Examples with DbusEvent com.linkedin.databus.core.DbusEvent used on opensource projects

Example 21 with DbusEvent

use of com.linkedin.databus.core.DbusEvent in project databus by linkedin.

the class TestMultiConsumerCallback method test3GroupedStreamConsumersWithFailure.

@Test(groups = { "small", "functional" })
public void test3GroupedStreamConsumersWithFailure() {
    LOG.info("\n\nstarting test3GroupedStreamConsumersWithFailure()");
    Hashtable<Long, AtomicInteger> keyCounts = new Hashtable<Long, AtomicInteger>();
    DbusEventBuffer eventsBuf = new DbusEventBuffer(_generic100KBufferStaticConfig);
    eventsBuf.start(0);
    eventsBuf.startEvents();
    initBufferWithEvents(eventsBuf, 1, 1, (short) 1, keyCounts);
    initBufferWithEvents(eventsBuf, 2, 2, (short) 3, keyCounts);
    eventsBuf.endEvents(100L);
    DatabusStreamConsumer mockConsumer1 = EasyMock.createStrictMock("consumer1", DatabusStreamConsumer.class);
    EasyMock.makeThreadSafe(mockConsumer1, true);
    DatabusStreamConsumer mockConsumer2 = EasyMock.createStrictMock("consumer2", DatabusStreamConsumer.class);
    EasyMock.makeThreadSafe(mockConsumer2, true);
    DatabusStreamConsumer mockConsumer3 = EasyMock.createStrictMock("consumer3", DatabusStreamConsumer.class);
    EasyMock.makeThreadSafe(mockConsumer3, true);
    DatabusCombinedConsumer sdccMockConsumer1 = new SelectingDatabusCombinedConsumer(mockConsumer1);
    DatabusCombinedConsumer sdccMockConsumer2 = new SelectingDatabusCombinedConsumer(mockConsumer2);
    DatabusCombinedConsumer sdccMockConsumer3 = new SelectingDatabusCombinedConsumer(mockConsumer3);
    List<String> sources = new ArrayList<String>();
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    for (int i = 1; i <= 3; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    DatabusV2ConsumerRegistration consumerReg1 = new DatabusV2ConsumerRegistration(Arrays.asList(sdccMockConsumer1, sdccMockConsumer2, sdccMockConsumer3), sources, null);
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg1);
    MultiConsumerCallback callback = new MultiConsumerCallback(allRegistrations, Executors.newCachedThreadPool(), 1000, new StreamConsumerCallbackFactory(null, null), null, null, null, null);
    callback.setSourceMap(sourcesMap);
    DbusEventBuffer.DbusEventIterator iter = eventsBuf.acquireIterator("myIter1");
    assert iter.hasNext() : "unable to read event";
    DbusEvent event1 = iter.next();
    assert iter.hasNext() : "unable to read event";
    DbusEvent event2 = iter.next();
    assert iter.hasNext() : "unable to read event";
    DbusEvent event3 = iter.next();
    initMockFailingStreamConsumer3OptEventFullLifecycle(mockConsumer1, event1, event2, event3, keyCounts);
    initMockFailingStreamConsumer3OptEventFullLifecycle(mockConsumer2, event1, event2, event3, keyCounts);
    initMockFailingStreamConsumer3OptEventFullLifecycle(mockConsumer3, event1, event2, event3, keyCounts);
    assert3EventFullLifecycleWithFailure(callback, event1, event2, event3);
    EasyMock.verify(mockConsumer1);
    EasyMock.verify(mockConsumer2);
    EasyMock.verify(mockConsumer3);
    assert (keyCounts.get(1L).get() + keyCounts.get(2L).get() + keyCounts.get(3L).get()) == 3 : "invalid number of calls: " + keyCounts.get(1L).get() + "," + keyCounts.get(2L).get() + "," + keyCounts.get(3L).get();
}

Example 22 with DbusEvent

use of com.linkedin.databus.core.DbusEvent in project databus by linkedin.

the class TestMultiConsumerCallback method testPerf.

