jdk-24/test/jdk/java/util/concurrent/tck/LinkedBlockingQueueTest.java
Martin Buchholz 81e9e6a7fc 8260461: Modernize jsr166 tck tests
Reviewed-by: dl
2021-01-28 18:06:55 +00:00

912 lines
29 KiB
Java

/*
* 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 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/
* Other contributors include Andrew Wright, Jeffrey Hayes,
* Pat Fisher, Mike Judd.
*/
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import junit.framework.Test;
public class LinkedBlockingQueueTest extends JSR166TestCase {
public static class Unbounded extends BlockingQueueTest {
protected BlockingQueue emptyCollection() {
return new LinkedBlockingQueue();
}
}
public static class Bounded extends BlockingQueueTest {
protected BlockingQueue emptyCollection() {
return new LinkedBlockingQueue(SIZE);
}
}
public static void main(String[] args) {
main(suite(), args);
}
public static Test suite() {
class Implementation implements CollectionImplementation {
public Class<?> klazz() { return LinkedBlockingQueue.class; }
public Collection emptyCollection() { return new LinkedBlockingQueue(); }
public Object makeElement(int i) { return JSR166TestCase.itemFor(i); }
public boolean isConcurrent() { return true; }
public boolean permitsNulls() { return false; }
}
return newTestSuite(LinkedBlockingQueueTest.class,
new Unbounded().testSuite(),
new Bounded().testSuite(),
CollectionTest.testSuite(new Implementation()));
}
/**
* Returns a new queue of given size containing consecutive
* Items 0 ... n - 1.
*/
private static LinkedBlockingQueue<Item> populatedQueue(int n) {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(n);
assertTrue(q.isEmpty());
for (int i = 0; i < n; i++)
mustOffer(q, i);
assertFalse(q.isEmpty());
mustEqual(0, q.remainingCapacity());
mustEqual(n, q.size());
mustEqual(0, q.peek());
return q;
}
/**
* A new queue has the indicated capacity, or Integer.MAX_VALUE if
* none given
*/
public void testConstructor1() {
mustEqual(SIZE, new LinkedBlockingQueue<Item>(SIZE).remainingCapacity());
mustEqual(Integer.MAX_VALUE, new LinkedBlockingQueue<Item>().remainingCapacity());
}
/**
* Constructor throws IllegalArgumentException if capacity argument nonpositive
*/
public void testConstructor2() {
try {
new LinkedBlockingQueue<Item>(0);
shouldThrow();
} catch (IllegalArgumentException success) {}
}
/**
* Initializing from null Collection throws NullPointerException
*/
public void testConstructor3() {
try {
new LinkedBlockingQueue<Item>(null);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* Initializing from Collection of null elements throws NullPointerException
*/
public void testConstructor4() {
Collection<Item> elements = Arrays.asList(new Item[SIZE]);
try {
new LinkedBlockingQueue<Item>(elements);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* Initializing from Collection with some null elements throws
* NullPointerException
*/
public void testConstructor5() {
Item[] items = new Item[2];
items[0] = zero;
Collection<Item> elements = Arrays.asList(items);
try {
new LinkedBlockingQueue<Item>(elements);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* Queue contains all elements of collection used to initialize
*/
public void testConstructor6() {
Item[] items = defaultItems;
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(Arrays.asList(items));
for (int i = 0; i < SIZE; ++i)
mustEqual(items[i], q.poll());
}
/**
* Queue transitions from empty to full when elements added
*/
public void testEmptyFull() {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(2);
assertTrue(q.isEmpty());
mustEqual(2, q.remainingCapacity());
q.add(one);
assertFalse(q.isEmpty());
q.add(two);
assertFalse(q.isEmpty());
mustEqual(0, q.remainingCapacity());
assertFalse(q.offer(three));
}
/**
* remainingCapacity decreases on add, increases on remove
*/
public void testRemainingCapacity() {
BlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.remainingCapacity());
mustEqual(SIZE, q.size() + q.remainingCapacity());
mustEqual(i, q.remove());
}
for (int i = 0; i < SIZE; ++i) {
