/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* * This file is available under and governed by the GNU General Public * License version 2 only, as published by the Free Software Foundation. * However, the following notice accompanied the original version of this * file: * * Written by Doug Lea and Martin Buchholz with assistance from * members of JCP JSR-166 Expert Group and released to the public * domain, as explained at * http://creativecommons.org/publicdomain/zero/1.0/ */ import static java.util.concurrent.TimeUnit.HOURS; import static java.util.concurrent.TimeUnit.MILLISECONDS; import java.util.ArrayDeque; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.ConcurrentModificationException; import java.util.Deque; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.NoSuchElementException; import java.util.Queue; import java.util.Set; import java.util.Spliterator; import java.util.concurrent.BlockingDeque; import java.util.concurrent.BlockingQueue; import java.util.concurrent.ConcurrentLinkedQueue; import java.util.concurrent.CountDownLatch; import java.util.concurrent.Executors; import java.util.concurrent.ExecutorService; import java.util.concurrent.Future; import java.util.concurrent.Phaser; import java.util.concurrent.ThreadLocalRandom; import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicLong; import java.util.concurrent.atomic.AtomicReference; import java.util.function.Consumer; import java.util.function.Predicate; import java.util.stream.Collectors; import junit.framework.Test; /** * Contains tests applicable to all jdk8+ Collection implementations. * An extension of CollectionTest. */ public class Collection8Test extends JSR166TestCase { final CollectionImplementation impl; /** Tests are parameterized by a Collection implementation. */ Collection8Test(CollectionImplementation impl, String methodName) { super(methodName); this.impl = impl; } public static Test testSuite(CollectionImplementation impl) { return parameterizedTestSuite(Collection8Test.class, CollectionImplementation.class, impl); } Object bomb() { return new Object() { @Override public boolean equals(Object x) { throw new AssertionError(); } @Override public int hashCode() { throw new AssertionError(); } @Override public String toString() { throw new AssertionError(); } }; } /** Checks properties of empty collections. */ public void testEmptyMeansEmpty() throws Throwable { Collection c = impl.emptyCollection(); emptyMeansEmpty(c); if (c instanceof java.io.Serializable) { try { emptyMeansEmpty(serialClonePossiblyFailing(c)); } catch (java.io.NotSerializableException ex) { // excusable when we have a serializable wrapper around // a non-serializable collection, as can happen with: // Vector.subList() => wrapped AbstractList$RandomAccessSubList if (testImplementationDetails && (! c.getClass().getName().matches( "java.util.Collections.*"))) throw ex; } } Collection clone = cloneableClone(c); if (clone != null) emptyMeansEmpty(clone); } void emptyMeansEmpty(Collection c) throws InterruptedException { assertTrue(c.isEmpty()); assertEquals(0, c.size()); assertEquals("[]", c.toString()); if (c instanceof List) { List x = (List) c; assertEquals(1, x.hashCode()); assertEquals(x, Collections.emptyList()); assertEquals(Collections.emptyList(), x); assertEquals(-1, x.indexOf(impl.makeElement(86))); assertEquals(-1, x.lastIndexOf(impl.makeElement(99))); assertThrows( IndexOutOfBoundsException.class, () -> x.get(0), () -> x.set(0, impl.makeElement(42))); } else