;
314 case 2: threwAt.set(e); throw new ArithmeticException();
315 default: throw new AssertionError();
316 }
317 };
318 try {
319 try {
320 boolean modified = c.removeIf(randomPredicate);
321 assertNull(threwAt.get());
322 assertEquals(modified, accepts.size() > 0);
323 assertEquals(modified, rejects.size() != n);
324 assertEquals(accepts.size() + rejects.size(), n);
325 if (ordered) {
326 assertEquals(rejects,
327 Arrays.asList(c.toArray()));
328 } else {
329 assertEquals(new HashSet(rejects),
330 new HashSet(Arrays.asList(c.toArray())));
331 }
332 } catch (ArithmeticException ok) {
333 assertNotNull(threwAt.get());
334 assertTrue(c.contains(threwAt.get()));
335 }
336 if (it != null && impl.isConcurrent())
337 // check for weakly consistent iterator
338 while (it.hasNext()) assertTrue(orig.contains(it.next()));
339 switch (rnd.nextInt(4)) {
340 case 0: survivors.addAll(c); break;
341 case 1: survivors.addAll(Arrays.asList(c.toArray())); break;
342 case 2: c.forEach(survivors::add); break;
343 case 3: for (Object e : c) survivors.add(e); break;
344 }
345 assertTrue(orig.containsAll(accepts));
346 assertTrue(orig.containsAll(rejects));
347 assertTrue(orig.containsAll(survivors));
348 assertTrue(orig.containsAll(c));
349 assertTrue(c.containsAll(rejects));
350 assertTrue(c.containsAll(survivors));
351 assertTrue(survivors.containsAll(rejects));
352 if (threwAt.get() == null) {
353 assertEquals(n - accepts.size(), c.size());
354 for (Object x : accepts) assertFalse(c.contains(x));
355 } else {
356 // Two acceptable behaviors: entire removeIf call is one
357 // transaction, or each element processed is one transaction.
358 assertTrue(n == c.size() || n == c.size() + accepts.size());
359 int k = 0;
360 for (Object x : accepts) if (c.contains(x)) k++;
361 assertTrue(k == accepts.size() || k == 0);
362 }
363 } catch (Throwable ex) {
364 System.err.println(impl.klazz());
365 // c is at risk of corruption if we got here, so be lenient
366 try { System.err.printf("c=%s%n", c); }
367 catch (Throwable t) { t.printStackTrace(); }
368 System.err.printf("n=%d%n", n);
369 System.err.printf("orig=%s%n", orig);
370 System.err.printf("accepts=%s%n", accepts);
371 System.err.printf("rejects=%s%n", rejects);
372 System.err.printf("survivors=%s%n", survivors);
373 System.err.printf("threwAt=%s%n", threwAt.get());
374 throw ex;
375 }
376 }
377
378 /**
379 * All elements removed in the middle of CONCURRENT traversal.
380 */
381 public void testElementRemovalDuringTraversal() {
382 Collection c = impl.emptyCollection();
383 ThreadLocalRandom rnd = ThreadLocalRandom.current();
384 int n = rnd.nextInt(6);
385 ArrayList copy = new ArrayList();
386 for (int i = 0; i < n; i++) {
387 Object x = impl.makeElement(i);
388 copy.add(x);
389 c.add(x);
390 }
391 ArrayList iterated = new ArrayList();
392 ArrayList spliterated = new ArrayList();
393 Spliterator s = c.spliterator();
394 Iterator it = c.iterator();
395 for (int i = rnd.nextInt(n + 1); --i >= 0; ) {
396 assertTrue(s.tryAdvance(spliterated::add));
397 if (rnd.nextBoolean()) assertTrue(it.hasNext());
398 iterated.add(it.next());
399 }
400 Consumer alwaysThrows = e -> { throw new AssertionError(); };
401 if (s.hasCharacteristics(Spliterator.CONCURRENT)) {
402 c.clear(); // TODO: many more removal methods
403 if (testImplementationDetails
404 && !(c instanceof java.util.concurrent.ArrayBlockingQueue)) {
405 if (rnd.nextBoolean())
406 assertFalse(s.tryAdvance(alwaysThrows));
407 else
408 s.forEachRemaining(alwaysThrows);
409 }
410 if (it.hasNext()) iterated.add(it.next());
411 if (rnd.nextBoolean()) assertIteratorExhausted(it);
412 }
413 assertTrue(copy.containsAll(iterated));
414 assertTrue(copy.containsAll(spliterated));
415 }
416
417 /**
418 * Some elements randomly disappear in the middle of traversal.
