Example usage for java.util.concurrent Semaphore Semaphore

Introduction

In this page you can find the example usage for java.util.concurrent Semaphore Semaphore.

Prototype

public Semaphore(int permits) 

Source Link

Document

Creates a Semaphore with the given number of permits and nonfair fairness setting.

Usage

From source file:com.bt.aloha.batchtest.ultramonkey.SyncServiceImpl.java

@Override
public String makeCall(String caller, String callee) {
    String callId = null;//from   w  w w . j  ava 2  s . c om
    synchronized (makeCallLock) {
        callId = super.makeCall(caller, callee);
        callConnectedSemaphores.put(callId, new Semaphore(0));
    }
    if (waitForCallConnectedEvent(callId)) {
        return callId;
    }
    throw new ServiceException("No call connected event received for callId " + callId);
}

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From source file:com.solace.samples.BasicRequestor.java

public void run(String... args) {
    System.out.println("BasicRequestor initializing...");

    try {//from ww w.  j a va  2  s  .  c o  m
        // Create an Mqtt client
        final MqttClient mqttClient = new MqttClient("tcp://" + args[0], "HelloWorldBasicRequestor");
        MqttConnectOptions connOpts = new MqttConnectOptions();
        connOpts.setCleanSession(true);

        // Connect the client
        System.out.println("Connecting to Solace broker: tcp://" + args[0]);
        mqttClient.connect(connOpts);
        System.out.println("Connected");

        // Semaphore used for synchronizing b/w threads
        final Semaphore latch = new Semaphore(0);

        // Topic the client will use to send request messages
        final String requestTopic = "T/GettingStarted/request";

        // Callback - Anonymous inner-class for receiving the Reply-To topic from the Solace broker
        mqttClient.setCallback(new MqttCallback() {
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                // If the topic is "$SYS/client/reply-to" then set our replyToTopic
                // to with the contents of the message payload received
                if (topic != null && topic.equals("$SYS/client/reply-to")) {
                    replyToTopic = new String(message.getPayload());
                    System.out.println("\nReceived Reply-to topic from Solace for the MQTT client:"
                            + "\n\tReply-To: " + replyToTopic + "\n");
                } else {
                    // Received a response to our request
                    try {
                        // Parse the response payload and convert to a JSONObject
                        Object obj = parser.parse(new String(message.getPayload()));
                        JSONObject jsonPayload = (JSONObject) obj;

                        System.out.println("\nReceived a response!" + "\n\tCorrel. Id: "
                                + (String) jsonPayload.get("correlationId") + "\n\tMessage:    "
                                + (String) jsonPayload.get("message") + "\n");
                    } catch (ParseException ex) {
                        System.out.println("Exception parsing response message!");
                        ex.printStackTrace();
                    }
                }

                latch.release(); // unblock main thread
            }

            public void connectionLost(Throwable cause) {
                System.out.println("Connection to Solace broker lost!" + cause.getMessage());
                latch.release();
            }

            public void deliveryComplete(IMqttDeliveryToken token) {
            }
        });

        // Subscribe client to the special Solace topic for requesting a unique
        // Reply-to destination for the MQTT client
        System.out.println("Requesting Reply-To topic from Solace...");
        mqttClient.subscribe("$SYS/client/reply-to", 0);

        // Wait for till we have received the reply to Topic
        try {
            latch.acquire();
        } catch (InterruptedException e) {
            System.out.println("I was awoken while waiting");
        }

        // Check if we have a Reply-To topic
        if (replyToTopic == null || replyToTopic.isEmpty()) {
            System.out.println("Unable to request Reply-To from Solace. Exiting");
            System.exit(0);
        }

        // Subscribe client to the Solace provide Reply-To topic with a QoS level of 0
        System.out.println("Subscribing client to Solace provide Reply-To topic");
        mqttClient.subscribe(replyToTopic, 0);

        // Create the request payload in JSON format
        JSONObject obj = new JSONObject();
        obj.put("correlationId", UUID.randomUUID().toString());
        obj.put("replyTo", replyToTopic);
        obj.put("message", "Sample Request");
        String reqPayload = obj.toJSONString();

        // Create a request message and set the request payload
        MqttMessage reqMessage = new MqttMessage(reqPayload.getBytes());
        reqMessage.setQos(0);

        System.out.println("Sending request to: " + requestTopic);

