Java Code Examples for java.util.concurrent.ExecutorService

/**
 * A submitted failed privileged exception action reports exception
 */
public void testSubmitFailedPrivilegedExceptionAction() throws Exception {
    Runnable r = new CheckedRunnable() {
        public void realRun() throws Exception {
            ExecutorService e = new DirectExecutorService();
            Future future = e.submit(Executors.callable(new PrivilegedExceptionAction() {
                public Object run() throws Exception {
                    throw new IndexOutOfBoundsException();
                }}));

            try {
                future.get();
                shouldThrow();
            } catch (ExecutionException success) {
                assertTrue(success.getCause() instanceof IndexOutOfBoundsException);
            }}};

    runWithPermissions(r);
}
 

private static boolean shutdownExecutor(ExecutorService executor) {
    executor.shutdown();
    try {
        if (!executor.awaitTermination(TIMEOUT_MS, TimeUnit.MILLISECONDS)) {
            executor.shutdownNow();

            return executor.awaitTermination(TIMEOUT_MS, TimeUnit.MILLISECONDS);
        }

        return true;
    } catch (InterruptedException ex) {
        executor.shutdownNow();
        Thread.currentThread().interrupt();
        logger.severe(() -> "Exception: " + ex);
    }
    return false;
}
 

/**
 * Execute the verifier for the given duration.
 *
 * <p>
 * This provides a simple way to execute the verifier for those applications
 * which do not wish to manage threads directly.
 *
 * @param duration amount of time to execute
 * @param unit     units used to express the duration
 * @return number of database rows successfully verified
 */
public long runFor(final long duration, final TimeUnit unit) {
  final long deadline = System.currentTimeMillis() + unit.toMillis(duration);
  final ExecutorService es = Executors.newSingleThreadExecutor();
  final Future<Long> future = es.submit(this);
  try {
    while (System.currentTimeMillis() < deadline && !future.isDone()) {
      Thread.sleep(unit.toMillis(1));
    }
  } catch (final InterruptedException ignored) {
  } finally {
    stop();
  }
  final long result;
  try {
    result = future.get();
  } catch (final InterruptedException | ExecutionException ex) {
    throw new IllegalStateException(ex);
  } finally {
    es.shutdown();
  }
  return result;
}
 

@Test(timeout = 1000L)
public void get_memoizes() throws InterruptedException {
  AtomicInteger provisionCount = new AtomicInteger();

  StorageConsumer storageConsumer = new StorageConsumer() {
    @Override protected StorageComponent tryCompute() {
      provisionCount.incrementAndGet();
      return new InMemoryStorage();
    }
  };

  int getCount = 1000;
  CountDownLatch latch = new CountDownLatch(getCount);
  ExecutorService exec = Executors.newFixedThreadPool(10);
  for (int i = 0; i < getCount; i++) {
    exec.execute(() -> {
      storageConsumer.get();
      latch.countDown();
    });
  }
  latch.await();
  exec.shutdown();
  exec.awaitTermination(1, TimeUnit.SECONDS);

  assertThat(provisionCount.get()).isEqualTo(1);
}
 

private static ExecutorService defaultCleanupExecutor(String metricsGroup, LifeCycleRegistry lifeCycle, MetricRegistry metricRegistry) {
    final Meter meter = metricRegistry.meter(MetricRegistry.name(metricsGroup, "AstyanaxEventReaderDAO", "discarded_slab_cleanup"));
    String nameFormat = "Events Slab Reader Cleanup-" + metricsGroup.substring(metricsGroup.lastIndexOf('.') + 1) + "-%d";
    ExecutorService executor = new ThreadPoolExecutor(
            NUM_CLEANUP_THREADS, NUM_CLEANUP_THREADS,
            0L, TimeUnit.MILLISECONDS,
            new LinkedBlockingQueue<Runnable>(MAX_CLEANUP_QUEUE_LENGTH),
            new ThreadFactoryBuilder().setNameFormat(nameFormat).build(),
            new ThreadPoolExecutor.DiscardPolicy() {
                @Override
                public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
                    meter.mark();
                }
            });
    lifeCycle.manage(new ExecutorServiceManager(executor, Duration.seconds(5), nameFormat));
    return executor;
}
 