419 */
420 public void testRandomElementRemovalDuringTraversal() {
421 Collection c = impl.emptyCollection();
422 ThreadLocalRandom rnd = ThreadLocalRandom.current();
423 int n = rnd.nextInt(6);
424 ArrayList copy = new ArrayList();
425 for (int i = 0; i < n; i++) {
426 Object x = impl.makeElement(i);
427 copy.add(x);
428 c.add(x);
429 }
430 ArrayList iterated = new ArrayList();
431 ArrayList spliterated = new ArrayList();
432 ArrayList removed = new ArrayList();
433 Spliterator s = c.spliterator();
434 Iterator it = c.iterator();
435 if (! (s.hasCharacteristics(Spliterator.CONCURRENT) ||
436 s.hasCharacteristics(Spliterator.IMMUTABLE)))
437 return;
438 for (int i = rnd.nextInt(n + 1); --i >= 0; ) {
439 assertTrue(s.tryAdvance(e -> {}));
440 if (rnd.nextBoolean()) assertTrue(it.hasNext());
441 it.next();
442 }
443 // TODO: many more removal methods
444 if (rnd.nextBoolean()) {
445 for (Iterator z = c.iterator(); z.hasNext(); ) {
446 Object e = z.next();
447 if (rnd.nextBoolean()) {
448 try {
449 z.remove();
450 } catch (UnsupportedOperationException ok) { return; }
451 removed.add(e);
452 }
453 }
454 } else {
455 Predicate randomlyRemove = e -> {
456 if (rnd.nextBoolean()) { removed.add(e); return true; }
457 else return false;
458 };
459 c.removeIf(randomlyRemove);
460 }
461 s.forEachRemaining(spliterated::add);
462 while (it.hasNext())
463 iterated.add(it.next());
464 assertTrue(copy.containsAll(iterated));
465 assertTrue(copy.containsAll(spliterated));
466 assertTrue(copy.containsAll(removed));
467 if (s.hasCharacteristics(Spliterator.CONCURRENT)) {
468 ArrayList iteratedAndRemoved = new ArrayList(iterated);
469 ArrayList spliteratedAndRemoved = new ArrayList(spliterated);
470 iteratedAndRemoved.retainAll(removed);
471 spliteratedAndRemoved.retainAll(removed);
472 assertTrue(iteratedAndRemoved.size() <= 1);
473 assertTrue(spliteratedAndRemoved.size() <= 1);
474 if (testImplementationDetails
475 && !(c instanceof java.util.concurrent.ArrayBlockingQueue))
476 assertTrue(spliteratedAndRemoved.isEmpty());
477 }
478 }
479
480 /**
481 * Various ways of traversing a collection yield same elements
482 */
483 public void testTraversalEquivalence() {
484 Collection c = impl.emptyCollection();
485 ThreadLocalRandom rnd = ThreadLocalRandom.current();
486 int n = rnd.nextInt(6);
487 for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
488 ArrayList iterated = new ArrayList();
489 ArrayList iteratedForEachRemaining = new ArrayList();
490 ArrayList tryAdvanced = new ArrayList();
491 ArrayList spliterated = new ArrayList();
