java.util.concurrent.atomic.AtomicIntegerFieldUpdater Java Examples

/**
 * Offer {@code item} to the queue, try to acquire the processing lock, and if successful return an item for
 * single-consumer style processing. If non-{@code null} is returned the caller is responsible for releasing
 * the lock!
 * @param queue The {@link Queue#offer(Object)} and {@link Queue#poll()} (assuming lock was acquired).
 * @param lockUpdater Used to acquire the lock via
 * {@link ConcurrentUtils#tryAcquireLock(AtomicIntegerFieldUpdater, Object)}.
 * @param item The item to {@link Queue#offer(Object)}.
 * @param <T> The type of item in the {@link Queue}.
 * @return {@code null} if the queue was empty, or the lock couldn't be acquired. otherwise the lock has been
 * acquired and it is the caller's responsibility to release!
 */
@Nullable
private <T> T addAndTryPoll(final Queue<T> queue,
    @SuppressWarnings("rawtypes") final AtomicIntegerFieldUpdater<NettyPipelinedConnection> lockUpdater, T item) {
    queue.add(item);
    while (tryAcquireLock(lockUpdater, this)) {
        // exceptions are not expected from poll, and if they occur we can't reliably recover which would involve
        // draining the queue. just throw with the lock poisoned, callers will propagate the exception to related
        // subscriber and close the connection.
        final T next = queue.poll();
        if (next != null) {
            return next; // lock must be released when the returned task completes!
        } else if (releaseLock(lockUpdater, this)) {
            return null;
        }
    }
    return null;
}
 

/**
 * Poll the {@code queue} and attempt to process an item. The lock must be acquired on entry into this method and
 * if this method return non-{@code null} the lock will not be released (caller's responsibility to later release)
 * to continue the single-consumer style processing.
 * @param queue The queue to {@link Queue#poll()}.
 * @param lockUpdater Used to release via
 * {@link ConcurrentUtils#releaseLock(AtomicIntegerFieldUpdater, Object)} if the queue is empty
 * @param <T> The type of item in the {@link Queue}.
 * @return {@code null} if the queue was empty. otherwise the lock remains acquired and it is the caller's
 * responsibility to release (via subsequent calls to this method).
 */
@Nullable
private <T> T pollWithLockAcquired(final Queue<T> queue,
           @SuppressWarnings("rawtypes") final AtomicIntegerFieldUpdater<NettyPipelinedConnection> lockUpdater) {
    // the lock has been acquired!
    try {
        do {
            final T next = queue.poll();
            if (next != null) {
                return next; // lock must be released when the returned task completes!
            } else if (releaseLock(lockUpdater, this)) {
                return null;
            }
        } while (tryAcquireLock(lockUpdater, this));

        return null;
    } catch (Throwable cause) {
        // exceptions are not expected from poll, and if they occur we can't reliably recover which would involve
        // draining the queue. just throw with the lock poisoned and close the connection.
        connection.closeAsync().subscribe();
        throw cause;
    }
}
 

/**
 * compareAndSet in one thread enables another waiting for value
 * to succeed
 */
public void testCompareAndSetInMultipleThreads() throws Exception {
    x = 1;
    final AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");

    Thread t = new Thread(new CheckedRunnable() {
        public void realRun() {
            while (!a.compareAndSet(AtomicIntegerFieldUpdaterTest.this, 2, 3))
                Thread.yield();
        }});

    t.start();
    assertTrue(a.compareAndSet(this, 1, 2));
    t.join(LONG_DELAY_MS);
    assertFalse(t.isAlive());
    assertEquals(3, a.get(this));
}
 

/**
 * compareAndSet in one thread enables another waiting for value
 * to succeed
 */
public void testCompareAndSetInMultipleThreads() throws Exception {
    x = 1;
    final AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");

    Thread t = new Thread(new CheckedRunnable() {
        public void realRun() {
            while (!a.compareAndSet(AtomicIntegerFieldUpdaterTest.this, 2, 3))
                Thread.yield();
        }});

    t.start();
    assertTrue(a.compareAndSet(this, 1, 2));
    t.join(LONG_DELAY_MS);
    assertFalse(t.isAlive());
    assertEquals(3, a.get(this));
}
 