/**
 * invokeAny(c) throws ExecutionException if no task completes
 */
public void testInvokeAny4() throws Exception {
    final ExecutorService e =
        new ThreadPoolExecutor(2, 2,
                               LONG_DELAY_MS, MILLISECONDS,
                               new ArrayBlockingQueue<Runnable>(10));
    try (PoolCleaner cleaner = cleaner(e)) {
        List<Callable<String>> l = new ArrayList<Callable<String>>();
        l.add(new NPETask());
        try {
            e.invokeAny(l);
            shouldThrow();
        } catch (ExecutionException success) {
            assertTrue(success.getCause() instanceof NullPointerException);
        }
    }
}
 

public static void fetchOrderSummaryExecutor()
        throws InterruptedException, ExecutionException {

    ExecutorService executor = Executors.newSingleThreadExecutor();

    CompletableFuture<String> cfOrderSummary = CompletableFuture.supplyAsync(() -> {
        try {
            logger.info(() -> "Fetch order summary by: " + Thread.currentThread().getName());
            Thread.sleep(500);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }

        return "Order Summary #91022";
    }, executor);

    String summary = cfOrderSummary.get(); // wait for summary to be available, this is blocking
    logger.info(() -> "Order summary: " + summary + "\n");

    executor.shutdownNow();
}
 

@Test
public void failsFastOnAnyFutureFailure() throws ExecutionException, InterruptedException {
    ExecutorService threadPool = Executors.newFixedThreadPool(10);
    IllegalStateException expectedException = new IllegalStateException("19! Aaargh!");
    CompletableFuture<List<Integer>> integers = IntStream.range(0, 1000)
            .mapToObj(i -> CompletableFuture.supplyAsync(() -> {
                try {
                    Thread.sleep(random.nextInt(100));
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
                if (i == 19) {
                    throw expectedException;
                }
                return i;
            }, threadPool))
            .collect(CompletableFutures.toFutureList());

    AtomicReference<Throwable> exc = new AtomicReference<>();
    integers.handle((success, failure) -> { exc.set(failure.getCause()); return null; }).get();

    assertThat(exc.get(), equalTo(expectedException));
}
 

@Test
@IfProfileValue(name="cas.jpa.concurrent", value="true")
public void verifyConcurrentServiceTicketGeneration() throws Exception {
    final TicketGrantingTicket newTgt = newTGT();
    addTicketInTransaction(newTgt);
    final ExecutorService executor = Executors.newFixedThreadPool(CONCURRENT_SIZE);
    try {
        final List<ServiceTicketGenerator> generators = new ArrayList<>(CONCURRENT_SIZE);
        for (int i = 0; i < CONCURRENT_SIZE; i++) {
            generators.add(new ServiceTicketGenerator(newTgt.getId(), this.jpaTicketRegistry, this.txManager));
        }
        final List<Future<String>> results = executor.invokeAll(generators);
        for (final Future<String> result : results) {
            assertNotNull(result.get());
        }
    } catch (final Exception e) {
        logger.debug("testConcurrentServiceTicketGeneration produced an error", e);
        fail("testConcurrentServiceTicketGeneration failed.");
    } finally {
        executor.shutdownNow();
    }
}
 

/**
 * Get the pool ready to use.
 */
public synchronized ExecutorService getPool ()
{
    if (!creationAllowed) {
        logger.info("No longer allowed to create pool: {}", getName());

        throw new ProcessingCancellationException("Executor closed");
    }

    if (!isActive()) {
        logger.debug("Creating pool: {}", getName());
        pool = createPool();
    }

    return pool;
}
 

/**
 * Creates the executor service used to run map tasks.
 *
 * @return an ExecutorService instance that handles map tasks
 */
protected synchronized ExecutorService createMapExecutor() {

  // Determine the size of the thread pool to use
  int maxMapThreads = job.getInt(LOCAL_MAX_MAPS, 1);
  if (maxMapThreads < 1) {
    throw new IllegalArgumentException(
        "Configured " + LOCAL_MAX_MAPS + " must be >= 1");
  }
  maxMapThreads = Math.min(maxMapThreads, this.numMapTasks);
  maxMapThreads = Math.max(maxMapThreads, 1); // In case of no tasks.