492 ArrayList splitonced = new ArrayList();
493 ArrayList forEached = new ArrayList();
494 ArrayList streamForEached = new ArrayList();
495 ConcurrentLinkedQueue parallelStreamForEached = new ConcurrentLinkedQueue();
496 ArrayList removeIfed = new ArrayList();
497 for (Object x : c) iterated.add(x);
498 c.iterator().forEachRemaining(iteratedForEachRemaining::add);
499 for (Spliterator s = c.spliterator();
500 s.tryAdvance(tryAdvanced::add); ) {}
501 c.spliterator().forEachRemaining(spliterated::add);
502 { // trySplit returns "strict prefix"
503 Spliterator s1 = c.spliterator(), s2 = s1.trySplit();
504 if (s2 != null) s2.forEachRemaining(splitonced::add);
505 s1.forEachRemaining(splitonced::add);
506 }
507 c.forEach(forEached::add);
508 c.stream().forEach(streamForEached::add);
509 c.parallelStream().forEach(parallelStreamForEached::add);
510 c.removeIf(e -> { removeIfed.add(e); return false; });
511 boolean ordered =
512 c.spliterator().hasCharacteristics(Spliterator.ORDERED);
513 if (c instanceof List || c instanceof Deque)
514 assertTrue(ordered);
515 HashSet cset = new HashSet(c);
516 assertEquals(cset, new HashSet(parallelStreamForEached));
517 if (ordered) {
518 assertEquals(iterated, iteratedForEachRemaining);
519 assertEquals(iterated, tryAdvanced);
520 assertEquals(iterated, spliterated);
521 assertEquals(iterated, splitonced);
522 assertEquals(iterated, forEached);
523 assertEquals(iterated, streamForEached);
524 assertEquals(iterated, removeIfed);
525 } else {
526 assertEquals(cset, new HashSet(iterated));
527 assertEquals(cset, new HashSet(iteratedForEachRemaining));
528 assertEquals(cset, new HashSet(tryAdvanced));
529 assertEquals(cset, new HashSet(spliterated));
530 assertEquals(cset, new HashSet(splitonced));
531 assertEquals(cset, new HashSet(forEached));
532 assertEquals(cset, new HashSet(streamForEached));
533 assertEquals(cset, new HashSet(removeIfed));
534 }
535 if (c instanceof Deque) {
536 Deque d = (Deque) c;
537 ArrayList descending = new ArrayList();
538 ArrayList descendingForEachRemaining = new ArrayList();
539 for (Iterator it = d.descendingIterator(); it.hasNext(); )
540 descending.add(it.next());
541 d.descendingIterator().forEachRemaining(
542 e -> descendingForEachRemaining.add(e));
543 Collections.reverse(descending);
544 Collections.reverse(descendingForEachRemaining);
545 assertEquals(iterated, descending);
546 assertEquals(iterated, descendingForEachRemaining);
547 }
548 }
549
550 /**
551 * Iterator.forEachRemaining has same behavior as Iterator's
552 * default implementation.