        // Publish the request message
        mqttClient.publish(requestTopic, reqMessage);

        // Wait for till we have received a response
        try {
            latch.acquire(); // block here until message received
        } catch (InterruptedException e) {
            System.out.println("I was awoken while waiting");
        }

        // Disconnect the client
        mqttClient.disconnect();
        System.out.println("Exiting");

        System.exit(0);
    } catch (MqttException me) {
        System.out.println("reason " + me.getReasonCode());
        System.out.println("msg " + me.getMessage());
        System.out.println("loc " + me.getLocalizedMessage());
        System.out.println("cause " + me.getCause());
        System.out.println("excep " + me);
        me.printStackTrace();
    }
}

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From source file:com.amazonaws.services.simpleworkflow.flow.worker.ActivityTaskPoller.java

public void setTaskExecutorService(ThreadPoolExecutor taskExecutorService) {
    this.taskExecutorService = taskExecutorService;
    pollSemaphore = new Semaphore(taskExecutorService.getMaximumPoolSize());
}

---

From source file:com.pinterest.rocksplicator.controller.WorkerPoolTest.java

@Test
public void testAssignSameCluster() throws Exception {
    Semaphore idleWorkersSemaphore = new Semaphore(0);
    ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(1, 1, 0, TimeUnit.SECONDS,
            new ArrayBlockingQueue<Runnable>(1));
    WorkerPool workerPool = new WorkerPool(threadPoolExecutor, idleWorkersSemaphore, new TaskQueue() {
    });//from w w w.  j  ava2  s . com
    Task task = getSleepIncrementTask();
    workerPool.assignTask(task);
    Thread.sleep(2000);
    Assert.assertEquals(1, SleepIncrementTask.executionCounter.intValue());
    workerPool.assignTask(task);
    Thread.sleep(2000);
    Assert.assertEquals(2, (int) SleepIncrementTask.executionCounter);
    Assert.assertEquals(2, idleWorkersSemaphore.availablePermits());
}

---

From source file:com.netflix.curator.framework.recipes.cache.TestNodeCache.java

@Test
public void testDeleteThenCreate() throws Exception {
    NodeCache cache = null;/*from   w  w  w .j  a  v a2  s  . c o m*/
    CuratorFramework client = CuratorFrameworkFactory.newClient(server.getConnectString(), new RetryOneTime(1));
    client.start();
    try {
        client.create().creatingParentsIfNeeded().forPath("/test/foo", "one".getBytes());

        final AtomicReference<Throwable> error = new AtomicReference<Throwable>();
        client.getUnhandledErrorListenable().addListener(new UnhandledErrorListener() {
            @Override
            public void unhandledError(String message, Throwable e) {
                error.set(e);
            }
        });

        final Semaphore semaphore = new Semaphore(0);
        cache = new NodeCache(client, "/test/foo");
        cache.getListenable().addListener(new NodeCacheListener() {
            @Override
            public void nodeChanged() throws Exception {
                semaphore.release();
            }
        });
        cache.start(true);

        Assert.assertEquals(cache.getCurrentData().getData(), "one".getBytes());

        client.delete().forPath("/test/foo");
        Assert.assertTrue(semaphore.tryAcquire(1, 10, TimeUnit.SECONDS));
        client.create().forPath("/test/foo", "two".getBytes());
        Assert.assertTrue(semaphore.tryAcquire(1, 10, TimeUnit.SECONDS));

        Throwable t = error.get();
        if (t != null) {
            Assert.fail("Assert", t);
        }

        Assert.assertEquals(cache.getCurrentData().getData(), "two".getBytes());

        cache.close();
    } finally {
        IOUtils.closeQuietly(cache);
        IOUtils.closeQuietly(client);
    }
}

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From source file:io.hops.erasure_coding.ReedSolomonDecoder.java

public ReedSolomonDecoder(Configuration conf) {
    super(conf, Codec.getCodec("rs"));
    this.reedSolomonCode = new ReedSolomonCode[parallelism];
    stripeSize = this.codec.stripeLength;
    paritySize = this.codec.parityLength;
    for (int i = 0; i < parallelism; i++) {
        reedSolomonCode[i] = new ReedSolomonCode(stripeSize, paritySize);
    }/*from   w  w w .  j  a  v  a  2  s  .c  om*/
    decodeOps = new Semaphore(parallelism);
}