/**
 * getAndAdd returns previous value and adds given value
 */
public void testGetAndAdd() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.getAndAdd(this, 2));
    assertEquals(3, a.get(this));
    assertEquals(3, a.getAndAdd(this, -4));
    assertEquals(-1, a.get(this));
}
 

/**
 * get returns the last value lazySet by same thread
 */
public void testGetLazySet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.get(this));
    a.lazySet(this, 2);
    assertEquals(2, a.get(this));
    a.lazySet(this, -3);
    assertEquals(-3, a.get(this));
}
 

/**
 * get returns the last value set or assigned
 */
public void testGetSet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.get(this));
    a.set(this, 2);
    assertEquals(2, a.get(this));
    a.set(this, -3);
    assertEquals(-3, a.get(this));
}
 

/**
 * compareAndSet succeeds in changing value if equal to expected else fails
 */
public void testCompareAndSet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertTrue(a.compareAndSet(this, 1, 2));
    assertTrue(a.compareAndSet(this, 2, -4));
    assertEquals(-4, a.get(this));
    assertFalse(a.compareAndSet(this, -5, 7));
    assertEquals(-4, a.get(this));
    assertTrue(a.compareAndSet(this, -4, 7));
    assertEquals(7, a.get(this));
}
 

/**
 * AtomicIntegerFieldUpdater accumulateAndGet updates with supplied
 * function and returns result.
 */
public void testIntegerFieldUpdaterAccumulateAndGet() {
    AtomicIntegerFieldUpdater a = anIntFieldUpdater();
    a.set(this, 1);
    assertEquals(7, a.accumulateAndGet(this, 6, Integer::sum));
    assertEquals(10, a.accumulateAndGet(this, 3, Integer::sum));
    assertEquals(10, a.get(this));
    assertEquals(10, anIntField);
}
 

/**
 * AtomicIntegerFieldUpdater getAndAccumulate returns previous value
 * and updates with supplied function.
 */
public void testIntegerFieldUpdaterGetAndAccumulate() {
    AtomicIntegerFieldUpdater a = anIntFieldUpdater();
    a.set(this, 1);
    assertEquals(1, a.getAndAccumulate(this, 2, Integer::sum));
    assertEquals(3, a.getAndAccumulate(this, 3, Integer::sum));
    assertEquals(6, a.get(this));
    assertEquals(6, anIntField);
}
 

/**
 * AtomicIntegerFieldUpdater updateAndGet updates with supplied function and
 * returns result.
 */
public void testIntegerFieldUpdaterUpdateAndGet() {
    AtomicIntegerFieldUpdater a = anIntFieldUpdater();
    a.set(this, 1);
    assertEquals(18, a.updateAndGet(this, Atomic8Test::addInt17));
    assertEquals(35, a.updateAndGet(this, Atomic8Test::addInt17));
    assertEquals(35, a.get(this));
    assertEquals(35, anIntField);
}
 

/**
 * Create a new optimized {@link AtomicIntegerFieldUpdater} or {@code null} if it
 * could not be created. Because of this the caller need to check for {@code null} and if {@code null} is returned
 * use {@link AtomicIntegerFieldUpdater#newUpdater(Class, String)} as fallback.
 */
public static <T> AtomicIntegerFieldUpdater<T> newAtomicIntegerFieldUpdater(
        Class<?> tclass, String fieldName) {
    if (hasUnsafe()) {
        try {
            return PlatformDependent0.newAtomicIntegerFieldUpdater(tclass, fieldName);
        } catch (Throwable ignore) {
            // ignore
        }
    }
    return null;
}
 

/**
 * repeated weakCompareAndSet succeeds in changing value when equal
 * to expected
 */
public void testWeakCompareAndSet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    do {} while (!a.weakCompareAndSet(this, 1, 2));
    do {} while (!a.weakCompareAndSet(this, 2, -4));
    assertEquals(-4, a.get(this));
    do {} while (!a.weakCompareAndSet(this, -4, 7));
    assertEquals(7, a.get(this));
}
 

