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:io.mindmaps.loader.DistributedLoader.java

public DistributedLoader(String graphNameInit, Collection<String> hosts) {
    ConfigProperties prop = ConfigProperties.getInstance();
    batchSize = prop.getPropertyAsInt(ConfigProperties.BATCH_SIZE_PROPERTY);
    graphName = graphNameInit;//ww  w.  j a v  a 2 s  .com
    batch = new HashSet<>();
    hostsArray = hosts.toArray(new String[hosts.size()]);
    currentHost = 0;
    pollingFrequency = 30000;

    threadsNumber = prop.getPropertyAsInt(ConfigProperties.NUM_THREADS_PROPERTY) * 3;

    // create availability map
    availability = new HashMap<>();
    hosts.forEach(h -> availability.put(h, new Semaphore(threadsNumber)));

    jobsTerminated = new HashMap<>();
    hosts.forEach(h -> jobsTerminated.put(h, 0));
}

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From source file:edu.umn.msi.tropix.common.jobqueue.jobprocessors.BaseExecutableJobProcessorFactoryImpl.java

public void setMaxConcurrentProcessingJobs(final String maxConcurrentProcessingJobs) {
    if (StringUtils.hasText(maxConcurrentProcessingJobs) && !maxConcurrentProcessingJobs.startsWith("$")) {
        final int maxConcurrentProcessingJobsInt = Integer.parseInt(maxConcurrentProcessingJobs);
        LOG.info("Constructing job processing semaphore allowing " + maxConcurrentProcessingJobsInt
                + " concurrent jobs to preprocess.");
        final Semaphore semaphore = new Semaphore(maxConcurrentProcessingJobsInt);
        this.processingSemaphore = Optional.of(semaphore);
    }/*from www.  j av  a  2  s. c  om*/
}

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From source file:org.artifactory.storage.binstore.service.providers.FileCacheBinaryProviderImpl.java

@Override
public void initialize() {
    super.initialize();
    lruCache = Maps.newConcurrentMap();/*from w ww.j  av  a 2s.  co  m*/
    totalSize = new AtomicLong(0);
    maxTotalSize = getLongParam("maxSize", getStorageProperties().getBinaryProviderCacheMaxSize());
    cacheCleanerSemaphore = new Semaphore(1);
    syncCacheEntries();
}

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From source file:com.netflix.curator.ensemble.exhibitor.TestExhibitorEnsembleProvider.java

@Test
public void testExhibitorFailures() throws Exception {
    final AtomicReference<String> backupConnectionString = new AtomicReference<String>("backup1:1");
    final AtomicReference<String> connectionString = new AtomicReference<String>(
            "count=1&port=2&server0=localhost");
    Exhibitors exhibitors = new Exhibitors(Lists.newArrayList("foo", "bar"), 1000,
            new Exhibitors.BackupConnectionStringProvider() {
                @Override//from  w  ww.  ja va  2 s. c  o  m
                public String getBackupConnectionString() {
                    return backupConnectionString.get();
                }
            });
    ExhibitorRestClient mockRestClient = new ExhibitorRestClient() {
        @Override
        public String getRaw(String hostname, int port, String uriPath, String mimeType) throws Exception {
            String localConnectionString = connectionString.get();
            if (localConnectionString == null) {
                throw new IOException();
            }
            return localConnectionString;
        }
    };

    final Semaphore semaphore = new Semaphore(0);
    ExhibitorEnsembleProvider provider = new ExhibitorEnsembleProvider(exhibitors, mockRestClient, "/foo", 10,
            new RetryOneTime(1)) {
        @Override
        protected void poll() {
            super.poll();
            semaphore.release();
        }
    };
    provider.pollForInitialEnsemble();
    try {
        provider.start();

        Assert.assertEquals(provider.getConnectionString(), "localhost:2");

        connectionString.set(null);
        semaphore.drainPermits();
        semaphore.acquire(); // wait for next poll
        Assert.assertEquals(provider.getConnectionString(), "backup1:1");

        backupConnectionString.set("backup2:2");
        semaphore.drainPermits();
        semaphore.acquire(); // wait for next poll
        Assert.assertEquals(provider.getConnectionString(), "backup2:2");

        connectionString.set("count=1&port=3&server0=localhost3");
        semaphore.drainPermits();
        semaphore.acquire(); // wait for next poll
        Assert.assertEquals(provider.getConnectionString(), "localhost3:3");
    } finally {
        IOUtils.closeQuietly(provider);
    }
}

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From source file:org.apache.hadoop.hdfs.server.blockmanagement.TestBlockReportRateLimiting.java