@Test
public void testPerf() throws Exception {
    LOG.info("\n\nstarting testPerf()");
    List<String> sources = new ArrayList<String>();
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    for (int i = 1; i <= 3; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    Hashtable<Long, AtomicInteger> keyCounts = new Hashtable<Long, AtomicInteger>();
    DbusEventBuffer eventsBuf = new DbusEventBuffer(_generic100KBufferStaticConfig);
    eventsBuf.start(0);
    eventsBuf.startEvents();
    initBufferWithEvents(eventsBuf, 1, 1, (short) 1, keyCounts);
    initBufferWithEvents(eventsBuf, 2, 2, (short) 3, keyCounts);
    eventsBuf.endEvents(100L);
    DbusEventBuffer.DbusEventIterator iter = eventsBuf.acquireIterator("myIter1");
    assert iter.hasNext() : "unable to read event";
    iter.next();
    DbusEvent event1 = iter.next();
    DatabusStreamConsumer logConsumer = new LoggingConsumer();
    SelectingDatabusCombinedConsumer sdccLogConsumer = new SelectingDatabusCombinedConsumer(logConsumer);
    DatabusV2ConsumerRegistration consumerReg = new DatabusV2ConsumerRegistration(sdccLogConsumer, sources, null);
    ConsumerCallbackStats consumerStatsCollector = new ConsumerCallbackStats(1, "test", "test", true, false, null);
    UnifiedClientStats unifiedStatsCollector = new UnifiedClientStats(1, "test", "test.unified");
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg);
    ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newCachedThreadPool();
    MultiConsumerCallback callback = new MultiConsumerCallback(allRegistrations, executor, 60000, new StreamConsumerCallbackFactory(consumerStatsCollector, unifiedStatsCollector), consumerStatsCollector, unifiedStatsCollector, null, null);
    callback.setSourceMap(sourcesMap);
    callback.onStartConsumption();
    callback.onStartDataEventSequence(new SingleSourceSCN(1, 1));
    for (int i = 0; i < 10000; ++i) {
        callback.onDataEvent(event1, null);
    }
    callback.onEndDataEventSequence(new SingleSourceSCN(1, 1));
    callback.onStopConsumption();
    System.out.println("max threads=" + executor.getLargestPoolSize() + " task count=" + executor.getTaskCount());
    System.out.println("dataEventsReceived=" + consumerStatsCollector.getNumDataEventsReceived() + " sysEventsReceived=" + consumerStatsCollector.getNumSysEventsReceived() + " dataEventsProcessed=" + consumerStatsCollector.getNumDataEventsProcessed() + " latencyEventsProcessed=" + consumerStatsCollector.getLatencyEventsProcessed());
    long dataEvents = consumerStatsCollector.getNumDataEventsReceived();
    assert (consumerStatsCollector.getNumDataEventsProcessed() == dataEvents);
}

Example 23 with DbusEvent

use of com.linkedin.databus.core.DbusEvent in project databus by linkedin.

the class TestGenericDispatcher method runPartialWindowCheckpointPersistence.

