/*
* 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.
*/
package jsr166;
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 {
// android-note: These tests have been moved into their own separate
// classes to work around CTS issues.
//
// 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() {
// return newTestSuite(LinkedBlockingQueueTest.class,
// new Unbounded().testSuite(),
// new Bounded().testSuite());
// }
/**
* Returns a new queue of given size containing consecutive
* Integers 0 ... n.
*/
private LinkedBlockingQueue<Integer> populatedQueue(int n) {
LinkedBlockingQueue<Integer> q =
new LinkedBlockingQueue<Integer>(n);
assertTrue(q.isEmpty());
for (int i = 0; i < n; i++)
assertTrue(q.offer(new Integer(i)));
assertFalse(q.isEmpty());
assertEquals(0, q.remainingCapacity());
assertEquals(n, q.size());
return q;
}
/**
* A new queue has the indicated capacity, or Integer.MAX_VALUE if
* none given
*/
public void testConstructor1() {
assertEquals(SIZE, new LinkedBlockingQueue(SIZE).remainingCapacity());
assertEquals(Integer.MAX_VALUE, new LinkedBlockingQueue().remainingCapacity());
}
/**
* Constructor throws IllegalArgumentException if capacity argument nonpositive
*/
public void testConstructor2() {
try {
new LinkedBlockingQueue(0);
shouldThrow();
} catch (IllegalArgumentException success) {}
}
/**
* Initializing from null Collection throws NullPointerException
*/
public void testConstructor3() {
try {
new LinkedBlockingQueue(null);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* Initializing from Collection of null elements throws NullPointerException
*/
public void testConstructor4() {
Collection<Integer> elements = Arrays.asList(new Integer[SIZE]);
try {
new LinkedBlockingQueue(elements);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* Initializing from Collection with some null elements throws
* NullPointerException
*/
public void testConstructor5() {
Integer[] ints = new Integer[SIZE];
for (int i = 0; i < SIZE-1; ++i)
ints[i] = new Integer(i);
Collection<Integer> elements = Arrays.asList(ints);
try {
new LinkedBlockingQueue(elements);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* Queue contains all elements of collection used to initialize
*/
public void testConstructor6() {
Integer[] ints = new Integer[SIZE];
for (int i = 0; i < SIZE; ++i)
ints[i] = new Integer(i);
LinkedBlockingQueue q = new LinkedBlockingQueue(Arrays.asList(ints));
for (int i = 0; i < SIZE; ++i)
assertEquals(ints[i], q.poll());
}
/**
* Queue transitions from empty to full when elements added
*/
public void testEmptyFull() {
LinkedBlockingQueue q = new LinkedBlockingQueue(2);
assertTrue(q.isEmpty());
assertEquals("should have room for 2", 2, q.remainingCapacity());
q.add(one);
assertFalse(q.isEmpty());
q.add(two);
assertFalse(q.isEmpty());
assertEquals(0, q.remainingCapacity());
assertFalse(q.offer(three));
}
/**
* remainingCapacity decreases on add, increases on remove
*/
public void testRemainingCapacity() {
BlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(i, q.remainingCapacity());
assertEquals(SIZE, q.size() + q.remainingCapacity());
assertEquals(i, q.remove());
}
for (int i = 0; i < SIZE; ++i) {
assertEquals(SIZE-i, q.remainingCapacity());
assertEquals(SIZE, q.size() + q.remainingCapacity());
assertTrue(q.add(i));
}
}
/**
* Offer succeeds if not full; fails if full
*/
public void testOffer() {
LinkedBlockingQueue 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 q = new LinkedBlockingQueue(SIZE);
for (int i = 0; i < SIZE; ++i)
assertTrue(q.add(new Integer(i)));
assertEquals(0, q.remainingCapacity());
try {
q.add(new Integer(SIZE));
shouldThrow();
} catch (IllegalStateException success) {}
}
/**
* addAll(this) throws IllegalArgumentException
*/
public void testAddAllSelf() {
LinkedBlockingQueue 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 q = new LinkedBlockingQueue(SIZE);
Integer[] ints = new Integer[SIZE];
for (int i = 0; i < SIZE-1; ++i)
ints[i] = new Integer(i);
Collection<Integer> elements = Arrays.asList(ints);
try {
q.addAll(elements);
shouldThrow();
} catch (NullPointerException success) {}
}
/**
* addAll throws IllegalStateException if not enough room
*/