if (c instanceof Set) { assertEquals(0, c.hashCode()); assertEquals(c, Collections.emptySet()); assertEquals(Collections.emptySet(), c); } { Object[] a = c.toArray(); assertEquals(0, a.length); assertSame(Object[].class, a.getClass()); } { Object[] a = new Object[0]; assertSame(a, c.toArray(a)); } { Integer[] a = new Integer[0]; assertSame(a, c.toArray(a)); } { Integer[] a = { 1, 2, 3}; assertSame(a, c.toArray(a)); assertNull(a[0]); assertSame(2, a[1]); assertSame(3, a[2]); } assertIteratorExhausted(c.iterator()); Consumer alwaysThrows = e -> { throw new AssertionError(); }; c.forEach(alwaysThrows); c.iterator().forEachRemaining(alwaysThrows); c.spliterator().forEachRemaining(alwaysThrows); assertFalse(c.spliterator().tryAdvance(alwaysThrows)); if (c.spliterator().hasCharacteristics(Spliterator.SIZED)) assertEquals(0, c.spliterator().estimateSize()); assertFalse(c.contains(bomb())); assertFalse(c.remove(bomb())); if (c instanceof Queue) { Queue q = (Queue) c; assertNull(q.peek()); assertNull(q.poll()); } if (c instanceof Deque) { Deque d = (Deque) c; assertNull(d.peekFirst()); assertNull(d.peekLast()); assertNull(d.pollFirst()); assertNull(d.pollLast()); assertIteratorExhausted(d.descendingIterator()); d.descendingIterator().forEachRemaining(alwaysThrows); assertFalse(d.removeFirstOccurrence(bomb())); assertFalse(d.removeLastOccurrence(bomb())); } if (c instanceof BlockingQueue) { BlockingQueue q = (BlockingQueue) c; assertNull(q.poll(randomExpiredTimeout(), randomTimeUnit())); } if (c instanceof BlockingDeque) { BlockingDeque q = (BlockingDeque) c; assertNull(q.pollFirst(randomExpiredTimeout(), randomTimeUnit())); assertNull(q.pollLast(randomExpiredTimeout(), randomTimeUnit())); } } public void testNullPointerExceptions() throws InterruptedException { Collection c = impl.emptyCollection(); assertThrows( NullPointerException.class, () -> c.addAll(null), () -> c.containsAll(null), () -> c.retainAll(null), () -> c.removeAll(null), () -> c.removeIf(null), () -> c.forEach(null), () -> c.iterator().forEachRemaining(null), () -> c.spliterator().forEachRemaining(null), () -> c.spliterator().tryAdvance(null), () -> c.toArray(null)); if (!impl.permitsNulls()) { assertThrows( NullPointerException.class, () -> c.add(null)); } if (!impl.permitsNulls() && c instanceof Queue) { Queue q = (Queue) c; assertThrows( NullPointerException.class, () -> q.offer(null)); } if (!impl.permitsNulls() && c instanceof Deque) { Deque d = (Deque) c; assertThrows( NullPointerException.class, () -> d.addFirst(null), () -> d.addLast(null), () -> d.offerFirst(null), () -> d.offerLast(null), () -> d.push(null), () -> d.descendingIterator().forEachRemaining(null)); } if (c instanceof BlockingQueue) { BlockingQueue q = (BlockingQueue) c; assertThrows( NullPointerException.class, () -> { try { q.offer(null, 1L, HOURS); } catch (InterruptedException ex) { throw new AssertionError(ex); }}, () -> { try { q.put(null); } catch (InterruptedException ex) { throw new AssertionError(ex); }}); } if (c instanceof BlockingDeque) { BlockingDeque q = (BlockingDeque) c; assertThrows( NullPointerException.class, () -> { try { q.offerFirst(null, 1L, HOURS); } catch (InterruptedException ex) { throw new AssertionError(ex); }}, () -> { try { q.offerLast(null, 1L, HOURS); } catch (InterruptedException ex) { throw new AssertionError(ex); }}, () -> { try { q.putFirst(null); } catch (InterruptedException ex) { throw new AssertionError(ex); }}, () -> { try { q.putLast(null); } catch (InterruptedException ex) { throw new AssertionError(ex); }}); } } public void testNoSuchElementExceptions() { Collection c = impl.emptyCollection(); assertThrows( NoSuchElementException.class, () -> c.iterator().next()); if (c instanceof Queue) { Queue q = (Queue) c; assertThrows( NoSuchElementException.class, () -> q.element(), () -> q.remove()); } if (c instanceof Deque) { Deque d = (Deque) c; assertThrows( NoSuchElementException.class, () -> d.getFirst(), () -> d.getLast(), () -> d.removeFirst(), () -> d.removeLast(), () -> d.pop(), () -> d.descendingIterator().next()); } if (c instanceof List) { List x = (List) c; assertThrows( NoSuchElementException.class, () -> x.iterator().next(), () -> x.listIterator().next(), () -> x.listIterator(0).next(), () -> x.listIterator().previous(), () -> x.listIterator(0).previous()); } } public void testRemoveIf() { Collection c = impl.emptyCollection(); boolean ordered = c.spliterator().hasCharacteristics(Spliterator.ORDERED); ThreadLocalRandom rnd = ThreadLocalRandom.current(); int n = rnd.nextInt(6); for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); AtomicReference threwAt = new AtomicReference(null); List orig = rnd.nextBoolean() ? new ArrayList(c) : Arrays.asList(c.toArray()); // Merely creating an iterator can change ArrayBlockingQueue behavior Iterator it = rnd.nextBoolean() ? c.iterator() : null; ArrayList survivors = new ArrayList(); ArrayList accepts = new ArrayList(); ArrayList rejects = new ArrayList(); Predicate randomPredicate = e -> { assertNull(threwAt.get()); switch (rnd.nextInt(3)) { case 0: accepts.add(e); return true; case 1: rejects.add(e); return false; case 2: threwAt.set(e); throw new ArithmeticException(); default: throw new AssertionError(); } }; try { try { boolean modified = c.removeIf(randomPredicate); assertNull(threwAt.get()); assertEquals(modified, accepts.size() > 0); assertEquals(modified, rejects.size() != n); assertEquals(accepts.size() + rejects.size(), n); if (ordered) { assertEquals(rejects, Arrays.asList(c.toArray())); } else { assertEquals(new HashSet(rejects), new HashSet(Arrays.asList(c.toArray()))); } } catch (ArithmeticException ok) { assertNotNull(threwAt.get()); assertTrue(c.contains(threwAt.get())); } if (it != null && impl.isConcurrent()) // check for weakly consistent iterator while (it.hasNext()) assertTrue(orig.contains(it.next())); switch (rnd.nextInt(4)) { case 0: survivors.addAll(c); break; case 1: survivors.addAll(Arrays.asList(c.toArray())); break; case 2: c.forEach(survivors::add); break; case 3: for (Object e : c) survivors.add(e); break; } assertTrue(orig.containsAll(accepts)); assertTrue(orig.containsAll(rejects)); assertTrue(orig.containsAll(survivors)); assertTrue(orig.containsAll(c)); assertTrue(c.containsAll(rejects)); assertTrue(c.containsAll(survivors)); assertTrue(survivors.containsAll(rejects)); if (threwAt.get() == null) { assertEquals(n - accepts.size(), c.size()); for (Object x : accepts) assertFalse(c.contains(x)); } else { // Two acceptable behaviors: entire removeIf call is one // transaction, or each element processed is one transaction. assertTrue(n == c.size() || n == c.size() + accepts.size()); int k = 0; for (Object x : accepts) if (c.contains(x)) k++; assertTrue(k == accepts.size() || k == 0); } } catch (Throwable ex) { System.err.println(impl.klazz()); // c is at risk of corruption if we got here, so be lenient try { System.err.printf("c=%s%n", c); } catch (Throwable