mustEqual(SIZE - i, q.remainingCapacity());
mustEqual(SIZE, q.size() + q.remainingCapacity());
mustAdd(q, i);
}
}
/**
* Offer succeeds if not full; fails if full
*/
public void testOffer() {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(1);
assertTrue(q.offer(zero));
assertFalse(q.offer(one));
}
/**
* add succeeds if not full; throws IllegalStateException if full
*/
public void testAdd() {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(SIZE);
for (int i = 0; i < SIZE; ++i)
mustAdd(q, i);
mustEqual(0, q.remainingCapacity());
try {
q.add(new Item(SIZE));
shouldThrow();
} catch (IllegalStateException success) {}
}
/**
* addAll(this) throws IllegalArgumentException
*/
public void testAddAllSelf() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
try {
q.addAll(q);
shouldThrow();
} catch (IllegalArgumentException success) {}
}
/**
* addAll of a collection with any null elements throws NPE after
* possibly adding some elements
*/
public void testAddAll3() {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(SIZE);
Item[] items = new Item[2]; items[0] = zero;
Collection<Item> elements = Arrays.asList(items);
try {
q.addAll(elements);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* addAll throws IllegalStateException if not enough room
*/
public void testAddAll4() {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(SIZE - 1);
Item[] items = defaultItems;
Collection<Item> elements = Arrays.asList(items);
try {
q.addAll(elements);
shouldThrow();
} catch (IllegalStateException success) {}
}
/**
* Queue contains all elements, in traversal order, of successful addAll
*/
public void testAddAll5() {
Item[] empty = new Item[0];
Item[] items = defaultItems;
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(SIZE);
assertFalse(q.addAll(Arrays.asList(empty)));
assertTrue(q.addAll(Arrays.asList(items)));
for (int i = 0; i < SIZE; ++i)
mustEqual(items[i], q.poll());
}
/**
* all elements successfully put are contained
*/
public void testPut() throws InterruptedException {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(SIZE);
for (int i = 0; i < SIZE; ++i) {
Item x = itemFor(i);
q.put(x);
mustContain(q, x);
}
mustEqual(0, q.remainingCapacity());
}
/**
* put blocks interruptibly if full
*/
public void testBlockingPut() throws InterruptedException {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(SIZE);
final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
for (int i = 0; i < SIZE; ++i)
q.put(itemFor(i));
mustEqual(SIZE, q.size());
mustEqual(0, q.remainingCapacity());
Thread.currentThread().interrupt();
try {
q.put(ninetynine);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
pleaseInterrupt.countDown();
try {
q.put(ninetynine);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseInterrupt);
if (randomBoolean()) assertThreadBlocks(t, Thread.State.WAITING);
t.interrupt();
awaitTermination(t);
mustEqual(SIZE, q.size());
mustEqual(0, q.remainingCapacity());
}
/**
* put blocks interruptibly waiting for take when full
*/
public void testPutWithTake() throws InterruptedException {
final int capacity = 2;
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(2);
final CountDownLatch pleaseTake = new CountDownLatch(1);
final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
for (int i = 0; i < capacity; i++)
q.put(itemFor(i));
pleaseTake.countDown();
q.put(eightysix);
Thread.currentThread().interrupt();
try {
q.put(ninetynine);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
pleaseInterrupt.countDown();
try {
q.put(ninetynine);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseTake);
mustEqual(0, q.remainingCapacity());
mustEqual(0, q.take());
await(pleaseInterrupt);
if (randomBoolean()) assertThreadBlocks(t, Thread.State.WAITING);
t.interrupt();
awaitTermination(t);
mustEqual(0, q.remainingCapacity());
}
/**
* timed offer times out if full and elements not taken
*/
public void testTimedOffer() {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(2);
final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
q.put(zero);
q.put(one);
