Java Examples for java.util.concurrent.ThreadLocalRandom

@Test
public void loadSecretKey() throws Exception {
    byte[] secretBytes = new byte[32];
    ThreadLocalRandom.current().nextBytes(secretBytes);
    SecretKeySpec expected = new SecretKeySpec(secretBytes, "HmacSHA256");
    SecretKey actual = KeyUtils.loadSecretKey(secretBytes);
    assertEquals(expected.getAlgorithm(), actual.getAlgorithm());
    assertArrayEquals(expected.getEncoded(), actual.getEncoded());
}

private long generateHour() {
    int hour = ThreadLocalRandom.current().nextInt(simulationInput.getHoursFieldMin(), simulationInput.getHoursFieldMax() + 1);
    int minute = ThreadLocalRandom.current().nextInt(0, 61);
    SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss");
    Date d = null;
    try {
        d = sdf.parse("15/04/2016 " + hour + ":" + minute + ":00");
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return d.getTime();
}

public Card getRandomOfType(CardType cardType) {
    List<Card> relevantCards = new ArrayList<>();
    for (Card card : cards) {
        if (card.getCardType().isCardType(cardType)) {
            relevantCards.add(card);
        }
    }
    if (relevantCards.isEmpty()) {
        return null;
    }
    return relevantCards.get(ThreadLocalRandom.current().nextInt(relevantCards.size()));
}

/** Delays are emulated using exponential distribution of probabilities. */
public long evaluateDelay() {
    if (meanDelay > 0) {
        // Network delays (network delays). Delays should be emulated using exponential distribution of probabilities.
        // log(1-x)/(1/mean)
        Double x0 = ThreadLocalRandom.current().nextDouble();
        Double y0 = -Math.log(1 - x0) * meanDelay;
        return y0.longValue();
    }
    return 0;
}

@Override
public void emitBatch(long batchId, TridentCollector collector) {
    List<List<Object>> values = null;
    if (batches.containsKey(batchId)) {
        values = batches.get(batchId);
    } else {
        values = new ArrayList<>();
        for (int i = 0; i < batchSize; i++) {
            List<Object> numbers = new ArrayList<>();
            for (int x = 0; x < fields.size(); x++) {
                numbers.add(ThreadLocalRandom.current().nextInt(0, maxNumber + 1));
            }
            values.add(numbers);
        }
        batches.put(batchId, values);
    }
    for (List<Object> value : values) {
        collector.emit(value);
    }
}

public Object createdata() {
    double lowerBound = 0;
    double upperBound = 1;
    /**
         * value to add for Math.random() to include upperBound - to choose random value between 0 to 1 (inclusive of both)
         */
    double incrementValue = 0.1d;
    Boolean inValidData = true;
    BigDecimal randomValue = null;
    while (inValidData) {
        randomValue = new BigDecimal(ThreadLocalRandom.current().nextDouble(lowerBound, upperBound + incrementValue));
        Boolean isNegative = (0 == ThreadLocalRandom.current().nextInt(2)) ? true : false;
        // i.e., if the precision is say 5, then get unscaledRandom%10^5
        if (randomValue.compareTo(new BigDecimal("1")) >= 0) {
            randomValue = randomValue.movePointRight(precision - scale - 1);
        } else {
            randomValue = randomValue.movePointRight(precision - scale);
        }
        randomValue = randomValue.setScale(scale, RoundingMode.FLOOR);
        randomValue = (isNegative) ? randomValue.multiply(new BigDecimal("-1")) : randomValue;
        // must be 0 or -ve
        int exceedsMax = randomValue.compareTo((BigDecimal) maxvalue);
        // must be 0 or +ve
        int exceedsMin = randomValue.compareTo((BigDecimal) minvalue);
        // than max bigdecimal
        if (!((exceedsMin < 0) || (exceedsMax > 0))) {
            inValidData = false;
        }
    }
    return randomValue;
}