553 */
554 public void testForEachRemainingConsistentWithDefaultImplementation() {
555 Collection c = impl.emptyCollection();
556 if (!testImplementationDetails
557 || c.getClass() == java.util.LinkedList.class)
558 return;
559 ThreadLocalRandom rnd = ThreadLocalRandom.current();
560 int n = 1 + rnd.nextInt(3);
561 for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
562 ArrayList iterated = new ArrayList();
563 ArrayList iteratedForEachRemaining = new ArrayList();
564 Iterator it1 = c.iterator();
565 Iterator it2 = c.iterator();
566 assertTrue(it1.hasNext());
567 assertTrue(it2.hasNext());
568 c.clear();
569 Object r1, r2;
570 try {
571 while (it1.hasNext()) iterated.add(it1.next());
572 r1 = iterated;
573 } catch (ConcurrentModificationException ex) {
574 r1 = ConcurrentModificationException.class;
575 assertFalse(impl.isConcurrent());
576 }
577 try {
578 it2.forEachRemaining(iteratedForEachRemaining::add);
579 r2 = iteratedForEachRemaining;
580 } catch (ConcurrentModificationException ex) {
581 r2 = ConcurrentModificationException.class;
582 assertFalse(impl.isConcurrent());
583 }
584 assertEquals(r1, r2);
585 }
586
587 /**
588 * Calling Iterator#remove() after Iterator#forEachRemaining
589 * should (maybe) remove last element
590 */
591 public void testRemoveAfterForEachRemaining() {
592 Collection c = impl.emptyCollection();
593 ThreadLocalRandom rnd = ThreadLocalRandom.current();
594 ArrayList copy = new ArrayList();
595 boolean ordered = c.spliterator().hasCharacteristics(Spliterator.ORDERED);
596 testCollection: {
597 int n = 3 + rnd.nextInt(2);
598 for (int i = 0; i < n; i++) {
599 Object x = impl.makeElement(i);
600 c.add(x);
601 copy.add(x);
602 }
603 Iterator it = c.iterator();
604 if (ordered) {
605 if (rnd.nextBoolean()) assertTrue(it.hasNext());
606 assertEquals(impl.makeElement(0), it.next());
607 if (rnd.nextBoolean()) assertTrue(it.hasNext());
608 assertEquals(impl.makeElement(1), it.next());
609 } else {
610 if (rnd.nextBoolean()) assertTrue(it.hasNext());
611 assertTrue(copy.contains(it.next()));
612 if (rnd.nextBoolean()) assertTrue(it.hasNext());
613 assertTrue(copy.contains(it.next()));
614 }
615 if (rnd.nextBoolean()) assertTrue(it.hasNext());
616 it.forEachRemaining(
617 e -> {
618 assertTrue(c.contains(e));
619 assertTrue(copy.contains(e));});
620 if (testImplementationDetails) {
621 if (c instanceof java.util.concurrent.ArrayBlockingQueue) {
622 assertIteratorExhausted(it);
623 } else {
624 try { it.remove(); }
625 catch (UnsupportedOperationException ok) {
626 break testCollection;
627 }
628 assertEquals(n - 1, c.size());
629 if (ordered) {
630 for (int i = 0; i < n - 1; i++)
631 assertTrue(c.contains(impl.makeElement(i)));
632 assertFalse(c.contains(impl.makeElement(n - 1)));
633 }
634 }
635 }
636 }
637 if (c instanceof Deque) {
638 Deque d = (Deque) impl.emptyCollection();
639 assertTrue(ordered);
640 int n = 3 + rnd.nextInt(2);
641 for (int i = 0; i < n; i++) d.add(impl.makeElement(i));
642 Iterator it = d.descendingIterator();
643 assertTrue(it.hasNext());
644 assertEquals(impl.makeElement(n - 1), it.next());
645 assertTrue(it.hasNext());
646 assertEquals(impl.makeElement(n - 2), it.next());
647 it.forEachRemaining(e -> assertTrue(c.contains(e)));
648 if (testImplementationDetails) {
649 it.remove();
650 assertEquals(n - 1, d.size());
651 for (int i = 1; i < n; i++)
652 assertTrue(d.contains(impl.makeElement(i)));
653 assertFalse(d.contains(impl.makeElement(0)));
654 }
655 }
656 }
657
658 /**
659 * stream().forEach returns elements in the collection