t) { t.printStackTrace(); } System.err.printf("n=%d%n", n); System.err.printf("orig=%s%n", orig); System.err.printf("accepts=%s%n", accepts); System.err.printf("rejects=%s%n", rejects); System.err.printf("survivors=%s%n", survivors); System.err.printf("threwAt=%s%n", threwAt.get()); throw ex; } } /** * All elements removed in the middle of CONCURRENT traversal. */ public void testElementRemovalDuringTraversal() { Collection c = impl.emptyCollection(); ThreadLocalRandom rnd = ThreadLocalRandom.current(); int n = rnd.nextInt(6); ArrayList copy = new ArrayList(); for (int i = 0; i < n; i++) { Object x = impl.makeElement(i); copy.add(x); c.add(x); } ArrayList iterated = new ArrayList(); ArrayList spliterated = new ArrayList(); Spliterator s = c.spliterator(); Iterator it = c.iterator(); for (int i = rnd.nextInt(n + 1); --i >= 0; ) { assertTrue(s.tryAdvance(spliterated::add)); if (rnd.nextBoolean()) assertTrue(it.hasNext()); iterated.add(it.next()); } Consumer alwaysThrows = e -> { throw new AssertionError(); }; if (s.hasCharacteristics(Spliterator.CONCURRENT)) { c.clear(); // TODO: many more removal methods if (testImplementationDetails && !(c instanceof java.util.concurrent.ArrayBlockingQueue)) { if (rnd.nextBoolean()) assertFalse(s.tryAdvance(alwaysThrows)); else s.forEachRemaining(alwaysThrows); } if (it.hasNext()) iterated.add(it.next()); if (rnd.nextBoolean()) assertIteratorExhausted(it); } assertTrue(copy.containsAll(iterated)); assertTrue(copy.containsAll(spliterated)); } /** * Some elements randomly disappear in the middle of traversal. */ public void testRandomElementRemovalDuringTraversal() { Collection c = impl.emptyCollection(); ThreadLocalRandom rnd = ThreadLocalRandom.current(); int n = rnd.nextInt(6); ArrayList copy = new ArrayList(); for (int i = 0; i < n; i++) { Object x = impl.makeElement(i); copy.add(x); c.add(x); } ArrayList iterated = new ArrayList(); ArrayList spliterated = new ArrayList(); ArrayList removed = new ArrayList(); Spliterator s = c.spliterator(); Iterator it = c.iterator(); if (! (s.hasCharacteristics(Spliterator.CONCURRENT) || s.hasCharacteristics(Spliterator.IMMUTABLE))) return; for (int i = rnd.nextInt(n + 1); --i >= 0; ) { assertTrue(s.tryAdvance(e -> {})); if (rnd.nextBoolean()) assertTrue(it.hasNext()); it.next(); } Consumer alwaysThrows = e -> { throw new AssertionError(); }; // TODO: many more removal methods if (rnd.nextBoolean()) { for (Iterator z = c.iterator(); z.hasNext(); ) { Object e = z.next(); if (rnd.nextBoolean()) { try { z.remove(); } catch (UnsupportedOperationException ok) { return; } removed.add(e); } } } else { Predicate randomlyRemove = e -> { if (rnd.nextBoolean()) { removed.add(e); return true; } else return false; }; c.removeIf(randomlyRemove); } s.forEachRemaining(spliterated::add); while (it.hasNext()) iterated.add(it.next()); assertTrue(copy.containsAll(iterated)); assertTrue(copy.containsAll(spliterated)); assertTrue(copy.containsAll(removed)); if (s.hasCharacteristics(Spliterator.CONCURRENT)) { ArrayList iteratedAndRemoved = new ArrayList(iterated); ArrayList spliteratedAndRemoved = new ArrayList(spliterated); iteratedAndRemoved.retainAll(removed); spliteratedAndRemoved.retainAll(removed); assertTrue(iteratedAndRemoved.size() <= 1); assertTrue(spliteratedAndRemoved.size() <= 1); if (testImplementationDetails && !