long startTime = System.nanoTime();
assertFalse(q.offer(two, timeoutMillis(), MILLISECONDS));
assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
Thread.currentThread().interrupt();
try {
q.offer(three, randomTimeout(), randomTimeUnit());
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
pleaseInterrupt.countDown();
try {
q.offer(two, LONGER_DELAY_MS, MILLISECONDS);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseInterrupt);
if (randomBoolean()) assertThreadBlocks(t, Thread.State.TIMED_WAITING);
t.interrupt();
awaitTermination(t);
}
/**
* take retrieves elements in FIFO order
*/
public void testTake() throws InterruptedException {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.take());
}
}
/**
* Take removes existing elements until empty, then blocks interruptibly
*/
public void testBlockingTake() throws InterruptedException {
final BlockingQueue<Item> q = populatedQueue(SIZE);
final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
for (int i = 0; i < SIZE; i++) mustEqual(i, q.take());
Thread.currentThread().interrupt();
try {
q.take();
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
pleaseInterrupt.countDown();
try {
q.take();
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseInterrupt);
if (randomBoolean()) assertThreadBlocks(t, Thread.State.WAITING);
t.interrupt();
awaitTermination(t);
}
/**
* poll succeeds unless empty
*/
public void testPoll() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.poll());
}
assertNull(q.poll());
}
/**
* timed poll with zero timeout succeeds when non-empty, else times out
*/
public void testTimedPoll0() throws InterruptedException {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.poll(0, MILLISECONDS));
}
assertNull(q.poll(0, MILLISECONDS));
}
/**
* timed poll with nonzero timeout succeeds when non-empty, else times out
*/
public void testTimedPoll() throws InterruptedException {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
long startTime = System.nanoTime();
mustEqual(i, q.poll(LONG_DELAY_MS, MILLISECONDS));
assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
}
long startTime = System.nanoTime();
assertNull(q.poll(timeoutMillis(), MILLISECONDS));
assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
checkEmpty(q);
}
/**
* Interrupted timed poll throws InterruptedException instead of
* returning timeout status
*/
public void testInterruptedTimedPoll() throws InterruptedException {
final BlockingQueue<Item> q = populatedQueue(SIZE);
final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
for (int i = 0; i < SIZE; i++)
mustEqual(i, q.poll(LONG_DELAY_MS, MILLISECONDS));
Thread.currentThread().interrupt();
try {
q.poll(randomTimeout(), randomTimeUnit());
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
pleaseInterrupt.countDown();
try {
q.poll(LONGER_DELAY_MS, MILLISECONDS);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseInterrupt);
if (randomBoolean()) assertThreadBlocks(t, Thread.State.TIMED_WAITING);
t.interrupt();
awaitTermination(t);
checkEmpty(q);
}
/**
* peek returns next element, or null if empty
*/
public void testPeek() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.peek());
mustEqual(i, q.poll());
assertTrue(q.peek() == null ||
!q.peek().equals(i));
}
assertNull(q.peek());
}
/**
* element returns next element, or throws NSEE if empty
*/
public void testElement() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.element());
mustEqual(i, q.poll());
}
try {
q.element();
shouldThrow();
} catch (NoSuchElementException success) {}
}
/**
* remove removes next element, or throws NSEE if empty
*/
public void testRemove() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustEqual(i, q.remove());
}
try {
q.remove();
shouldThrow();
} catch (NoSuchElementException success) {}
}
/**
* An add following remove(x) succeeds
*/
public void testRemoveElementAndAdd() throws InterruptedException {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>();
assertTrue(q.add(one));
assertTrue(q.add(two));
mustRemove(q, one);
mustRemove(q, two);
mustAdd(q, three);
assertNotNull(q.take());