@Override
public long getDelay(int numAttempts, HealthCheckResult result) {
    checkArgument(numAttempts >= 1);
    checkNotNull(result);
    // Pick a random number between baseDelay*2^(n-1) and baseDelay*2^n (inclusive), subject
    // to the upper bound.
    long rangeMax = Math.min(_baseDelay * (1 << numAttempts), _maxDelayMillis);
    long rangeMin = rangeMax / 2;
    return rangeMin + ThreadLocalRandom.current().nextLong(rangeMax - rangeMin + 1);
}

private void build() {
    // emulate the work of building this product, by sleeping
    Integer elapsed = ThreadLocalRandom.current().nextInt(0, this.bound);
    try {
        sleep(elapsed);
        // increase counters for this product, another completed!
        totalTime.inc(elapsed);
        completed.inc();
    } catch (InterruptedException e) {
        failures.inc();
    }
}

private void runHyperLoopStress(String label) {
    System.out.println("=====in Round " + label);
    int numRunnings0 = numOfRunningThreads();
    CountDownLatch endLatch = new CountDownLatch(1);
    String[] values = new String[RUNS];
    ThreadLocalRandom rnd = ThreadLocalRandom.current();
    for (int i = 0; i < RUNS; i++) {
        values[i] = String.valueOf(rnd.nextLong());
    }
    System.out.println("start stress...");
    Thread t = new Thread(() -> {
        Affinity.bindTo(Topology.socket(0).physicalCore(3).virtualCore(0));
        String v;
        for (int i = 0; i < RUNS; i++) {
            while (out.notReceivable()) {
            }
            v = out.tryReceive();
            //        if (!v.equals(values[i])) {
            //          //DEBUG
            //          for (int j = 0; j < values.length; j++) {
            //            if (v.equals(j))
            //              System.out.println("i:"+i+",j:"+j);
            //          }
            //         System.out.println("======#####=====");
            //        }
            assertThat("happend when i=" + i, v, is(values[i]));
        }
        endLatch.countDown();
    });
    t.setDaemon(true);
    t.start();
    try {
        long s = System.nanoTime();
        //XXX: producer is in main thread
        for (int i = 0; i < RUNS; i++) {
            while (!loop.trySend(values[i])) {
            }
        }
        endLatch.await();
        long time = System.nanoTime() - s;
        System.out.printf("done with costed time: %,d\n", time);
        assertThat(numOfRunningThreads(), is(numRunnings0));
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void sawOpcode(int seen) {
    if (seen == Constants.INVOKESPECIAL && getClassConstantOperand().equals("java/util/Random") && getNameConstantOperand().equals("<init>")) {
        bugReporter.reportBug(//
        new BugInstance(this, PREDICTABLE_RANDOM_TYPE, Priorities.NORMAL_PRIORITY).addClass(this).addMethod(this).addSourceLine(//
        this).addString("java.util.Random"));
    } else if (seen == Constants.INVOKESTATIC && getClassConstantOperand().equals("java/lang/Math") && getNameConstantOperand().equals("random")) {
        bugReporter.reportBug(//
        new BugInstance(this, PREDICTABLE_RANDOM_TYPE, Priorities.NORMAL_PRIORITY).addClass(this).addMethod(this).addSourceLine(//
        this).addString("java.lang.Math.random()"));
    } else if (seen == Constants.INVOKESTATIC && getClassConstantOperand().equals("java/util/concurrent/ThreadLocalRandom") && getNameConstantOperand().equals("current")) {
        bugReporter.reportBug(//
        new BugInstance(this, PREDICTABLE_RANDOM_TYPE, Priorities.NORMAL_PRIORITY).addClass(this).addMethod(this).addSourceLine(//
        this).addString("java.util.concurrent.ThreadLocalRandom"));
    } else if (seen == Constants.INVOKESPECIAL && getClassConstantOperand().equals("scala/util/Random") && getNameConstantOperand().equals("<init>")) {
        bugReporter.reportBug(//
        new BugInstance(this, PREDICTABLE_RANDOM_SCALA_TYPE, Priorities.NORMAL_PRIORITY).addClass(this).addMethod(this).addSourceLine(//
        this).addString("scala.util.Random"));
    } else if (seen == Constants.INVOKEVIRTUAL && RANDOM_NEXT_METHODS.matches(this)) {
        bugReporter.reportBug(//
        new BugInstance(this, PREDICTABLE_RANDOM_SCALA_TYPE, Priorities.NORMAL_PRIORITY).addClass(this).addMethod(this).addSourceLine(//
        this).addString("scala.util.Random." + getNameConstantOperand() + "()"));
    }
}