  LOG.debug("Starting mapper thread pool executor.");
  LOG.debug("Max local threads: " + maxMapThreads);
  LOG.debug("Map tasks to process: " + this.numMapTasks);

  // Create a new executor service to drain the work queue.
  ThreadFactory tf = new ThreadFactoryBuilder()
    .setNameFormat("LocalJobRunner Map Task Executor #%d")
    .build();
  ExecutorService executor = Executors.newFixedThreadPool(maxMapThreads, tf);

  return executor;
}
 

/**
 * Execute multiple tasks concurrently.
 *
 * @param numThreads   The number of available threads for concurrent execution.
 * @param tasks        The tasks to execute.
 * @param staggerTasks If true, add delay between task submissions.
 * @param <T>          The return type of the task.
 * @return A list of results for each task executed.
 * @throws InterruptedException if task execution is interrupted.
 */
private <T> List<Future<T>> executeConcurrentTasks(int numThreads, List<Callable<T>> tasks, boolean staggerTasks) throws InterruptedException
{
  final ExecutorService service = Executors.newFixedThreadPool(numThreads);
  List<Future<T>> futures = new ArrayList<>();

  if (staggerTasks) {
    // Necessary to preserve order of requests for certain tests.
    for (Callable<T> task : tasks) {
      futures.add(service.submit(task));
      Thread.sleep(100);
    }
  }
  else {
    futures = service.invokeAll(tasks);
  }
  return futures;
}
 

private void writeToFiles(ExecutorService executor, Map<Pair<RelatedFinder, Object>, List<MithraDataObject>> extract)
{
    UnifiedMap<File, UnifiedMap<RelatedFinder, List<MithraDataObject>>> dataByFile = UnifiedMap.newMap();
    for (Pair<RelatedFinder, Object> key : extract.keySet())
    {
        File outputFile = this.outputStrategy.getOutputFile(key.getOne(), key.getTwo());
        if (outputFile != null)
        {
            dataByFile.getIfAbsentPut(outputFile, UnifiedMap.<RelatedFinder, List<MithraDataObject>>newMap()).put(key.getOne(), extract.get(key));
        }
    }
    for (File file : dataByFile.keySet())
    {
        executor.submit(new FileWriterTask(file, dataByFile.get(file)));
    }
}
 

/**
 * accumulates by multiple threads produce correct result
 */
public void testAccumulateAndGetMT() {
    final int incs = 1000000;
    final int nthreads = 4;
    final ExecutorService pool = Executors.newCachedThreadPool();
    DoubleAccumulator a = new DoubleAccumulator(Double::max, 0.0);
    Phaser phaser = new Phaser(nthreads + 1);
    for (int i = 0; i < nthreads; ++i)
        pool.execute(new AccTask(a, phaser, incs));
    phaser.arriveAndAwaitAdvance();
    phaser.arriveAndAwaitAdvance();
    double expected = incs - 1;
    double result = a.get();
    assertEquals(expected, result);
    pool.shutdown();
}
 

public ThriftConnection(Configuration conf, ExecutorService pool, final User user)
    throws IOException {
  this.conf = conf;
  this.user = user;
  this.host = conf.get(Constants.HBASE_THRIFT_SERVER_NAME);
  this.port = conf.getInt(Constants.HBASE_THRIFT_SERVER_PORT, -1);
  Preconditions.checkArgument(port > 0);
  Preconditions.checkArgument(host != null);
  this.isFramed = conf.getBoolean(Constants.FRAMED_CONF_KEY, Constants.FRAMED_CONF_DEFAULT);
  this.isCompact = conf.getBoolean(Constants.COMPACT_CONF_KEY, Constants.COMPACT_CONF_DEFAULT);
  this.operationTimeout = conf.getInt(HConstants.HBASE_CLIENT_OPERATION_TIMEOUT,
      HConstants.DEFAULT_HBASE_CLIENT_OPERATION_TIMEOUT);
  this.connectTimeout = conf.getInt(SOCKET_TIMEOUT_CONNECT, DEFAULT_SOCKET_TIMEOUT_CONNECT);