@Test(timeout = 180000)
public void testRateLimitingDuringDataNodeStartup() throws Exception {
    Configuration conf = new Configuration();
    conf.setInt(DFS_NAMENODE_MAX_FULL_BLOCK_REPORT_LEASES, 1);
    conf.setLong(DFS_NAMENODE_FULL_BLOCK_REPORT_LEASE_LENGTH_MS, 20L * 60L * 1000L);

    final Semaphore fbrSem = new Semaphore(0);
    final HashSet<DatanodeID> expectedFbrDns = new HashSet<>();
    final HashSet<DatanodeID> fbrDns = new HashSet<>();
    final AtomicReference<String> failure = new AtomicReference<String>("");

    final BlockManagerFaultInjector injector = new BlockManagerFaultInjector() {
        private int numLeases = 0;

        @Override/*from w  w w.  j  a  va  2 s.  c  o  m*/
        public void incomingBlockReportRpc(DatanodeID nodeID, BlockReportContext context) throws IOException {
            LOG.info("Incoming full block report from " + nodeID + ".  Lease ID = 0x"
                    + Long.toHexString(context.getLeaseId()));
            if (context.getLeaseId() == 0) {
                setFailure(failure,
                        "Got unexpected rate-limiting-" + "bypassing full block report RPC from " + nodeID);
            }
            fbrSem.acquireUninterruptibly();
            synchronized (this) {
                fbrDns.add(nodeID);
                if (!expectedFbrDns.remove(nodeID)) {
                    setFailure(failure, "Got unexpected full block report " + "RPC from " + nodeID
                            + ".  expectedFbrDns = " + Joiner.on(", ").join(expectedFbrDns));
                }
                LOG.info("Proceeding with full block report from " + nodeID + ".  Lease ID = 0x"
                        + Long.toHexString(context.getLeaseId()));
            }
        }

        @Override
        public void requestBlockReportLease(DatanodeDescriptor node, long leaseId) {
            if (leaseId == 0) {
                return;
            }
            synchronized (this) {
                numLeases++;
                expectedFbrDns.add(node);
                LOG.info("requestBlockReportLease(node=" + node + ", leaseId=0x" + Long.toHexString(leaseId)
                        + ").  " + "expectedFbrDns = " + Joiner.on(", ").join(expectedFbrDns));
                if (numLeases > 1) {
                    setFailure(failure, "More than 1 lease was issued at once.");
                }
            }
        }

        @Override
        public void removeBlockReportLease(DatanodeDescriptor node, long leaseId) {
            LOG.info("removeBlockReportLease(node=" + node + ", leaseId=0x" + Long.toHexString(leaseId) + ")");
            synchronized (this) {
                numLeases--;
            }
        }
    };
    BlockManagerFaultInjector.instance = injector;

    final int NUM_DATANODES = 5;
    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(NUM_DATANODES).build();
    cluster.waitActive();
    for (int n = 1; n <= NUM_DATANODES; n++) {
        LOG.info("Waiting for " + n + " datanode(s) to report in.");
        fbrSem.release();
        Uninterruptibles.sleepUninterruptibly(20, TimeUnit.MILLISECONDS);
        final int currentN = n;
        GenericTestUtils.waitFor(new Supplier<Boolean>() {
            @Override
            public Boolean get() {
                synchronized (injector) {
                    if (fbrDns.size() > currentN) {
                        setFailure(failure,
                                "Expected at most " + currentN
                                        + " datanodes to have sent a block report, but actually "
                                        + fbrDns.size() + " have.");
                    }
                    return (fbrDns.size() >= currentN);
                }
            }
        }, 25, 50000);
    }
    cluster.shutdown();
    Assert.assertEquals("", failure.get());
}

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From source file:com.taobao.gecko.service.impl.DefaultRemotingContext.java

public DefaultRemotingContext(final BaseConfig config, final CommandFactory commandFactory) {
    this.groupManager = new GroupManager();
    this.config = config;
    if (commandFactory == null) {
        throw new IllegalArgumentException("CommandFactory");
    }//from   w w  w .j a  v  a  2 s.c  om
    this.commandFactory = commandFactory;
    this.callBackSemaphore = new Semaphore(this.config.getMaxCallBackCount());
    MBeanUtils.registerMBeanWithIdPrefix(this, null);
}

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From source file:org.jbpm.EventCallback.java

private static Semaphore getEventSemaphore(String event) {
    synchronized (eventSemaphores) {
        Semaphore semaphore = eventSemaphores.get(event);
        if (semaphore == null) {
            semaphore = new Semaphore(0);
            eventSemaphores.put(event, semaphore);
        }// ww  w . j  a va  2 s. c  o m
        return semaphore;
    }
}