/**
 * Creates and returns an updater for objects with the given integer field.
 */
public static <T> AtomicIntegerFieldUpdater<T> newIntegerFieldUpdater(
    Class<T> tclass, String fieldName) {
  if (UnsafeHolder.hasUnsafe()) {
    return new UnsafeAtomicIntegerFieldUpdater<T>(tclass, fieldName);
  }
  else {
    return AtomicIntegerFieldUpdater.newUpdater(tclass, fieldName);
  }
}
 

@SuppressWarnings("unchecked")
private Consumer getNextConsumer(PersistentDispatcherMultipleConsumers dispatcher) throws Exception {

    Consumer consumer = dispatcher.getNextConsumer();

    if (consumer != null) {
        Field field = Consumer.class.getDeclaredField("MESSAGE_PERMITS_UPDATER");
        field.setAccessible(true);
        AtomicIntegerFieldUpdater<Consumer> messagePermits = (AtomicIntegerFieldUpdater<Consumer>) field.get(consumer);
        messagePermits.decrementAndGet(consumer);
        return consumer;
    }
    return null;
}
 

public void reset() {
    this.maxRequestTimeUpdater = AtomicIntegerFieldUpdater.newUpdater(Metrics.class, "maxRequestTime");
    this.minRequestTimeUpdater = AtomicIntegerFieldUpdater.newUpdater(Metrics.class, "minRequestTime");
    this.totalRequestTimeUpdater = AtomicLongFieldUpdater.newUpdater(Metrics.class, "totalRequestTime");
    this.totalRequestsUpdater = AtomicLongFieldUpdater.newUpdater(Metrics.class, "totalRequests");
    this.responseCount = new ConcurrentHashMap<>(INITIAL_CAPACITY, LOAD_FACTOR, CONCURRENCY_LEVEL);
    this.dataSend = new AtomicLong();
    this.avgRequestTime = 0;
    this.totalRequestTime = 0;
    this.totalRequests = 0;
    this.maxRequestTime = -1;
    this.minRequestTime = -1;
}
 

/**
 * compareAndSet succeeds in changing protected field value if
 * equal to expected else fails
 */
public void testCompareAndSetProtected() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("protectedField");
    protectedField = 1;
    assertTrue(a.compareAndSet(this, 1, 2));
    assertTrue(a.compareAndSet(this, 2, -4));
    assertEquals(-4, a.get(this));
    assertFalse(a.compareAndSet(this, -5, 7));
    assertEquals(-4, a.get(this));
    assertTrue(a.compareAndSet(this, -4, 7));
    assertEquals(7, a.get(this));
}
 

/**
 * AtomicIntegerFieldUpdater getAndUpdate returns previous value and updates
 * result of supplied function
 */
public void testIntegerFieldUpdaterGetAndUpdate() {
    AtomicIntegerFieldUpdater a = anIntFieldUpdater();
    a.set(this, 1);
    assertEquals(1, a.getAndUpdate(this, Atomic8Test::addInt17));
    assertEquals(18, a.getAndUpdate(this, Atomic8Test::addInt17));
    assertEquals(35, a.get(this));
    assertEquals(35, anIntField);
}
 

/**
 * Ensure that the load manager's zookeeper data cache is shutdown after invoking stop().
 */
@Test
public void testStop() throws Exception {
    final SimpleLoadManagerImpl loadManager = (SimpleLoadManagerImpl) pulsarServices[0].getLoadManager().get();
    loadManager.stop();
    Field loadReportCacheField = SimpleLoadManagerImpl.class.getDeclaredField("loadReportCacheZk");
    loadReportCacheField.setAccessible(true);
    ZooKeeperDataCache<LoadReport> loadReportCache = (ZooKeeperDataCache<LoadReport>) loadReportCacheField
            .get(loadManager);
    Field IS_SHUTDOWN_UPDATER = ZooKeeperDataCache.class.getDeclaredField("IS_SHUTDOWN_UPDATER");
    IS_SHUTDOWN_UPDATER.setAccessible(true);
    final int TRUE = 1;
    assert (((AtomicIntegerFieldUpdater<ZooKeeperDataCache>) (IS_SHUTDOWN_UPDATER.get(loadReportCache))).get(loadReportCache) == TRUE);
}
 