/**
     *
     * @param numEvents : number of events in buffer
     * @param maxWindowSize : window size expressed as number of events
     * @param numFailWindow : nth end-of-window that will fail
     * @throws Exception
     */
void runPartialWindowCheckpointPersistence(int numEvents, int maxWindowSize, int numFailWindow) throws Exception {
    /* Experiment setup */
    int payloadSize = 20;
    int numCheckpoints = numEvents / maxWindowSize;
    /* Consumer creation */
    //setup consumer to fail on data callback at the nth event
    int timeTakenForDataEventInMs = 1;
    int timeTakenForControlEventInMs = 1;
    int numFailCheckpointEvent = 0;
    int numFailDataEvent = 0;
    int numFailEndWindow = numFailWindow;
    int numFailures = 1;
    //fail at the specified window; no retries; so the dispatcher should stop having written one window; but having checkpointed the other
    //thanks to a very small checkpoint frequency threshold
    TimeoutTestConsumer tConsumer = new TimeoutTestConsumer(timeTakenForDataEventInMs, timeTakenForControlEventInMs, numFailCheckpointEvent, numFailDataEvent, numFailEndWindow, numFailures);
    HashMap<Long, List<RegisterResponseEntry>> schemaMap = new HashMap<Long, List<RegisterResponseEntry>>();
    short srcId = 1;
    List<RegisterResponseEntry> l1 = new ArrayList<RegisterResponseEntry>();
    l1.add(new RegisterResponseEntry(1L, srcId, SOURCE1_SCHEMA_STR));
    schemaMap.put(1L, l1);
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    List<String> sources = new ArrayList<String>();
    for (int i = 1; i <= 1; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    long consumerTimeBudgetMs = 60 * 1000;
    DatabusV2ConsumerRegistration consumerReg = new DatabusV2ConsumerRegistration(tConsumer, sources, null);
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg);
    //Single threaded execution of consumer
    MultiConsumerCallback mConsumer = new MultiConsumerCallback(allRegistrations, Executors.newFixedThreadPool(1), consumerTimeBudgetMs, new StreamConsumerCallbackFactory(null, null), null, null, null, null);
    /* Generate events **/
    Vector<DbusEvent> srcTestEvents = new Vector<DbusEvent>();
    Vector<Short> srcIdList = new Vector<Short>();
    srcIdList.add(srcId);
    DbusEventGenerator evGen = new DbusEventGenerator(15000, srcIdList);
    //Assumption: generates events with  non-decreasing timestamps
    Assert.assertTrue(evGen.generateEvents(numEvents, maxWindowSize, 512, payloadSize, true, srcTestEvents) > 0);
    int totalSize = 0;
    int maxSize = 0;
    for (DbusEvent e : srcTestEvents) {
        totalSize += e.size();
        maxSize = (e.size() > maxSize) ? e.size() : maxSize;
    }
    /* Source configuration */
    double thresholdChkptPct = 5.0;
    DatabusSourcesConnection.Config conf = new DatabusSourcesConnection.Config();
    conf.setCheckpointThresholdPct(thresholdChkptPct);
    conf.getDispatcherRetries().setMaxRetryNum(0);
    conf.setFreeBufferThreshold(maxSize);
    conf.setConsumerTimeBudgetMs(consumerTimeBudgetMs);
    int freeBufferThreshold = conf.getFreeBufferThreshold();
    DatabusSourcesConnection.StaticConfig connConfig = conf.build();
    //make buffer large enough to hold data; the control events are large that contain checkpoints
    int producerBufferSize = totalSize * 2 + numCheckpoints * 10 * maxSize * 5 + freeBufferThreshold;
    int individualBufferSize = producerBufferSize;
    int indexSize = producerBufferSize / 10;
    int stagingBufferSize = producerBufferSize;
    /*Event Buffer creation */
    TestGenericDispatcherEventBuffer dataEventsBuffer = new TestGenericDispatcherEventBuffer(getConfig(producerBufferSize, individualBufferSize, indexSize, stagingBufferSize, AllocationPolicy.HEAP_MEMORY, QueuePolicy.BLOCK_ON_WRITE));
    List<DatabusSubscription> subs = DatabusSubscription.createSubscriptionList(sources);
    /* Generic Dispatcher creation */
    InMemoryPersistenceProvider cpPersister = new InMemoryPersistenceProvider();
    TestDispatcher<DatabusCombinedConsumer> dispatcher = new TestDispatcher<DatabusCombinedConsumer>("OnlinePartialWindowCheckpointPersistence", connConfig, subs, cpPersister, dataEventsBuffer, mConsumer, true);
    /* Launch writer */
    DbusEventAppender eventProducer = new DbusEventAppender(srcTestEvents, dataEventsBuffer, 0, null);
    Thread tEmitter = new Thread(eventProducer);
    //be generous ; use worst case for num control events
    long waitTimeMs = (numEvents * timeTakenForDataEventInMs + numEvents * timeTakenForControlEventInMs) * 4;
    tEmitter.start();
    tEmitter.join(waitTimeMs);
    /* Launch dispatcher */
    Thread tDispatcher = new Thread(dispatcher);
    tDispatcher.start();
    /* Now initialize this  state machine */
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesIdsMessage(sourcesMap.values()));
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesSchemasMessage(schemaMap));
    //wait for dispatcher to finish reading the events;
    tDispatcher.join(waitTimeMs);
    Assert.assertFalse(tEmitter.isAlive());
    Assert.assertFalse(tDispatcher.isAlive());
    LOG.info("tConsumer: " + tConsumer);
    HashMap<List<String>, Checkpoint> cps = cpPersister.getCheckpoints();
    for (Map.Entry<List<String>, Checkpoint> i : cps.entrySet()) {
        Checkpoint cp = i.getValue();
        LOG.info("checkpoint=" + cp);
        Assert.assertEquals(cp.getWindowOffset().longValue(), -1L);
        //check if lastSeenCheckpoint by consumer is higher than scn persisted
        Assert.assertTrue(tConsumer.getLastSeenCheckpointScn() > cp.getWindowScn());
        //the latest event seen should be newer (or at least as new) as the checkpoint
        Assert.assertTrue(tConsumer.getLastTsInNanosOfEvent() >= tConsumer.getLastTsInNanosOfWindow());
        if (tConsumer.getLastSeenWindowScn() > 0) {
            Assert.assertEquals(cp.getWindowScn(), tConsumer.getLastSeenWindowScn());
            //check if the timestamp in checkpoint is the same as checkpoint of last completed window (ts of last event of the window)
            Assert.assertEquals(tConsumer.getLastTsInNanosOfWindow(), cp.getTsNsecs());
        } else {
            //not even one window was processed before error; expect uninitialized timestamp
            Assert.assertEquals(Checkpoint.UNSET_TS_NSECS, cp.getTsNsecs());
        }
    }
}