}
/**
* contains(x) reports true when elements added but not yet removed
*/
public void testContains() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
mustContain(q, i);
q.poll();
mustNotContain(q, i);
}
}
/**
* clear removes all elements
*/
public void testClear() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
q.clear();
assertTrue(q.isEmpty());
mustEqual(0, q.size());
mustEqual(SIZE, q.remainingCapacity());
q.add(one);
assertFalse(q.isEmpty());
assertTrue(q.contains(one));
q.clear();
assertTrue(q.isEmpty());
}
/**
* containsAll(c) is true when c contains a subset of elements
*/
public void testContainsAll() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
LinkedBlockingQueue<Item> p = new LinkedBlockingQueue<>(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertTrue(q.containsAll(p));
assertFalse(p.containsAll(q));
mustAdd(p, i);
}
assertTrue(p.containsAll(q));
}
/**
* retainAll(c) retains only those elements of c and reports true if changed
*/
public void testRetainAll() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
LinkedBlockingQueue<Item> p = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
boolean changed = q.retainAll(p);
if (i == 0)
assertFalse(changed);
else
assertTrue(changed);
assertTrue(q.containsAll(p));
mustEqual(SIZE - i, q.size());
p.remove();
}
}
/**
* removeAll(c) removes only those elements of c and reports true if changed
*/
public void testRemoveAll() {
for (int i = 1; i < SIZE; ++i) {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
LinkedBlockingQueue<Item> p = populatedQueue(i);
assertTrue(q.removeAll(p));
mustEqual(SIZE - i, q.size());
for (int j = 0; j < i; ++j) {
mustNotContain(q, p.remove());
}
}
}
/**
* toArray contains all elements in FIFO order
*/
public void testToArray() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
Object[] a = q.toArray();
assertSame(Object[].class, a.getClass());
for (Object o : a)
assertSame(o, q.poll());
assertTrue(q.isEmpty());
}
/**
* toArray(a) contains all elements in FIFO order
*/
public void testToArray2() throws InterruptedException {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
Item[] items = new Item[SIZE];
Item[] array = q.toArray(items);
assertSame(items, array);
for (Item o : items)
assertSame(o, q.poll());
assertTrue(q.isEmpty());
}
/**
* toArray(incompatible array type) throws ArrayStoreException
*/
@SuppressWarnings("CollectionToArraySafeParameter")
public void testToArray_incompatibleArrayType() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
try {
q.toArray(new String[10]);
shouldThrow();
} catch (ArrayStoreException success) {}
}
/**
* iterator iterates through all elements
*/
public void testIterator() throws InterruptedException {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
Iterator<? extends Item> it = q.iterator();
int i;
for (i = 0; it.hasNext(); i++)
mustContain(q, it.next());
mustEqual(i, SIZE);
assertIteratorExhausted(it);
it = q.iterator();
for (i = 0; it.hasNext(); i++)
mustEqual(it.next(), q.take());
mustEqual(i, SIZE);
assertIteratorExhausted(it);
}
/**
* iterator of empty collection has no elements
*/
public void testEmptyIterator() {
assertIteratorExhausted(new LinkedBlockingQueue<Item>().iterator());
}
/**
* iterator.remove removes current element
*/
public void testIteratorRemove() {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(3);
q.add(two);
q.add(one);
q.add(three);
Iterator<? extends Item> it = q.iterator();
it.next();
it.remove();
it = q.iterator();
assertSame(it.next(), one);
assertSame(it.next(), three);
assertFalse(it.hasNext());
}
/**
* iterator ordering is FIFO
*/
public void testIteratorOrdering() {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(3);
q.add(one);
q.add(two);
q.add(three);
mustEqual(0, q.remainingCapacity());
int k = 0;
for (Iterator<? extends Item> it = q.iterator(); it.hasNext();) {
mustEqual(++k, it.next());
}
mustEqual(3, k);
}
/**
* Modifications do not cause iterators to fail
*/
public void testWeaklyConsistentIteration() {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(3);