(c instanceof java.util.concurrent.ArrayBlockingQueue)) assertTrue(spliteratedAndRemoved.isEmpty()); } } /** * Various ways of traversing a collection yield same elements */ public void testTraversalEquivalence() { Collection c = impl.emptyCollection(); ThreadLocalRandom rnd = ThreadLocalRandom.current(); int n = rnd.nextInt(6); for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); ArrayList iterated = new ArrayList(); ArrayList iteratedForEachRemaining = new ArrayList(); ArrayList tryAdvanced = new ArrayList(); ArrayList spliterated = new ArrayList(); ArrayList splitonced = new ArrayList(); ArrayList forEached = new ArrayList(); ArrayList streamForEached = new ArrayList(); ConcurrentLinkedQueue parallelStreamForEached = new ConcurrentLinkedQueue(); ArrayList removeIfed = new ArrayList(); for (Object x : c) iterated.add(x); c.iterator().forEachRemaining(iteratedForEachRemaining::add); for (Spliterator s = c.spliterator(); s.tryAdvance(tryAdvanced::add); ) {} c.spliterator().forEachRemaining(spliterated::add); { // trySplit returns "strict prefix" Spliterator s1 = c.spliterator(), s2 = s1.trySplit(); if (s2 != null) s2.forEachRemaining(splitonced::add); s1.forEachRemaining(splitonced::add); } c.forEach(forEached::add); c.stream().forEach(streamForEached::add); c.parallelStream().forEach(parallelStreamForEached::add); c.removeIf(e -> { removeIfed.add(e); return false; }); boolean ordered = c.spliterator().hasCharacteristics(Spliterator.ORDERED); if (c instanceof List || c instanceof Deque) assertTrue(ordered); HashSet cset = new HashSet(c); assertEquals(cset, new HashSet(parallelStreamForEached)); if (ordered) { assertEquals(iterated, iteratedForEachRemaining); assertEquals(iterated, tryAdvanced); assertEquals(iterated, spliterated); assertEquals(iterated, splitonced); assertEquals(iterated, forEached); assertEquals(iterated, streamForEached); assertEquals(iterated, removeIfed); } else { assertEquals(cset, new HashSet(iterated)); assertEquals(cset, new HashSet(iteratedForEachRemaining)); assertEquals(cset, new HashSet(tryAdvanced)); assertEquals(cset, new HashSet(spliterated)); assertEquals(cset, new HashSet(splitonced)); assertEquals(cset, new HashSet(forEached)); assertEquals(cset, new HashSet(streamForEached)); assertEquals(cset, new HashSet(removeIfed)); } if (c instanceof Deque) { Deque d = (Deque) c; ArrayList descending = new ArrayList(); ArrayList descendingForEachRemaining = new ArrayList(); for (Iterator it = d.descendingIterator(); it.hasNext(); ) descending.add(it.next()); d.descendingIterator().forEachRemaining( e -> descendingForEachRemaining.add(e)); Collections.reverse(descending); Collections.reverse(descendingForEachRemaining); assertEquals(iterated, descending); assertEquals(iterated, descendingForEachRemaining); } } /** * Iterator.forEachRemaining has same behavior as Iterator's * default implementation. */ public void testForEachRemainingConsistentWithDefaultImplementation() { Collection c = impl.emptyCollection(); if (!testImplementationDetails || c.getClass() == java.util.LinkedList.class) return; ThreadLocalRandom rnd = ThreadLocalRandom.current(); int n = 1 + rnd.nextInt(3); for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); ArrayList iterated = new ArrayList(); ArrayList iteratedForEachRemaining = new ArrayList(); Iterator it1 = c.iterator(); Iterator it2 = c.iterator(); assertTrue(it1.hasNext()); assertTrue(it2.hasNext()); c.clear(); Object r1, r2; try { while (it1.hasNext()) iterated.add(it1.next()); r1 = iterated; } catch (ConcurrentModificationException ex) { r1 = ConcurrentModificationException.class; assertFalse(impl.isConcurrent()); } try { it2.forEachRemaining(iteratedForEachRemaining::add); r2 = iteratedForEachRemaining; } catch (ConcurrentModificationException ex) { r2 = ConcurrentModificationException.class; assertFalse(impl.isConcurrent()); } assertEquals(r1, r2); } /** * Calling Iterator#remove() after Iterator#forEachRemaining * should (maybe) remove last element */ public void testRemoveAfterForEachRemaining() { Collection c = impl.emptyCollection(); ThreadLocalRandom rnd = ThreadLocalRandom.current(); testCollection: { int n = 3 + rnd.nextInt(2); for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); Iterator it = c.iterator(); assertTrue(it.hasNext()); assertEquals(impl.makeElement(0), it.next()); assertTrue(it.hasNext()); assertEquals(impl.makeElement(1), it.next()); it.forEachRemaining(e -> assertTrue(c.contains(e))); if (testImplementationDetails) { if (c instanceof java.util.concurrent.ArrayBlockingQueue) { assertIteratorExhausted(it); } else { try { it.remove(); } catch (UnsupportedOperationException ok) { break testCollection; } assertEquals(n - 1, c.size()); for (int i = 0; i < n - 1; i++) assertTrue(c.contains(impl.makeElement(i))); assertFalse(c.contains(impl.makeElement(n - 1))); } } } if (c instanceof Deque) { Deque d = (Deque) impl.emptyCollection(); int n = 3 + rnd.nextInt(2); for (int i = 0; i < n; i++) d.add(impl.makeElement(i)); Iterator it = d.descendingIterator(); assertTrue(it.hasNext()); assertEquals(impl.makeElement(n - 1), it.next()); assertTrue(it.hasNext()); assertEquals(impl.makeElement(n - 2), it.next()); it.forEachRemaining(e -> assertTrue(c.contains(e))); if (testImplementationDetails) { it.remove(); assertEquals(n - 1, d.size()); for (int i = 1; i < n; i++) assertTrue(d.contains(impl.makeElement(i))); assertFalse(d.contains(impl.makeElement(0))); } } } /** * stream().forEach returns elements in the collection */ public void testStreamForEach() throws Throwable { final Collection c = impl.emptyCollection(); final AtomicLong count = new AtomicLong(0L); final Object x = impl.makeElement(1); final Object y = impl.makeElement(2); final ArrayList found = new ArrayList(); Consumer spy = o -> found.add(o); c.stream().forEach(spy); assertTrue(found.isEmpty()); assertTrue(c.add(x)); c.stream().forEach(spy); assertEquals(Collections.singletonList(x), found); found.clear(); assertTrue(c.add(y)); c.stream().forEach(spy); assertEquals(2, found.size()); assertTrue(found.contains(x)); assertTrue(found.contains(y)); found.clear(); c.clear(); c.stream().forEach(spy); assertTrue(found.isEmpty()); } public void testStreamForEachConcurrentStressTest() throws Throwable { if (!impl.isConcurrent()) return; final Collection c = impl.emptyCollection(); final long testDurationMillis = timeoutMillis(); final AtomicBoolean done = new AtomicBoolean(false); final Object elt = impl.makeElement(1); final Future f1, f2; final ExecutorService pool = Executors.newCachedThreadPool(); try (PoolCleaner cleaner = cleaner(pool, done)) { final CountDownLatch threadsStarted = new CountDownLatch(2); Runnable checkElt = () -> { threadsStarted.countDown(); while (!done.get()) c.stream().forEach(x -> assertSame(x, elt)); }; Runnable addRemove = () -> { threadsStarted.countDown(); while (!done.get()) { assertTrue(c.add(elt)); assertTrue(c.remove(elt)); }}; f1 = pool.submit(checkElt); f2 = pool.submit(addRemove); Thread.sleep(testDurationMillis); } assertNull(f1.get(0L, MILLISECONDS)); assertNull(f2.get(0L, MILLISECONDS)); } /** * collection.forEach returns elements in the collection */ public void testForEach() throws Throwable { final Collection c = impl.emptyCollection(); final AtomicLong count = new AtomicLong(0L); final Object x = impl.makeElement(1); final Object y = impl.makeElement(2); final ArrayList found = new ArrayList(); Consumer spy = o -> found.add(o); c.forEach(spy); assertTrue(found.isEmpty()); assertTrue(c.add(x)); c.forEach(spy); assertEquals(Collections.singletonList(x), found); found.clear(); assertTrue(c.add(y)); c.forEach(spy); assertEquals(2, found.size()); assertTrue(found.contains(x)); assertTrue(found.contains(y)); found.clear(); c.clear(); c.forEach(spy); assertTrue(found.isEmpty()); } /** TODO: promote to a common utility */ static T chooseOne(T ... ts) { return ts[ThreadLocalRandom.current().nextInt(ts.length)]; } /** TODO: more random adders and removers */ static Runnable adderRemover(Collection c, E e) { return chooseOne( () -> { assertTrue(c.add(e)); assertTrue(c.contains(e)); assertTrue(c.remove(e)); assertFalse(c.contains(e)); }, () -> { assertTrue(c.add(e)); assertTrue(c.contains(e)); assertTrue(c.removeIf(x -> x == e)); assertFalse(c.contains(e)); }, () -> { assertTrue(c.add(e)); assertTrue(c.contains(e)); for (Iterator it = c.iterator();; ) if (it.next() == e) { try { it.remove(); } catch (UnsupportedOperationException ok) { c.remove(e); } break; } assertFalse(c.contains(e)); }); } /** * Concurrent Spliterators, once exhausted, stay exhausted. */ public void testStickySpliteratorExhaustion() throws Throwable { if (!impl.isConcurrent()) return; if (!testImplementationDetails) return; final ThreadLocalRandom rnd = ThreadLocalRandom.current(); final Consumer alwaysThrows = e -> { throw new AssertionError(); }; final Collection c = impl.emptyCollection(); final Spliterator s = c.spliterator(); if (rnd.nextBoolean()) { assertFalse(s.tryAdvance(alwaysThrows)); } else { s.forEachRemaining(alwaysThrows); } final Object one = impl.makeElement(1); // Spliterator should not notice added element c.add(one); if (rnd.nextBoolean()) { assertFalse(s.tryAdvance(alwaysThrows)); } else { s.forEachRemaining(alwaysThrows); } } /** * Motley crew of threads concurrently randomly hammer the collection. */ public void testDetectRaces() throws Throwable { if (!impl.isConcurrent()) return; final ThreadLocalRandom rnd = ThreadLocalRandom.current(); final Collection c = impl.emptyCollection(); final long testDurationMillis = expensiveTests ? LONG_DELAY_MS : timeoutMillis(); final AtomicBoolean done = new AtomicBoolean(false); final Object one = impl.makeElement(1); final Object two = impl.makeElement(2); final Consumer checkSanity = x -> assertTrue(x == one || x == two); final Consumer checkArraySanity = array -> { // assertTrue(array.length <= 2); // duplicates are permitted for (Object x : array) assertTrue(x == one || x == two); }; final Object[] emptyArray = (Object[]) java.lang.reflect.Array.newInstance(one.getClass(), 0); final List> futures; final Phaser threadsStarted = new Phaser(1); // register this thread final Runnable[] frobbers = { () -> c.forEach(checkSanity), () -> c.stream().forEach(checkSanity), () -> c.parallelStream().forEach(checkSanity), () -> c.spliterator().trySplit(), () -> { Spliterator s = c.spliterator(); s.tryAdvance(checkSanity); s.trySplit(); }, () -> { Spliterator s = c.spliterator(); do {} while (s.tryAdvance(checkSanity)); }, () -> { for (Object x : c) checkSanity.accept(x); }, () -> checkArraySanity.accept(c.toArray()), () -> checkArraySanity.accept(c.toArray(emptyArray)), () -> { Object[] a = new Object[5]; Object three = impl.makeElement(3); Arrays.fill(a, 0, a.length, three); Object[] x = c.toArray(a); if (x == a) for (int i = 0; i < a.length && a[i] != null; i++) checkSanity.accept(a[i]); // A careful reading of the spec does not support: // for (i++; i < a.length; i++) assertSame(three, a[i]); else checkArraySanity.accept(x); }, adderRemover(c, one), adderRemover(c, two), }; final List tasks = Arrays.stream(frobbers) .filter(task -> rnd.nextBoolean()) // random subset .map(task -> (Runnable) () -> { threadsStarted.arriveAndAwaitAdvance(); while (!done.get()) task.run(); }) .collect(Collectors.toList()); final ExecutorService pool = Executors.newCachedThreadPool(); try (PoolCleaner cleaner = cleaner(pool, done)) { threadsStarted.bulkRegister(tasks.size()); futures = tasks.stream() .map(pool::submit) .collect(Collectors.toList()); threadsStarted.arriveAndDeregister(); Thread.sleep(testDurationMillis); } for (Future future : futures) assertNull(future.get(0L, MILLISECONDS)); } /** * Spliterators are either IMMUTABLE or truly late-binding or, if * concurrent, use the same "late-binding style" of returning * elements added between creation and first use. */ public void testLateBindingStyle() { if (!testImplementationDetails) return; if (impl.klazz() == ArrayList.class) return; // for jdk8 // Immutable (snapshot) spliterators are exempt if (impl.emptyCollection().spliterator() .hasCharacteristics(Spliterator.IMMUTABLE)) return; final Object one = impl.makeElement(1); { final Collection c = impl.emptyCollection(); final Spliterator split = c.spliterator(); c.add(one); assertTrue(split.tryAdvance(e -> { assertSame(e, one); })); assertFalse(split.tryAdvance(e -> { throw new AssertionError(); })); assertTrue(c.contains(one)); } { final AtomicLong count = new AtomicLong(0); final Collection c = impl.emptyCollection(); final Spliterator split = c.spliterator(); c.add(one); split.forEachRemaining( e -> { assertSame(e, one); count.getAndIncrement(); }); assertEquals(1L, count.get()); assertFalse(split.tryAdvance(e -> { throw new AssertionError(); })); assertTrue(c.contains(one)); } } /** * Spliterator.getComparator throws IllegalStateException iff the * spliterator does not report SORTED. */ public void testGetComparator_IllegalStateException() { Collection c = impl.emptyCollection(); Spliterator s = c.spliterator(); boolean reportsSorted = s.hasCharacteristics(Spliterator.SORTED); try { s.getComparator(); assertTrue(reportsSorted); } catch (IllegalStateException ex) { assertFalse(reportsSorted); } } public void testCollectionCopies() throws Exception { ThreadLocalRandom rnd = ThreadLocalRandom.current(); Collection c = impl.emptyCollection(); for (int n = rnd.nextInt(4); n--> 0; ) c.add(impl.makeElement(rnd.nextInt())); assertEquals(c, c); if (c instanceof List) assertCollectionsEquals(c, new ArrayList(c)); else if (c instanceof Set) assertCollectionsEquals(c, new HashSet(c)); else if (c instanceof Deque) assertCollectionsEquivalent(c, new ArrayDeque(c)); Collection clone = cloneableClone(c); if (clone != null) { assertSame(c.getClass(), clone.getClass()); assertCollectionsEquivalent(c, clone); } try { Collection serialClone = serialClonePossiblyFailing(c); assertSame(c.getClass(), serialClone.getClass()); assertCollectionsEquivalent(c, serialClone); } catch (java.io.NotSerializableException acceptable) {} } // public void testCollection8DebugFail() { // fail(impl.klazz().getSimpleName()); // } }