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From source file:org.wso2.carbon.analytics.eventsink.internal.queue.AnalyticsEventQueue.java

@SuppressWarnings("unchecked")
public AnalyticsEventQueue(int tenantId) {
    Disruptor<WrappedEventFactory.WrappedEvent> eventQueue = new Disruptor<>(new WrappedEventFactory(),
            ServiceHolder.getAnalyticsEventSinkConfiguration().getQueueSize(), Executors.newCachedThreadPool());
    eventQueue.handleEventsWith(new AnalyticsEventQueueWorker(tenantId, this));
    this.currentEventSize = 0;
    this.ringBuffer = eventQueue.start();
    this.currentSize = new AtomicInteger(0);
    this.maxSize = ServiceHolder.getAnalyticsEventSinkConfiguration().getMaxQueueCapacity();
    this.semaphore = new Semaphore(1);
    if (log.isDebugEnabled()) {
        log.debug("Event Queue Size = " + ServiceHolder.getAnalyticsEventSinkConfiguration().getQueueSize());
    }//from w  ww .  jav  a 2 s  .c o  m
}

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From source file:com.netflix.curator.x.discovery.TestServiceDiscovery.java

@Test
public void testCrashedServerMultiInstances() throws Exception {
    List<Closeable> closeables = Lists.newArrayList();
    TestingServer server = new TestingServer();
    closeables.add(server);/*from   www  .  ja  va  2  s.com*/
    try {
        Timing timing = new Timing();
        CuratorFramework client = CuratorFrameworkFactory.newClient(server.getConnectString(), timing.session(),
                timing.connection(), new RetryOneTime(1));
        closeables.add(client);
        client.start();

        final Semaphore semaphore = new Semaphore(0);
        ServiceInstance<String> instance1 = ServiceInstance.<String>builder().payload("thing").name("test")
                .port(10064).build();
        ServiceInstance<String> instance2 = ServiceInstance.<String>builder().payload("thing").name("test")
                .port(10065).build();
        ServiceDiscovery<String> discovery = new ServiceDiscoveryImpl<String>(client, "/test",
                new JsonInstanceSerializer<String>(String.class), instance1) {
            @Override
            protected void internalRegisterService(ServiceInstance<String> service) throws Exception {
                super.internalRegisterService(service);
                semaphore.release();
            }
        };
        closeables.add(discovery);
        discovery.start();
        discovery.registerService(instance2);

        timing.acquireSemaphore(semaphore, 2);
        Assert.assertEquals(discovery.queryForInstances("test").size(), 2);

        KillSession.kill(client.getZookeeperClient().getZooKeeper(), server.getConnectString());
        server.stop();

        server = new TestingServer(server.getPort(), server.getTempDirectory());
        closeables.add(server);

        timing.acquireSemaphore(semaphore, 2);
        Assert.assertEquals(discovery.queryForInstances("test").size(), 2);
    } finally {
        for (Closeable c : closeables) {
            IOUtils.closeQuietly(c);
        }
    }
}

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From source file:frames.CreatePublisher.java

public CreatePublisher() {

    initComponents();//w w  w . ja v a  2 s . c  o m

    //Create semaphore with a single permission
    semaphore = new Semaphore(1);

    //Centralizes frame
    setLocationRelativeTo(null);

    //Make CreatePublisher frame visible
    setVisible(true);

}

---

From source file:com.pinterest.rocksplicator.controller.DispatcherTest.java

@Test
public void testNoPendingTask() throws Exception {
    // Assuming there is no task in the queue in the test.
    PowerMockito.when(taskQueue.dequeueTask(anyString())).thenReturn(null);
    Semaphore idleWorkersSemaphore = new Semaphore(1);
    ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(1, 1, 0, TimeUnit.SECONDS,
            new ArrayBlockingQueue<Runnable>(1));
    WorkerPool workerPool = new WorkerPool(threadPoolExecutor, idleWorkersSemaphore, taskQueue);
    TaskDispatcher dispatcher = new TaskDispatcher(1, idleWorkersSemaphore, workerPool, taskQueue);
    dispatcher.start();/*w ww  .  j av  a2 s.c om*/
    Thread.sleep(1000);
    Assert.assertEquals(1, idleWorkersSemaphore.availablePermits());
    Thread.sleep(1000);
    Assert.assertEquals(1, idleWorkersSemaphore.availablePermits());
    dispatcher.stop();
}

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