public void testAddAll4() {
LinkedBlockingQueue q = new LinkedBlockingQueue(SIZE - 1);
Integer[] ints = new Integer[SIZE];
for (int i = 0; i < SIZE; ++i)
ints[i] = new Integer(i);
Collection<Integer> elements = Arrays.asList(ints);
try {
q.addAll(elements);
shouldThrow();
} catch (IllegalStateException success) {}
}
/**
* Queue contains all elements, in traversal order, of successful addAll
*/
public void testAddAll5() {
Integer[] empty = new Integer[0];
Integer[] ints = new Integer[SIZE];
for (int i = 0; i < SIZE; ++i)
ints[i] = new Integer(i);
LinkedBlockingQueue q = new LinkedBlockingQueue(SIZE);
assertFalse(q.addAll(Arrays.asList(empty)));
assertTrue(q.addAll(Arrays.asList(ints)));
for (int i = 0; i < SIZE; ++i)
assertEquals(ints[i], q.poll());
}
/**
* all elements successfully put are contained
*/
public void testPut() throws InterruptedException {
LinkedBlockingQueue q = new LinkedBlockingQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
Integer x = new Integer(i);
q.put(x);
assertTrue(q.contains(x));
}
assertEquals(0, q.remainingCapacity());
}
/**
* put blocks interruptibly if full
*/
public void testBlockingPut() throws InterruptedException {
final LinkedBlockingQueue 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(i);
assertEquals(SIZE, q.size());
assertEquals(0, q.remainingCapacity());
Thread.currentThread().interrupt();
try {
q.put(99);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
pleaseInterrupt.countDown();
try {
q.put(99);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseInterrupt);
assertThreadStaysAlive(t);
t.interrupt();
awaitTermination(t);
assertEquals(SIZE, q.size());
assertEquals(0, q.remainingCapacity());
}
/**
* put blocks interruptibly waiting for take when full
*/
public void testPutWithTake() throws InterruptedException {
final int capacity = 2;
final LinkedBlockingQueue 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(i);
pleaseTake.countDown();
q.put(86);
pleaseInterrupt.countDown();
try {
q.put(99);
shouldThrow();
} catch (InterruptedException success) {}
assertFalse(Thread.interrupted());
}});
await(pleaseTake);
assertEquals(0, q.remainingCapacity());
assertEquals(0, q.take());
await(pleaseInterrupt);
assertThreadStaysAlive(t);
t.interrupt();
awaitTermination(t);
assertEquals(0, q.remainingCapacity());
}
/**
* timed offer times out if full and elements not taken
*/
public void testTimedOffer() {
final LinkedBlockingQueue q = new LinkedBlockingQueue(2);
final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
q.put(new Object());
q.put(new Object());
long startTime = System.nanoTime();
assertFalse(q.offer(new Object(), timeoutMillis(), MILLISECONDS));
assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
pleaseInterrupt.countDown();
try {
q.offer(new Object(), 2 * LONG_DELAY_MS, MILLISECONDS);
shouldThrow();
} catch (InterruptedException success) {}
}});
await(pleaseInterrupt);
assertThreadStaysAlive(t);
t.interrupt();
awaitTermination(t);
}
/**
* take retrieves elements in FIFO order
*/
public void testTake() throws InterruptedException {
LinkedBlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(i, q.take());
}
}
/**
* Take removes existing elements until empty, then blocks interruptibly
*/
public void testBlockingTake() throws InterruptedException {
final BlockingQueue 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) {
assertEquals(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);
assertThreadStaysAlive(t);
t.interrupt();
awaitTermination(t);
}
/**
* poll succeeds unless empty
*/
public void testPoll() {
LinkedBlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(i, q.poll());
}
assertNull(q.poll());
}
/**
* timed poll with zero timeout succeeds when non-empty, else times out
*/
public void testTimedPoll0() throws InterruptedException {
LinkedBlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(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<Integer> q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
long startTime = System.nanoTime();
assertEquals(i, (int) 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<Integer> q = populatedQueue(SIZE);
final CountDownLatch aboutToWait = new CountDownLatch(1);