  String className = conf.get(Constants.HBASE_THRIFT_CLIENT_BUIDLER_CLASS,
      DefaultThriftClientBuilder.class.getName());
  try {
    Class<?> clazz = Class.forName(className);
    Constructor<?> constructor = clazz
        .getDeclaredConstructor(ThriftConnection.class);
    constructor.setAccessible(true);
    clientBuilder = (ThriftClientBuilder) constructor.newInstance(this);
  }catch (Exception e) {
    throw new IOException(e);
  }
}
 

protected void setAsyncMessageObserverIfNeeded(Exchange exchange) {
    if (!exchange.isSynchronous()) {
        ExecutorService executor = (ExecutorService)cfg.getRequestContext().get(EXECUTOR_SERVICE_PROPERTY);
        if (executor != null) {
            exchange.put(Executor.class, executor);

            final ClientMessageObserver observer = new ClientMessageObserver(cfg);

            exchange.put(MessageObserver.class, message -> {
                if (!message.getExchange().containsKey(Executor.class.getName() + ".USING_SPECIFIED")) {
                    executor.execute(() -> {
                        observer.onMessage(message);
                    });
                } else {
                    observer.onMessage(message);
                }
            });
        }
    }
}
 

@Ignore("See AMQ-4286")
@Test(timeout = 60 * 1000)
public void testLotsOfConcurrentConnections() throws Exception {
   ExecutorService executor = Executors.newCachedThreadPool();
   final ConnectionFactory factory = createConnectionFactory();
   int connectionCount = 400;
   final AtomicInteger threadId = new AtomicInteger(0);
   for (int i = 0; i < connectionCount; i++) {
      executor.execute(new Runnable() {
         @Override
         public void run() {
            final int innerId = threadId.incrementAndGet();
            try {
               ExceptionListener listener = new NioQueueSubscriptionTestListener(innerId, exceptions, LOG);
               ActiveMQConnection connection = (ActiveMQConnection) factory.createConnection();
               connection.setExceptionListener(listener);
               connection.start();
               assertNotNull(connection.getBrokerName());
               connections.add(connection);
            } catch (Exception e) {
               LOG.error(">>>> Exception in run() on thread " + innerId, e);
               exceptions.put(Thread.currentThread(), e);
            }
         }
      });
   }

   executor.shutdown();
   executor.awaitTermination(30, TimeUnit.SECONDS);

   if (!exceptions.isEmpty()) {
      LOG.error(">>>> " + exceptions.size() + " exceptions like", exceptions.values().iterator().next());
      fail("unexpected exceptions in worker threads: " + exceptions.values().iterator().next());
   }
   LOG.info("created " + connectionCount + " connections");
}
 

public static void main (String[] args) throws Exception {
    Handler handler = new Handler();
    InetSocketAddress addr = new InetSocketAddress (0);
    HttpServer server = HttpServer.create(addr, 0);
    HttpContext ctx = server.createContext("/test", handler);
    BasicAuthenticator a = new BasicAuthenticator("[email protected]") {
        @Override
        public boolean checkCredentials (String username, String pw) {
            return "fred".equals(username) && pw.charAt(0) == 'x';
        }
    };

    ctx.setAuthenticator(a);
    ExecutorService executor = Executors.newCachedThreadPool();
    server.setExecutor(executor);
    server.start ();
    java.net.Authenticator.setDefault(new MyAuthenticator());

    System.out.print("Deadlock: " );
    for (int i=0; i<2; i++) {
        Runner t = new Runner(server, i);
        t.start();
        t.join();
    }
    server.stop(2);
    executor.shutdown();
    if (error) {
        throw new RuntimeException("test failed error");
    }

    if (count != 2) {
        throw new RuntimeException("test failed count = " + count);
    }
    System.out.println("OK");