660 */
661 public void testStreamForEach() throws Throwable {
662 final Collection c = impl.emptyCollection();
663 final Object x = impl.makeElement(1);
664 final Object y = impl.makeElement(2);
665 final ArrayList found = new ArrayList();
666 Consumer<Object> spy = o -> found.add(o);
667 c.stream().forEach(spy);
668 assertTrue(found.isEmpty());
669
670 assertTrue(c.add(x));
671 c.stream().forEach(spy);
672 assertEquals(Collections.singletonList(x), found);
673 found.clear();
674
675 assertTrue(c.add(y));
676 c.stream().forEach(spy);
677 assertEquals(2, found.size());
678 assertTrue(found.contains(x));
679 assertTrue(found.contains(y));
680 found.clear();
681
682 c.clear();
683 c.stream().forEach(spy);
684 assertTrue(found.isEmpty());
685 }
686
687 public void testStreamForEachConcurrentStressTest() throws Throwable {
688 if (!impl.isConcurrent()) return;
689 final Collection c = impl.emptyCollection();
690 final long testDurationMillis = timeoutMillis();
691 final AtomicBoolean done = new AtomicBoolean(false);
692 final Object elt = impl.makeElement(1);
693 final Future<?> f1, f2;
694 final ExecutorService pool = Executors.newCachedThreadPool();
695 try (PoolCleaner cleaner = cleaner(pool, done)) {
696 final CountDownLatch threadsStarted = new CountDownLatch(2);
697 Runnable checkElt = () -> {
698 threadsStarted.countDown();
699 while (!done.get())
700 c.stream().forEach(x -> assertSame(x, elt)); };
701 Runnable addRemove = () -> {
702 threadsStarted.countDown();
703 while (!done.get()) {
704 assertTrue(c.add(elt));
705 assertTrue(c.remove(elt));
706 }};
707 f1 = pool.submit(checkElt);
708 f2 = pool.submit(addRemove);
709 Thread.sleep(testDurationMillis);
710 }
711 assertNull(f1.get(0L, MILLISECONDS));
712 assertNull(f2.get(0L, MILLISECONDS));
713 }
714
715 /**
716 * collection.forEach returns elements in the collection
717 */
718 public void testForEach() throws Throwable {
719 final Collection c = impl.emptyCollection();
720 final Object x = impl.makeElement(1);
721 final Object y = impl.makeElement(2);
722 final ArrayList found = new ArrayList();
723 Consumer<Object> spy = o -> found.add(o);
724 c.forEach(spy);
725 assertTrue(found.isEmpty());
726
727 assertTrue(c.add(x));
728 c.forEach(spy);
729 assertEquals(Collections.singletonList(x), found);
730 found.clear();
731
732 assertTrue(c.add(y));
733 c.forEach(spy);
734 assertEquals(2, found.size());
735 assertTrue(found.contains(x));
736 assertTrue(found.contains(y));
737 found.clear();
738
739 c.clear();
740 c.forEach(spy);
741 assertTrue(found.isEmpty());
742 }
743
744 /** TODO: promote to a common utility */
745 static <T> T chooseOne(T ... ts) {
746 return ts[ThreadLocalRandom.current().nextInt(ts.length)];
747 }
748
749 /** TODO: more random adders and removers */
750 static <E> Runnable adderRemover(Collection<E> c, E e) {
751 return chooseOne(
752 () -> {
753 assertTrue(c.add(e));
754 assertTrue(c.contains(e));
755 assertTrue(c.remove(e));
756 assertFalse(c.contains(e));
757 },
758 () -> {
759 assertTrue(c.add(e));
760 assertTrue(c.contains(e));
761 assertTrue(c.removeIf(x -> x == e));
762 assertFalse(c.contains(e));
763 },
764 () -> {
765 assertTrue(c.add(e));
766 assertTrue(c.contains(e));
767 for (Iterator it = c.iterator();; )
768 if (it.next() == e) {
769 try { it.remove(); }
770 catch (UnsupportedOperationException ok) {
771 c.remove(e);
772 }
773 break;
774 }
775 assertFalse(c.contains(e));
776 });
777 }
778
779 /**
780 * Concurrent Spliterators, once exhausted, stay exhausted.
