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. */ Collection8Test(CollectionImplementation impl, String methodName)78 Collection8Test(CollectionImplementation impl, String methodName) { 79 super(methodName); 80 this.impl = impl; 81 } 82 testSuite(CollectionImplementation impl)83 public static Test testSuite(CollectionImplementation impl) { 84 return parameterizedTestSuite(Collection8Test.class, 85 CollectionImplementation.class, 86 impl); 87 } 88 bomb()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 DISABLED_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 } 1005