}
 

private static FixClient createFixClient(final InetSocketAddress socketAddress, final SystemConfig systemConfig)
{
    final PublishingConnectionObserver publishingTransportObserver = new PublishingConnectionObserver();

    final ExecutorService executorService = Executors.newSingleThreadExecutor(new NamedThreadFactory("InboundConnection", true, UNCAUGHT_EXCEPTION_HANDLER));
    final AsyncTcpSocketFactory asyncTcpSocketFactory = new AsyncTcpSocketFactory(executorService);
    final TcpTransport transport = new TcpTransport(publishingTransportObserver, socketAddress, asyncTcpSocketFactory, systemConfig);
    publishingTransportObserver.addObserver(transport);
    return buildFixClient(transport, publishingTransportObserver, MAX_MESSAGE_SIZE);
}
 

/**
 * A new newFixedThreadPool can execute runnables
 */
public void testNewFixedThreadPool1() {
    final ExecutorService e = Executors.newFixedThreadPool(2);
    try (PoolCleaner cleaner = cleaner(e)) {
        e.execute(new NoOpRunnable());
        e.execute(new NoOpRunnable());
        e.execute(new NoOpRunnable());
    }
}
 

private static synchronized ExecutorService getExecutorService() {
  if (executorInstance == null) {
    executorInstance = Executors.newCachedThreadPool(new ThreadFactory() {
      
      public Thread newThread(Runnable r) {
        Thread t = new Thread(r);
        t.setDaemon(true);
        return t;
      }
    });
  }
  return executorInstance;
}
 

private static void testLockSync() {
    count = 0;
    ExecutorService executor = Executors.newFixedThreadPool(2);

    IntStream.range(0, NUM_INCREMENTS)
             .forEach(i -> executor.submit(ProgMainExecServiceLock07::incrementSync));

    stop(executor);
    System.out.println(count);
}
 

/**
 * Closes the specified {@link ExecutorService}.
 * @param executorService   The executorService.
 * @return True if shutdown is complete.
 */
public static boolean shutdownExecutorService(ExecutorService executorService) {
  if (executorService == null) {
    return false;
  }
  //If it hasn't already shutdown, do shutdown.
  if (!executorService.isShutdown()) {
    executorService.shutdown();
  }

  try {
    //Wait for clean termination
    if (executorService.awaitTermination(5, TimeUnit.SECONDS)) {
      return true;
    }

    //If not already terminated (via shutdownNow) do shutdownNow.
    if (!executorService.isTerminated()) {
      executorService.shutdownNow();
    }

    if (executorService.awaitTermination(5, TimeUnit.SECONDS)) {
      return true;
    }

    if (LOGGER.isDebugEnabled()) {
      List<Runnable> tasks = executorService.shutdownNow();
      if (!tasks.isEmpty()) {
        LOGGER.debug("ExecutorService was not cleanly shutdown, after waiting for 10 seconds. Number of remaining tasks:" + tasks.size());
      }
    }
  } catch (InterruptedException e) {
    executorService.shutdownNow();
    //Preserve interrupted status
    Thread.currentThread().interrupt();
  }
  return false;
}
 

@Override
public void setup() {
    ExecutorService pool = Executors.newFixedThreadPool(1);
    BlockingQueue<State> q = new ArrayBlockingQueue<>(2000);
    input = q;
    pool.submit(new Producer(q));
    speedDistribution = new AVLTreeDigest(300);
    noise = new Random();

    speed = new Stripchart(10, 430, 460, 80, 1, 0, 0, 90);
    rpm = new Stripchart(10, 520, 460, 80, 1, 0, 0, 2200);
    throttle = new Stripchart(10, 610, 460, 80, 1, 0, 0, 100);

    frameRate(15);
}
 

/**
 * completed submit of callable returns result
 */
public void testSubmitCallable() throws Exception {
    final ExecutorService e =
        new CustomTPE(2, 2,
                      LONG_DELAY_MS, MILLISECONDS,
                      new ArrayBlockingQueue<Runnable>(10));
    try (PoolCleaner cleaner = cleaner(e)) {
        Future<String> future = e.submit(new StringTask());
        String result = future.get();
        assertSame(TEST_STRING, result);
    }
}
 