781 */
782 public void testStickySpliteratorExhaustion() throws Throwable {
783 if (!impl.isConcurrent()) return;
784 if (!testImplementationDetails) return;
785 final ThreadLocalRandom rnd = ThreadLocalRandom.current();
786 final Consumer alwaysThrows = e -> { throw new AssertionError(); };
787 final Collection c = impl.emptyCollection();
788 final Spliterator s = c.spliterator();
789 if (rnd.nextBoolean()) {
790 assertFalse(s.tryAdvance(alwaysThrows));
791 } else {
792 s.forEachRemaining(alwaysThrows);
793 }
794 final Object one = impl.makeElement(1);
795 // Spliterator should not notice added element
796 c.add(one);
797 if (rnd.nextBoolean()) {
798 assertFalse(s.tryAdvance(alwaysThrows));
799 } else {
800 s.forEachRemaining(alwaysThrows);
801 }
802 }
803
804 /**
805 * Motley crew of threads concurrently randomly hammer the collection.
806 */
807 public void testDetectRaces() throws Throwable {
808 if (!impl.isConcurrent()) return;
809 final ThreadLocalRandom rnd = ThreadLocalRandom.current();
810 final Collection c = impl.emptyCollection();
811 final long testDurationMillis
812 = expensiveTests ? LONG_DELAY_MS : timeoutMillis();
813 final AtomicBoolean done = new AtomicBoolean(false);
814 final Object one = impl.makeElement(1);
815 final Object two = impl.makeElement(2);
816 final Consumer checkSanity = x -> assertTrue(x == one || x == two);
817 final Consumer<Object[]> checkArraySanity = array -> {
818 // assertTrue(array.length <= 2); // duplicates are permitted
819 for (Object x : array) assertTrue(x == one || x == two);
820 };
821 final Object[] emptyArray =
822 (Object[]) java.lang.reflect.Array.newInstance(one.getClass(), 0);
823 final List<Future<?>> futures;
824 final Phaser threadsStarted = new Phaser(1); // register this thread
825 final Runnable[] frobbers = {
826 () -> c.forEach(checkSanity),
827 () -> c.stream().forEach(checkSanity),
828 () -> c.parallelStream().forEach(checkSanity),
829 () -> c.spliterator().trySplit(),
830 () -> {
831 Spliterator s = c.spliterator();
832 s.tryAdvance(checkSanity);
833 s.trySplit();
834 },
835 () -> {
836 Spliterator s = c.spliterator();
837 do {} while (s.tryAdvance(checkSanity));
838 },
839 () -> { for (Object x : c) checkSanity.accept(x); },
840 () -> checkArraySanity.accept(c.toArray()),
841 () -> checkArraySanity.accept(c.toArray(emptyArray)),
842 () -> {
843 Object[] a = new Object[5];
844 Object three = impl.makeElement(3);
845 Arrays.fill(a, 0, a.length, three);
846 Object[] x = c.toArray(a);
847 if (x == a)
848 for (int i = 0; i < a.length && a[i] != null; i++)
849 checkSanity.accept(a[i]);
850 // A careful reading of the spec does not support:
851 // for (i++; i < a.length; i++) assertSame(three, a[i]);
852 else
853 checkArraySanity.accept(x);
854 },
855 adderRemover(c, one),
856 adderRemover(c, two),
857 };
858 final List<Runnable> tasks =
859 Arrays.stream(frobbers)
860 .filter(task -> rnd.nextBoolean()) // random subset
861 .map(task -> (Runnable) () -> {
862 threadsStarted.arriveAndAwaitAdvance();
863 while (!done.get())
864 task.run();
865 })
866 .collect(Collectors.toList());
867 final ExecutorService pool = Executors.newCachedThreadPool();
868 try (PoolCleaner cleaner = cleaner(pool, done)) {
869 threadsStarted.bulkRegister(tasks.size());
870 futures = tasks.stream()
871 .map(pool::submit)
872 .collect(Collectors.toList());
873 threadsStarted.arriveAndDeregister();
874 Thread.sleep(testDurationMillis);
875 }
876 for (Future future : futures)
877 assertNull(future.get(0L, MILLISECONDS));
878 }
879
880 /**
881 * Spliterators are either IMMUTABLE or truly late-binding or, if
882 * concurrent, use the same "late-binding style" of returning
883 * elements added between creation and first use.