Example 24 with DbusEvent

use of com.linkedin.databus.core.DbusEvent in project databus by linkedin.

the class TestGenericDispatcher method testLargeWindowCheckpointFrequency.

@Test(groups = { "small", "functional" })
public void testLargeWindowCheckpointFrequency() throws Exception {
    final Logger log = Logger.getLogger("TestGenericDispatcher.testLargeWindowCheckpointFrequency");
    log.info("start");
    /* Consumer creation */
    int timeTakenForEventInMs = 1;
    DatabusStreamConsumer tConsumer = new TimeoutTestConsumer(timeTakenForEventInMs);
    DatabusCombinedConsumer sdccTConsumer = new SelectingDatabusCombinedConsumer(tConsumer);
    HashMap<Long, List<RegisterResponseEntry>> schemaMap = new HashMap<Long, List<RegisterResponseEntry>>();
    short srcId = 1;
    List<RegisterResponseEntry> l1 = new ArrayList<RegisterResponseEntry>();
    l1.add(new RegisterResponseEntry(1L, srcId, SOURCE1_SCHEMA_STR));
    schemaMap.put(1L, l1);
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    List<String> sources = new ArrayList<String>();
    for (int i = 1; i <= 1; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    DatabusV2ConsumerRegistration consumerReg = new DatabusV2ConsumerRegistration(sdccTConsumer, sources, null);
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg);
    MultiConsumerCallback mConsumer = new MultiConsumerCallback(allRegistrations, Executors.newFixedThreadPool(2), 1000, new StreamConsumerCallbackFactory(null, null), null, null, null, null);
    /* Source configuration */
    double thresholdChkptPct = 50.0;
    DatabusSourcesConnection.Config conf = new DatabusSourcesConnection.Config();
    conf.setCheckpointThresholdPct(thresholdChkptPct);
    DatabusSourcesConnection.StaticConfig connConfig = conf.build();
    /* Generate events **/
    Vector<DbusEvent> srcTestEvents = new Vector<DbusEvent>();
    Vector<Short> srcIdList = new Vector<Short>();
    srcIdList.add(srcId);
    int numEvents = 100;
    int payloadSize = 20;
    int maxWindowSize = 80;
    DbusEventGenerator evGen = new DbusEventGenerator(0, srcIdList);
    Assert.assertTrue(evGen.generateEvents(numEvents, maxWindowSize, 512, payloadSize, srcTestEvents) > 0);
    int size = 0;
    for (DbusEvent e : srcTestEvents) {
        if (!e.isControlMessage()) {
            size = e.size();
            break;
        }
    }
    //make buffer large enough to hold data
    int producerBufferSize = (int) (numEvents * size * 1.1);
    int individualBufferSize = producerBufferSize;
    int indexSize = producerBufferSize / 10;
    int stagingBufferSize = producerBufferSize;
    /*Event Buffer creation */
    final TestGenericDispatcherEventBuffer dataEventsBuffer = new TestGenericDispatcherEventBuffer(getConfig(producerBufferSize, individualBufferSize, indexSize, stagingBufferSize, AllocationPolicy.HEAP_MEMORY, QueuePolicy.BLOCK_ON_WRITE));
    List<DatabusSubscription> subs = DatabusSubscription.createSubscriptionList(sources);
    /* Generic Dispatcher creation */
    TestDispatcher<DatabusCombinedConsumer> dispatcher = new TestDispatcher<DatabusCombinedConsumer>("freqCkpt", connConfig, subs, new InMemoryPersistenceProvider(), dataEventsBuffer, mConsumer, true);
    /* Launch writer */
    DbusEventAppender eventProducer = new DbusEventAppender(srcTestEvents, dataEventsBuffer, null);
    Thread tEmitter = new Thread(eventProducer);
    tEmitter.start();
    tEmitter.join();
    /* Launch dispatcher */
    Thread tDispatcher = new Thread(dispatcher);
    tDispatcher.start();
    /* Now initialize this damn state machine */
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesIdsMessage(sourcesMap.values()));
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesSchemasMessage(schemaMap));
    Thread.sleep(2000);
    System.out.println("Number of checkpoints = " + dispatcher.getNumCheckPoints());
    Assert.assertTrue(dispatcher.getNumCheckPoints() == 3);
    dispatcher.shutdown();
    verifyNoLocks(null, dataEventsBuffer);
    log.info("end\n");
}