Thread t = newStartedThread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
for (int i = 0; i < SIZE; ++i) {
long t0 = System.nanoTime();
assertEquals(i, (int) q.poll(LONG_DELAY_MS, MILLISECONDS));
assertTrue(millisElapsedSince(t0) < SMALL_DELAY_MS);
}
long t0 = System.nanoTime();
aboutToWait.countDown();
try {
q.poll(MEDIUM_DELAY_MS, MILLISECONDS);
shouldThrow();
} catch (InterruptedException success) {
assertTrue(millisElapsedSince(t0) < MEDIUM_DELAY_MS);
}
}});
aboutToWait.await();
waitForThreadToEnterWaitState(t, SMALL_DELAY_MS);
t.interrupt();
awaitTermination(t, MEDIUM_DELAY_MS);
checkEmpty(q);
}
/**
* peek returns next element, or null if empty
*/
public void testPeek() {
LinkedBlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(i, q.peek());
assertEquals(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 q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(i, q.element());
assertEquals(i, q.poll());
}
try {
q.element();
shouldThrow();
} catch (NoSuchElementException success) {}
}
/**
* remove removes next element, or throws NSEE if empty
*/
public void testRemove() {
LinkedBlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(i, q.remove());
}
try {
q.remove();
shouldThrow();
} catch (NoSuchElementException success) {}
}
/**
* An add following remove(x) succeeds
*/
public void testRemoveElementAndAdd() throws InterruptedException {
LinkedBlockingQueue q = new LinkedBlockingQueue();
assertTrue(q.add(new Integer(1)));
assertTrue(q.add(new Integer(2)));
assertTrue(q.remove(new Integer(1)));
assertTrue(q.remove(new Integer(2)));
assertTrue(q.add(new Integer(3)));
assertNotNull(q.take());
}
/**
* contains(x) reports true when elements added but not yet removed
*/
public void testContains() {
LinkedBlockingQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertTrue(q.contains(new Integer(i)));
q.poll();
assertFalse(q.contains(new Integer(i)));
}
}
/**
* clear removes all elements
*/
public void testClear() {
LinkedBlockingQueue q = populatedQueue(SIZE);
q.clear();
assertTrue(q.isEmpty());
assertEquals(0, q.size());
assertEquals(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 q = populatedQueue(SIZE);
LinkedBlockingQueue p = new LinkedBlockingQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertTrue(q.containsAll(p));
assertFalse(p.containsAll(q));
p.add(new Integer(i));
}
assertTrue(p.containsAll(q));
}
/**
* retainAll(c) retains only those elements of c and reports true if changed
*/
public void testRetainAll() {
LinkedBlockingQueue q = populatedQueue(SIZE);
LinkedBlockingQueue 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));
assertEquals(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 q = populatedQueue(SIZE);
LinkedBlockingQueue p = populatedQueue(i);
assertTrue(q.removeAll(p));
assertEquals(SIZE-i, q.size());
for (int j = 0; j < i; ++j) {
Integer x = (Integer)(p.remove());
assertFalse(q.contains(x));
}
}
}
/**
* toArray contains all elements in FIFO order
*/
public void testToArray() {
LinkedBlockingQueue q = populatedQueue(SIZE);
Object[] o = q.toArray();
for (int i = 0; i < o.length; i++)
assertSame(o[i], q.poll());
}
/**
* toArray(a) contains all elements in FIFO order
*/
public void testToArray2() throws InterruptedException {
LinkedBlockingQueue<Integer> q = populatedQueue(SIZE);
Integer[] ints = new Integer[SIZE];
Integer[] array = q.toArray(ints);
assertSame(ints, array);
for (int i = 0; i < ints.length; i++)
assertSame(ints[i], q.poll());
}
/**
* toArray(incompatible array type) throws ArrayStoreException
*/
public void testToArray1_BadArg() {
LinkedBlockingQueue q = populatedQueue(SIZE);
try {
q.toArray(new String[10]);
shouldThrow();
} catch (ArrayStoreException success) {}
}
/**
* iterator iterates through all elements
*/
public void testIterator() throws InterruptedException {
LinkedBlockingQueue q = populatedQueue(SIZE);
Iterator it = q.iterator();
int i;
for (i = 0; it.hasNext(); i++)
assertTrue(q.contains(it.next()));
assertEquals(i, SIZE);
assertIteratorExhausted(it);
it = q.iterator();
for (i = 0; it.hasNext(); i++)
assertEquals(it.next(), q.take());
assertEquals(i, SIZE);
assertIteratorExhausted(it);
}
/**
* iterator of empty collection has no elements