/** compare raw numbers for atomic ops using JDK vs unsafe wrapper classes */
public void SW_testCompareAtomicOps() {

  final AtomicIntegerFieldUpdater<ConcurrentMapOpsTest> intJDKCounter =
      AtomicIntegerFieldUpdater.newUpdater(ConcurrentMapOpsTest.class,
          "intJDKCounter");
  final AtomicLongFieldUpdater<ConcurrentMapOpsTest> longJDKCounter =
      AtomicLongFieldUpdater.newUpdater(ConcurrentMapOpsTest.class,
          "longJDKCounter");
  final AtomicReferenceFieldUpdater<ConcurrentMapOpsTest, LongRef>
      refJDKCounter = AtomicReferenceFieldUpdater.newUpdater(
          ConcurrentMapOpsTest.class, LongRef.class, "refJDKCounter");

  final AtomicIntegerFieldUpdater<ConcurrentMapOpsTest> intUnsafeCounter =
      AtomicUpdaterFactory.newIntegerFieldUpdater(ConcurrentMapOpsTest.class,
          "intUnsafeCounter");
  final AtomicLongFieldUpdater<ConcurrentMapOpsTest> longUnsafeCounter =
      AtomicUpdaterFactory.newLongFieldUpdater(ConcurrentMapOpsTest.class,
          "longUnsafeCounter");
  final AtomicReferenceFieldUpdater<ConcurrentMapOpsTest, LongRef>
      refUnsafeCounter = AtomicUpdaterFactory.newReferenceFieldUpdater(
          ConcurrentMapOpsTest.class, LongRef.class, "refUnsafeCounter");

  // some warmups
  runAtomicOps(1, 50000, intJDKCounter, longJDKCounter, refJDKCounter,
      intUnsafeCounter, longUnsafeCounter, refUnsafeCounter);

  // timed runs with single threads to see the raw overheads with no
  // concurrency (as we would expect in most usual cases)
  runAtomicOps(1, 50000000, intJDKCounter, longJDKCounter, refJDKCounter,
      intUnsafeCounter, longUnsafeCounter, refUnsafeCounter);

  // now with concurrency
  runAtomicOps(5, 2000000, intJDKCounter, longJDKCounter, refJDKCounter,
      intUnsafeCounter, longUnsafeCounter, refUnsafeCounter);
}
 

/**
 * getAndSet returns previous value and sets to given value
 */
public void testGetAndSet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.getAndSet(this, 0));
    assertEquals(0, a.getAndSet(this, -10));
    assertEquals(-10, a.getAndSet(this, 1));
}
 

/**
 * getAndAdd returns previous value and adds given value
 */
public void testGetAndAdd() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.getAndAdd(this, 2));
    assertEquals(3, a.get(this));
    assertEquals(3, a.getAndAdd(this, -4));
    assertEquals(-1, a.get(this));
}
 

/**
 * getAndDecrement returns previous value and decrements
 */
public void testGetAndDecrement() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.getAndDecrement(this));
    assertEquals(0, a.getAndDecrement(this));
    assertEquals(-1, a.getAndDecrement(this));
}
 

/**
 * getAndIncrement returns previous value and increments
 */
public void testGetAndIncrement() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.getAndIncrement(this));
    assertEquals(2, a.get(this));
    a.set(this, -2);
    assertEquals(-2, a.getAndIncrement(this));
    assertEquals(-1, a.getAndIncrement(this));
    assertEquals(0, a.getAndIncrement(this));
    assertEquals(1, a.get(this));
}
 

/**
 * Creates and returns an updater for objects with the given integer field.
 */
public static <T> AtomicIntegerFieldUpdater<T> newIntegerFieldUpdater(
    Class<T> tclass, String fieldName) {
  if (UnsafeHolder.hasUnsafe()) {
    return new UnsafeAtomicIntegerFieldUpdater<T>(tclass, fieldName);
  }
  else {
    return AtomicIntegerFieldUpdater.newUpdater(tclass, fieldName);
  }
}
 