884 */
885 public void testLateBindingStyle() {
886 if (!testImplementationDetails) return;
887 if (impl.klazz() == ArrayList.class) return; // for jdk8
888 // Immutable (snapshot) spliterators are exempt
889 if (impl.emptyCollection().spliterator()
890 .hasCharacteristics(Spliterator.IMMUTABLE))
891 return;
892 final Object one = impl.makeElement(1);
893 {
894 final Collection c = impl.emptyCollection();
895 final Spliterator split = c.spliterator();
896 c.add(one);
897 assertTrue(split.tryAdvance(e -> { assertSame(e, one); }));
898 assertFalse(split.tryAdvance(e -> { throw new AssertionError(); }));
899 assertTrue(c.contains(one));
900 }
901 {
902 final AtomicLong count = new AtomicLong(0);
903 final Collection c = impl.emptyCollection();
904 final Spliterator split = c.spliterator();
905 c.add(one);
906 split.forEachRemaining(
907 e -> { assertSame(e, one); count.getAndIncrement(); });
908 assertEquals(1L, count.get());
909 assertFalse(split.tryAdvance(e -> { throw new AssertionError(); }));
910 assertTrue(c.contains(one));
911 }
912 }
913
914 /**
915 * Spliterator.getComparator throws IllegalStateException iff the
916 * spliterator does not report SORTED.
917 */
918 public void testGetComparator_IllegalStateException() {
919 Collection c = impl.emptyCollection();
920 Spliterator s = c.spliterator();
921 boolean reportsSorted = s.hasCharacteristics(Spliterator.SORTED);
922 try {
923 s.getComparator();
924 assertTrue(reportsSorted);
925 } catch (IllegalStateException ex) {
926 assertFalse(reportsSorted);
927 }
928 }
929
930 public void testCollectionCopies() throws Exception {
931 ThreadLocalRandom rnd = ThreadLocalRandom.current();
932 Collection c = impl.emptyCollection();
933 for (int n = rnd.nextInt(4); n--> 0; )
934 c.add(impl.makeElement(rnd.nextInt()));
935 assertEquals(c, c);
936 if (c instanceof List)
937 assertCollectionsEquals(c, new ArrayList(c));
938 else if (c instanceof Set)
939 assertCollectionsEquals(c, new HashSet(c));
940 else if (c instanceof Deque)
941 assertCollectionsEquivalent(c, new ArrayDeque(c));
942
943 Collection clone = cloneableClone(c);
944 if (clone != null) {
945 assertSame(c.getClass(), clone.getClass());
946 assertCollectionsEquivalent(c, clone);
947 }
948 try {
949 Collection serialClone = serialClonePossiblyFailing(c);
950 assertSame(c.getClass(), serialClone.getClass());
951 assertCollectionsEquivalent(c, serialClone);
952 } catch (java.io.NotSerializableException acceptable) {}
953 }
954
955 /**
956 * TODO: move out of limbo
957 * 8203662: remove increment of modCount from ArrayList and Vector replaceAll()
958 */
959 public void DISABLED_testReplaceAllIsNotStructuralModification() {
960 Collection c = impl.emptyCollection();
961 if (!(c instanceof List))
962 return;
963 List list = (List) c;
964 ThreadLocalRandom rnd = ThreadLocalRandom.current();
965 for (int n = rnd.nextInt(2, 10); n--> 0; )
966 list.add(impl.makeElement(rnd.nextInt()));
967 ArrayList copy = new ArrayList(list);
968 int size = list.size(), half = size / 2;
969 Iterator it = list.iterator();
970 for (int i = 0; i < half; i++)
971 assertEquals(it.next(), copy.get(i));
972 list.replaceAll(n -> n);
973 // ConcurrentModificationException must not be thrown here.
974 for (int i = half; i < size; i++)
975 assertEquals(it.next(), copy.get(i));
976 }
977
978 // public void testCollection8DebugFail() {
979 // fail(impl.klazz().getSimpleName());
980 // }
981 }