/**
 * If timed poll returns non-null, the returned task is completed
 */
public void testPoll2() throws InterruptedException {
    final ExecutorService e = Executors.newCachedThreadPool();
    final ExecutorCompletionService ecs = new ExecutorCompletionService(e);
    try (PoolCleaner cleaner = cleaner(e)) {
        assertNull(ecs.poll());
        Callable c = new StringTask();
        ecs.submit(c);
        Future f = ecs.poll(SHORT_DELAY_MS, MILLISECONDS);
        if (f != null)
            assertTrue(f.isDone());
    }
}
 

@Test
@Ignore
public void testMRRunningJobManagerRecoverYarnAppWithLock() throws Exception {
    Assert.assertTrue(curator.checkExists().forPath(SHARE_RESOURCES) != null);
    curator.setData().forPath(SHARE_RESOURCES, generateZkSetData());
    ExecutorService service = Executors.newFixedThreadPool(QTY);
    for (int i = 0; i < QTY; ++i) {
        Callable<Void> task = () -> {
            try {
                MRRunningJobManager mrRunningJobManager = new MRRunningJobManager(zkStateConfig);
                for (int j = 0; j < REPETITIONS; ++j) {
                    if(j % 3 == 0) {
                        mrRunningJobManager.delete("yarnAppId", "jobId");
                    } else {
                        mrRunningJobManager.recoverYarnApp("yarnAppId");
                    }
                }
            } catch (Exception e) {
                // log or do something
            }
            return null;
        };
        service.submit(task);
    }

    service.shutdown();
    service.awaitTermination(10, TimeUnit.MINUTES);
    verify(log, never()).error(anyString(), any(Throwable.class));
}
 

@Override
public void transactionMarker() throws Exception {
    ExecutorService executor = createExecutorService();
    List<Callable<Void>> callables = Lists.newArrayList();
    callables.add(new Callable<Void>() {
        @Override
        public Void call() {
            new CreateTraceEntry().traceEntryMarker();
            return null;
        }
    });
    callables.add(new Callable<Void>() {
        @Override
        public Void call() {
            new CreateTraceEntry().traceEntryMarker();
            return null;
        }
    });
    callables.add(new Callable<Void>() {
        @Override
        public Void call() {
            new CreateTraceEntry().traceEntryMarker();
            return null;
        }
    });
    executor.invokeAny(callables);
}
 

@Test
public void givenDelayQueue_whenTimePass_thenSlotsAvailable() throws InterruptedException {
    final int slots = 50;
    final ExecutorService executorService = Executors.newFixedThreadPool(slots);
    final DelayQueueUsingTimedSemaphore delayQueue = new DelayQueueUsingTimedSemaphore(1, slots);
    IntStream.range(0, slots)
      .forEach(user -> executorService.execute(delayQueue::tryAdd));
    executorService.shutdown();
    executorService.awaitTermination(10, TimeUnit.SECONDS);

    assertEquals(0, delayQueue.availableSlots());
    Thread.sleep(1000);
    assertTrue(delayQueue.availableSlots() > 0);
    assertTrue(delayQueue.tryAdd());
}
 

protected YourFuture actuallyAsync(ConcurrentAsyncCall callback, ExecutorService service, String title) {
    if (isDestructiveAsyncToNormalSync()) { // destructive (for e.g. UnitTest)
        return destructiveNormalSync(callback);
    } else { // basically here
        final String keyword = title + buildExecutorHashExp(service);
        final Callable<WaitingAsyncResult> task = createCallableTask(callback, keyword);
        final Future<WaitingAsyncResult> nativeFuture = service.submit(task); // real asynchronous
        return new BasicYourFuture(nativeFuture);
    }
}