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From source file:com.netflix.curator.framework.recipes.locks.TestInterProcessSemaphoreCluster.java

@Test
public void testKilledServerWithEnsembleProvider() throws Exception {
    final int CLIENT_QTY = 10;
    final Timing timing = new Timing();
    final String PATH = "/foo/bar/lock";

    ExecutorService executorService = Executors.newFixedThreadPool(CLIENT_QTY);
    ExecutorCompletionService<Void> completionService = new ExecutorCompletionService<Void>(executorService);
    TestingCluster cluster = new TestingCluster(3);
    try {//from w w w . jav a  2 s. com
        cluster.start();

        final AtomicReference<String> connectionString = new AtomicReference<String>(
                cluster.getConnectString());
        final EnsembleProvider provider = new EnsembleProvider() {
            @Override
            public void start() throws Exception {
            }

            @Override
            public String getConnectionString() {
                return connectionString.get();
            }

            @Override
            public void close() throws IOException {
            }
        };

        final Semaphore acquiredSemaphore = new Semaphore(0);
        final AtomicInteger acquireCount = new AtomicInteger(0);
        final CountDownLatch suspendedLatch = new CountDownLatch(CLIENT_QTY);
        for (int i = 0; i < CLIENT_QTY; ++i) {
            completionService.submit(new Callable<Void>() {
                @Override
                public Void call() throws Exception {
                    CuratorFramework client = CuratorFrameworkFactory.builder().ensembleProvider(provider)
                            .sessionTimeoutMs(timing.session()).connectionTimeoutMs(timing.connection())
                            .retryPolicy(new ExponentialBackoffRetry(100, 3)).build();
                    try {
                        final Semaphore suspendedSemaphore = new Semaphore(0);
                        client.getConnectionStateListenable().addListener(new ConnectionStateListener() {
                            @Override
                            public void stateChanged(CuratorFramework client, ConnectionState newState) {
                                if ((newState == ConnectionState.SUSPENDED)
                                        || (newState == ConnectionState.LOST)) {
                                    suspendedLatch.countDown();
                                    suspendedSemaphore.release();
                                }
                            }
                        });

                        client.start();

                        InterProcessSemaphoreV2 semaphore = new InterProcessSemaphoreV2(client, PATH, 1);

                        while (!Thread.currentThread().isInterrupted()) {
                            Lease lease = null;
                            try {
                                lease = semaphore.acquire();
                                acquiredSemaphore.release();
                                acquireCount.incrementAndGet();
                                suspendedSemaphore.acquire();
                            } catch (Exception e) {
                                // just retry
                            } finally {
                                if (lease != null) {
                                    acquireCount.decrementAndGet();
                                    IOUtils.closeQuietly(lease);
                                }
                            }
                        }
                    } finally {
                        IOUtils.closeQuietly(client);
                    }
                    return null;
                }
            });
        }

        Assert.assertTrue(timing.acquireSemaphore(acquiredSemaphore));
        Assert.assertEquals(1, acquireCount.get());

        cluster.close();
        timing.awaitLatch(suspendedLatch);
        timing.forWaiting().sleepABit();
        Assert.assertEquals(0, acquireCount.get());

        cluster = new TestingCluster(3);
        cluster.start();

        connectionString.set(cluster.getConnectString());
        timing.forWaiting().sleepABit();

        Assert.assertTrue(timing.acquireSemaphore(acquiredSemaphore));
        timing.forWaiting().sleepABit();
        Assert.assertEquals(1, acquireCount.get());
    } finally {
        executorService.shutdown();
        executorService.awaitTermination(10, TimeUnit.SECONDS);
        executorService.shutdownNow();
        IOUtils.closeQuietly(cluster);
    }
}

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From source file:com.alibaba.napoli.gecko.service.impl.DefaultRemotingContext.java

public DefaultRemotingContext(final BaseConfig config, final CommandFactory commandFactory) {
    this.groupManager = new GroupManager();
    this.config = config;
    if (commandFactory == null) {
        throw new IllegalArgumentException("CommandFactory?");
    }//from w  ww .j  a va2s.c o  m
    this.commandFactory = commandFactory;
    this.callBackSemaphore = new Semaphore(this.config.getMaxCallBackCount());
    MBeanUtils.registerMBeanWithIdPrefix(this, null);
}

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

protected Semaphore createPollSemaphore() {
    return new Semaphore(taskExecutorThreadPoolSize);
}

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