Example 25 with DbusEvent

use of com.linkedin.databus.core.DbusEvent in project databus by linkedin.

the class TestGenericDispatcher method testShutdownBeforeRollback.

@Test(groups = { "small", "functional" })
public /**
     *
     * 1. Dispatcher is dispatching 2 window of events.
     * 2. First window consumption is successfully done.
     * 3. The second window's onStartDataEventSequence() of the callback registered is blocked (interruptible),
     *    causing the dispatcher to wait.
     * 4. At this instant the dispatcher is shut down. The callback is made to return Failure status which would
     *    cause rollback in normal scenario.
     * 5. As the shutdown message is passed, the blocked callback is expected to be interrupted and no rollback
     *    calls MUST be made.
     */
void testShutdownBeforeRollback() throws Exception {
    final Logger log = Logger.getLogger("TestGenericDispatcher.testShutdownBeforeRollback");
    log.setLevel(Level.INFO);
    //log.getRoot().setLevel(Level.DEBUG);
    LOG.info("start");
    // generate events
    Vector<Short> srcIdList = new Vector<Short>();
    srcIdList.add((short) 1);
    DbusEventGenerator evGen = new DbusEventGenerator(0, srcIdList);
    Vector<DbusEvent> srcTestEvents = new Vector<DbusEvent>();
    final int numEvents = 8;
    final int numEventsPerWindow = 4;
    final int payloadSize = 200;
    Assert.assertTrue(evGen.generateEvents(numEvents, numEventsPerWindow, 500, payloadSize, srcTestEvents) > 0);
    // find out how much data we need to stream for the failure
    // account for the EOW event which is < payload size
    int win1Size = payloadSize - 1;
    for (DbusEvent e : srcTestEvents) {
        win1Size += e.size();
    }
    //serialize the events to a buffer so they can be sent to the client
    final TestGenericDispatcherEventBuffer srcEventsBuf = new TestGenericDispatcherEventBuffer(_generic100KBufferStaticConfig);
    DbusEventAppender eventProducer = new DbusEventAppender(srcTestEvents, srcEventsBuf, null, true);
    Thread tEmitter = new Thread(eventProducer);
    tEmitter.start();
    //Create destination (client) buffer
    final TestGenericDispatcherEventBuffer destEventsBuf = new TestGenericDispatcherEventBuffer(_generic100KBufferStaticConfig);
    /**
       *
       *  Consumer with ability to wait for latch during onStartDataEventSequence()
       */
    class TimeoutDESConsumer extends TimeoutTestConsumer {

        private final CountDownLatch latch = new CountDownLatch(1);

        private int _countStartWindow = 0;

        private final int _failedRequestNumber;

        public TimeoutDESConsumer(int failedRequestNumber) {
            super(1, 1, 0, 0, 0, 0);
            _failedRequestNumber = failedRequestNumber;
        }

        public CountDownLatch getLatch() {
            return latch;
        }

        @Override
        public ConsumerCallbackResult onStartDataEventSequence(SCN startScn) {
            _countStartWindow++;
            if (_countStartWindow == _failedRequestNumber) {
                // Wait for the latch to open
                try {
                    latch.await();
                } catch (InterruptedException e) {
                }
                return ConsumerCallbackResult.ERROR_FATAL;
            }
            return super.onStartDataEventSequence(startScn);
        }