*/
public void testEmptyIterator() {
assertIteratorExhausted(new LinkedBlockingQueue().iterator());
}
/**
* iterator.remove removes current element
*/
public void testIteratorRemove() {
final LinkedBlockingQueue q = new LinkedBlockingQueue(3);
q.add(two);
q.add(one);
q.add(three);
Iterator 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 q = new LinkedBlockingQueue(3);
q.add(one);
q.add(two);
q.add(three);
assertEquals(0, q.remainingCapacity());
int k = 0;
for (Iterator it = q.iterator(); it.hasNext();) {
assertEquals(++k, it.next());
}
assertEquals(3, k);
}
/**
* Modifications do not cause iterators to fail
*/
public void testWeaklyConsistentIteration() {
final LinkedBlockingQueue q = new LinkedBlockingQueue(3);
q.add(one);
q.add(two);
q.add(three);
for (Iterator it = q.iterator(); it.hasNext();) {
q.remove();
it.next();
}
assertEquals(0, q.size());
}
/**
* toString contains toStrings of elements
*/
public void testToString() {
LinkedBlockingQueue 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 q = new LinkedBlockingQueue(2);
q.add(one);
q.add(two);
ExecutorService executor = Executors.newFixedThreadPool(2);
final CheckedBarrier threadsStarted = new CheckedBarrier(2);
executor.execute(new CheckedRunnable() {
public void realRun() throws InterruptedException {
assertFalse(q.offer(three));
threadsStarted.await();
assertTrue(q.offer(three, LONG_DELAY_MS, MILLISECONDS));
assertEquals(0, q.remainingCapacity());
}});
executor.execute(new CheckedRunnable() {
public void realRun() throws InterruptedException {
threadsStarted.await();
assertSame(one, q.take());
}});
joinPool(executor);
}
/**
* timed poll retrieves elements across Executor threads
*/
public void testPollInExecutor() {
final LinkedBlockingQueue q = new LinkedBlockingQueue(2);
final CheckedBarrier threadsStarted = new CheckedBarrier(2);
ExecutorService executor = Executors.newFixedThreadPool(2);
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);
}});
joinPool(executor);
}
/**
* A deserialized serialized queue has same elements in same order
*/
public void testSerialization() throws Exception {
Queue x = populatedQueue(SIZE);
Queue y = serialClone(x);
assertNotSame(x, y);
assertEquals(x.size(), y.size());
assertEquals(x.toString(), y.toString());
assertTrue(Arrays.equals(x.toArray(), y.toArray()));
while (!x.isEmpty()) {
assertFalse(y.isEmpty());
assertEquals(x.remove(), y.remove());
}
assertTrue(y.isEmpty());
}
/**
* drainTo(c) empties queue into another collection c
*/
public void testDrainTo() {
LinkedBlockingQueue q = populatedQueue(SIZE);
ArrayList l = new ArrayList();
q.drainTo(l);
assertEquals(0, q.size());
assertEquals(SIZE, l.size());
for (int i = 0; i < SIZE; ++i)
assertEquals(l.get(i), new Integer(i));
q.add(zero);
q.add(one);
assertFalse(q.isEmpty());
assertTrue(q.contains(zero));
assertTrue(q.contains(one));
l.clear();
q.drainTo(l);
assertEquals(0, q.size());
assertEquals(2, l.size());
for (int i = 0; i < 2; ++i)
assertEquals(l.get(i), new Integer(i));
}
/**
* drainTo empties full queue, unblocking a waiting put.
*/
public void testDrainToWithActivePut() throws InterruptedException {
final LinkedBlockingQueue q = populatedQueue(SIZE);
Thread t = new Thread(new CheckedRunnable() {
public void realRun() throws InterruptedException {
q.put(new Integer(SIZE+1));
}});
t.start();
ArrayList l = new ArrayList();
q.drainTo(l);
assertTrue(l.size() >= SIZE);
for (int i = 0; i < SIZE; ++i)
assertEquals(l.get(i), new Integer(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 q = new LinkedBlockingQueue();
for (int i = 0; i < SIZE + 2; ++i) {
for (int j = 0; j < SIZE; j++)
assertTrue(q.offer(new Integer(j)));
ArrayList l = new ArrayList();
q.drainTo(l, i);
int k = (i < SIZE) ? i : SIZE;
assertEquals(k, l.size());
assertEquals(SIZE-k, q.size());
for (int j = 0; j < k; ++j)
assertEquals(l.get(j), new Integer(j));
do {} while (q.poll() != null);
}
}
/**
* remove(null), contains(null) always return false
*/
public void testNeverContainsNull() {
Collection<?>[] qs = {
new LinkedBlockingQueue<Object>(),
populatedQueue(2),
};
for (Collection<?> q : qs) {
assertFalse(q.contains(null));
assertFalse(q.remove(null));
}
}
}