/** compare raw numbers for atomic ops using JDK vs unsafe wrapper classes */
public void SW_testCompareAtomicOps() {

  final AtomicIntegerFieldUpdater<ConcurrentMapOpsTest> intJDKCounter =
      AtomicIntegerFieldUpdater.newUpdater(ConcurrentMapOpsTest.class,
          "intJDKCounter");
  final AtomicLongFieldUpdater<ConcurrentMapOpsTest> longJDKCounter =
      AtomicLongFieldUpdater.newUpdater(ConcurrentMapOpsTest.class,
          "longJDKCounter");
  final AtomicReferenceFieldUpdater<ConcurrentMapOpsTest, LongRef>
      refJDKCounter = AtomicReferenceFieldUpdater.newUpdater(
          ConcurrentMapOpsTest.class, LongRef.class, "refJDKCounter");

  final AtomicIntegerFieldUpdater<ConcurrentMapOpsTest> intUnsafeCounter =
      AtomicUpdaterFactory.newIntegerFieldUpdater(ConcurrentMapOpsTest.class,
          "intUnsafeCounter");
  final AtomicLongFieldUpdater<ConcurrentMapOpsTest> longUnsafeCounter =
      AtomicUpdaterFactory.newLongFieldUpdater(ConcurrentMapOpsTest.class,
          "longUnsafeCounter");
  final AtomicReferenceFieldUpdater<ConcurrentMapOpsTest, LongRef>
      refUnsafeCounter = AtomicUpdaterFactory.newReferenceFieldUpdater(
          ConcurrentMapOpsTest.class, LongRef.class, "refUnsafeCounter");

  // some warmups
  runAtomicOps(1, 50000, intJDKCounter, longJDKCounter, refJDKCounter,
      intUnsafeCounter, longUnsafeCounter, refUnsafeCounter);

  // timed runs with single threads to see the raw overheads with no
  // concurrency (as we would expect in most usual cases)
  runAtomicOps(1, 50000000, intJDKCounter, longJDKCounter, refJDKCounter,
      intUnsafeCounter, longUnsafeCounter, refUnsafeCounter);

  // now with concurrency
  runAtomicOps(5, 2000000, intJDKCounter, longJDKCounter, refJDKCounter,
      intUnsafeCounter, longUnsafeCounter, refUnsafeCounter);
}
 

/**
 * incrementAndGet increments and returns current value
 */
public void testIncrementAndGet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(2, a.incrementAndGet(this));
    assertEquals(2, a.get(this));
    a.set(this, -2);
    assertEquals(-1, a.incrementAndGet(this));
    assertEquals(0, a.incrementAndGet(this));
    assertEquals(1, a.incrementAndGet(this));
    assertEquals(1, a.get(this));
}
 

/**
 * decrementAndGet decrements and returns current value
 */
public void testDecrementAndGet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(0, a.decrementAndGet(this));
    assertEquals(-1, a.decrementAndGet(this));
    assertEquals(-2, a.decrementAndGet(this));
    assertEquals(-2, a.get(this));
}
 

/**
 * addAndGet adds given value to current, and returns current value
 */
public void testAddAndGet() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(3, a.addAndGet(this, 2));
    assertEquals(3, a.get(this));
    assertEquals(-1, a.addAndGet(this, -4));
    assertEquals(-1, a.get(this));
}
 

/**
 * getAndIncrement returns previous value and increments
 */
public void testGetAndIncrement() {
    AtomicIntegerFieldUpdater<AtomicIntegerFieldUpdaterTest> a;
    a = updaterFor("x");
    x = 1;
    assertEquals(1, a.getAndIncrement(this));
    assertEquals(2, a.get(this));
    a.set(this, -2);
    assertEquals(-2, a.getAndIncrement(this));
    assertEquals(-1, a.getAndIncrement(this));
    assertEquals(0, a.getAndIncrement(this));
    assertEquals(1, a.get(this));
}