        @Override
        public ConsumerCallbackResult onDataEvent(DbusEvent e, DbusEventDecoder eventDecoder) {
            return ConsumerCallbackResult.SUCCESS;
        }

        public int getNumBeginWindowCalls() {
            return _countStartWindow;
        }
    }
    //Create dispatcher
    //fail on second window
    final TimeoutDESConsumer mockConsumer = new TimeoutDESConsumer(2);
    SelectingDatabusCombinedConsumer sdccMockConsumer = new SelectingDatabusCombinedConsumer((DatabusStreamConsumer) mockConsumer);
    List<String> sources = new ArrayList<String>();
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    for (int i = 1; i <= 3; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    DatabusV2ConsumerRegistration consumerReg = new DatabusV2ConsumerRegistration(sdccMockConsumer, sources, null);
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg);
    final ConsumerCallbackStats callbackStats = new ConsumerCallbackStats(0, "test", "test", true, false, null);
    final UnifiedClientStats unifiedStats = new UnifiedClientStats(0, "test", "test.unified");
    MultiConsumerCallback callback = new MultiConsumerCallback(allRegistrations, Executors.newFixedThreadPool(2), // 100 ms budget
    100, new StreamConsumerCallbackFactory(callbackStats, unifiedStats), callbackStats, unifiedStats, null, null);
    callback.setSourceMap(sourcesMap);
    List<DatabusSubscription> subs = DatabusSubscription.createSubscriptionList(sources);
    final RelayDispatcher dispatcher = new RelayDispatcher("dispatcher", _genericRelayConnStaticConfig, subs, new InMemoryPersistenceProvider(), destEventsBuf, callback, null, null, null, null, null);
    final Thread dispatcherThread = new Thread(dispatcher);
    log.info("starting dispatcher thread");
    dispatcherThread.start();
    // Generate RegisterRespone for schema
    HashMap<Long, List<RegisterResponseEntry>> schemaMap = new HashMap<Long, List<RegisterResponseEntry>>();
    List<RegisterResponseEntry> l1 = new ArrayList<RegisterResponseEntry>();
    List<RegisterResponseEntry> l2 = new ArrayList<RegisterResponseEntry>();
    List<RegisterResponseEntry> l3 = new ArrayList<RegisterResponseEntry>();
    l1.add(new RegisterResponseEntry(1L, (short) 1, SOURCE1_SCHEMA_STR));
    l2.add(new RegisterResponseEntry(2L, (short) 1, SOURCE2_SCHEMA_STR));
    l3.add(new RegisterResponseEntry(3L, (short) 1, SOURCE3_SCHEMA_STR));
    schemaMap.put(1L, l1);
    schemaMap.put(2L, l2);
    schemaMap.put(3L, l3);
    // Enqueue Necessary messages before starting dispatch
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesIdsMessage(sourcesMap.values()));
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesSchemasMessage(schemaMap));
    log.info("starting event dispatch");
    //comm channels between reader and writer
    Pipe pipe = Pipe.open();
    Pipe.SinkChannel writerStream = pipe.sink();
    Pipe.SourceChannel readerStream = pipe.source();
    writerStream.configureBlocking(true);
    /*
       *  Needed for DbusEventBuffer.readEvents() to exit their loops when no more data is available.
       *  With Pipe mimicking ChunkedBodyReadableByteChannel, we need to make Pipe non-blocking on the
       *  reader side to achieve the behavior that ChunkedBodyReadableByte channel provides.
       */
    readerStream.configureBlocking(false);
    //Event writer - Relay in the real world
    Checkpoint cp = Checkpoint.createFlexibleCheckpoint();
    //Event readers - Clients in the real world
    //Checkpoint pullerCheckpoint = Checkpoint.createFlexibleCheckpoint();
    DbusEventsStatisticsCollector clientStats = new DbusEventsStatisticsCollector(0, "client", true, false, null);
    DbusEventBufferReader reader = new DbusEventBufferReader(destEventsBuf, readerStream, null, clientStats);
    UncaughtExceptionTrackingThread tReader = new UncaughtExceptionTrackingThread(reader, "Reader");
    tReader.setDaemon(true);
    tReader.start();
    try {
        log.info("send both windows");
        StreamEventsResult streamRes = srcEventsBuf.streamEvents(cp, writerStream, new StreamEventsArgs(win1Size));
        // EOP events, presumably?
        Assert.assertEquals(// EOP events, presumably?
        "num events streamed should equal total number of events plus 2", numEvents + 2, streamRes.getNumEventsStreamed());
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return 2 == mockConsumer.getNumBeginWindowCalls();
            }
        }, "second window processing started", 5000, log);
        dispatcher.shutdown();
        // remove the barrier
        mockConsumer.getLatch().countDown();
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return !dispatcherThread.isAlive();
            }
        }, "Ensure Dispatcher thread is shutdown", 5000, log);
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return 0 == mockConsumer.getNumRollbacks();
            }
        }, "Ensure No Rollback is called", 10, log);
    } finally {
        reader.stop();
    }
    log.info("end\n");
}