q.add(one);
q.add(two);
q.add(three);
for (Iterator<? extends Item> it = q.iterator(); it.hasNext();) {
q.remove();
it.next();
}
mustEqual(0, q.size());
}
/**
* toString contains toStrings of elements
*/
public void testToString() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
String s = q.toString();
for (int i = 0; i < SIZE; ++i) {
assertTrue(s.contains(String.valueOf(i)));
}
}
/**
* offer transfers elements across Executor tasks
*/
public void testOfferInExecutor() {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(2);
q.add(one);
q.add(two);
final CheckedBarrier threadsStarted = new CheckedBarrier(2);
final ExecutorService executor = Executors.newFixedThreadPool(2);
try (PoolCleaner cleaner = cleaner(executor)) {
executor.execute(new CheckedRunnable() {
public void realRun() throws InterruptedException {
assertFalse(q.offer(three));
threadsStarted.await();
assertTrue(q.offer(three, LONG_DELAY_MS, MILLISECONDS));
mustEqual(0, q.remainingCapacity());
}});
executor.execute(new CheckedRunnable() {
public void realRun() throws InterruptedException {
threadsStarted.await();
assertSame(one, q.take());
}});
}
}
/**
* timed poll retrieves elements across Executor threads
*/
public void testPollInExecutor() {
final LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>(2);
final CheckedBarrier threadsStarted = new CheckedBarrier(2);
final ExecutorService executor = Executors.newFixedThreadPool(2);
try (PoolCleaner cleaner = cleaner(executor)) {
executor.execute(new CheckedRunnable() {
public void realRun() throws InterruptedException {
assertNull(q.poll());
threadsStarted.await();
assertSame(one, q.poll(LONG_DELAY_MS, MILLISECONDS));
checkEmpty(q);
}});
executor.execute(new CheckedRunnable() {
public void realRun() throws InterruptedException {
threadsStarted.await();
q.put(one);
}});
}
}
/**
* A deserialized/reserialized queue has same elements in same order
*/
public void testSerialization() throws Exception {
Queue<Item> x = populatedQueue(SIZE);
Queue<Item> y = serialClone(x);
assertNotSame(x, y);
mustEqual(x.size(), y.size());
mustEqual(x.toString(), y.toString());
assertTrue(Arrays.equals(x.toArray(), y.toArray()));
while (!x.isEmpty()) {
assertFalse(y.isEmpty());
mustEqual(x.remove(), y.remove());
}
assertTrue(y.isEmpty());
}
/**
* drainTo(c) empties queue into another collection c
*/
public void testDrainTo() {
LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
ArrayList<Item> l = new ArrayList<>();
q.drainTo(l);
mustEqual(0, q.size());
mustEqual(SIZE, l.size());
for (int i = 0; i < SIZE; ++i)
mustEqual(l.get(i), i);
q.add(zero);
q.add(one);
assertFalse(q.isEmpty());
mustContain(q, zero);
mustContain(q, one);
l.clear();
q.drainTo(l);
mustEqual(0, q.size());
mustEqual(2, l.size());
for (int i = 0; i < 2; ++i)
mustEqual(l.get(i), i);
}
/**
* drainTo empties full queue, unblocking a waiting put.
*/
public void testDrainToWithActivePut() throws InterruptedException {
final LinkedBlockingQueue<Item> q = populatedQueue(SIZE);
Thread t = new Thread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
q.put(new Item(SIZE + 1));
}});
t.start();
ArrayList<Item> l = new ArrayList<>();
q.drainTo(l);
assertTrue(l.size() >= SIZE);
for (int i = 0; i < SIZE; ++i)
mustEqual(l.get(i), i);
t.join();
assertTrue(q.size() + l.size() >= SIZE);
}
/**
* drainTo(c, n) empties first min(n, size) elements of queue into c
*/
public void testDrainToN() {
LinkedBlockingQueue<Item> q = new LinkedBlockingQueue<>();
for (int i = 0; i < SIZE + 2; ++i) {
for (int j = 0; j < SIZE; j++)
mustOffer(q, j);
ArrayList<Item> l = new ArrayList<>();
q.drainTo(l, i);
int k = (i < SIZE) ? i : SIZE;
mustEqual(k, l.size());
mustEqual(SIZE - k, q.size());
for (int j = 0; j < k; ++j)
mustEqual(l.get(j), j);
do {} while (q.poll() != null);
}
}
/**
* remove(null), contains(null) always return false
*/
public void testNeverContainsNull() {
Collection<?>[] qs = {
new LinkedBlockingQueue<>(),
populatedQueue(2),
};
for (Collection<?> q : qs) {
assertFalse(q.contains(null));
assertFalse(q.remove(null));
}
}
}