@ProcessElement
public void processElement(ProcessContext context, BoundedWindow window) throws IOException {
    ThreadLocalRandom randomGenerator = ThreadLocalRandom.current();
    // We output on keys 0-numShards.
    String tableSpec = context.element().getKey().getTableSpec();
    context.output(KV.of(ShardedKey.of(tableSpec, randomGenerator.nextInt(0, numShards)), context.element().getValue()));
}

public void start(String token) {
    super.start();
    send("login " + token);
    nioEventLoopGroup.scheduleAtFixedRate(() -> {
        send(makeCommand("vw 4 " + ThreadLocalRandom.current().nextInt(100)));
        send(makeCommand("dw 3 " + ThreadLocalRandom.current().nextInt(255)));
        send(makeCommand("dw 0 " + buttonVal));
        send(makeCommand("vw 5 " + (buttonVal == 1 ? 255 : 0)));
        send(makeCommand("vw 6 " + ledVal));
        send(makeCommand("aw 6 " + ledVal));
        send(makeCommand("vw 10 p 0 0 ledVal:" + ledVal));
        if (buttonVal == 1) {
            buttonVal = 0;
        } else {
            buttonVal = 1;
        }
        if (ledVal > 255) {
            ledVal = 0;
            send(makeCommand("vw 10 clr"));
        } else {
            ledVal += 20;
        }
    }, 1, 1, TimeUnit.SECONDS);
}

@Override
public ServiceDefinition choose(List<ServiceDefinition> definitions) {
    // Fail if the service definition list is null or empty
    if (ObjectHelper.isEmpty(definitions)) {
        throw new IllegalArgumentException("The ServiceDefinition list should not be empty");
    }
    int size = definitions.size();
    if (size == 1) {
        return definitions.get(0);
    } else {
        return definitions.get(ThreadLocalRandom.current().nextInt(size));
    }
}

public Collection<ItemStack> getDrops(GlowBlock block, ItemStack tool) {
    ThreadLocalRandom random = ThreadLocalRandom.current();
    int count = minCount;
    if (maxCount > minCount) {
        count += random.nextInt(maxCount - minCount);
    }
    ItemStack stack = new ItemStack(dropType, count, (short) data);
    if (tool == null) {
        return Collections.unmodifiableList(Arrays.asList(stack));
    }
    Collection<ItemStack> drops = super.getDrops(block, tool);
    if (drops.size() == 0) {
        return drops;
    }
    if (tool.containsEnchantment(Enchantment.LOOT_BONUS_BLOCKS)) {
        stack.setAmount(count * getMultiplicator(random, tool.getEnchantmentLevel(Enchantment.LOOT_BONUS_BLOCKS)));
    }
    return Collections.unmodifiableList(Arrays.asList(stack));
}

private void getNextEntries(LocalDate begin, LocalDate end, Consumer<List<WeekViewAppointment<Object>>> consumer) {
    ThreadLocalRandom random = ThreadLocalRandom.current();
    LinkedList<WeekViewAppointment<Object>> retval = new LinkedList<>();
    LocalDate firstDayOfWeek = begin;
    for (int i = 0; i < 7; i++) {
        LocalDate current = firstDayOfWeek.plusDays(i);
        LocalTime time = LocalTime.of(random.nextInt(6, 18), random.nextInt(3) * 15);
        int minutes = Math.max(15, random.nextInt(12) * 15);
        Duration duration = Duration.ofMinutes(minutes);
        LocalDateTime localDateTime = LocalDateTime.of(current, time);
        BiPredicate<LocalDate, LocalTime> newTimePossiblePredicate = ( newDate,  newTime) -> {
            if (newTime == null) {
                return true;
            }
            if (newTime.getHour() > 6 && newTime.getHour() < 22) {
                return true;
            } else {
                log.info("Wrong time {}", newTime);
                return false;
            }
        };
        WeekViewAppointment<Object> timedAppointment = new WeekViewAppointment<>("test entry" + i + " " + minutes + "m", localDateTime, duration);
        timedAppointment.setChangeStartCallback(( newDate,  newTime) -> {
            log.info("{} now starts on {} {}", timedAppointment.getTitle(), newDate, newTime);
        });
        timedAppointment.setNewTimePossiblePredicate(newTimePossiblePredicate);
        retval.add(timedAppointment);
        for (int j = 0; j < random.nextInt(1, 4); j++) {
            WeekViewAppointment<Object> dayAppointment = new WeekViewAppointment<>(j + " test day spanning entry" + i + " " + minutes + "m", localDateTime.toLocalDate(), duration);
            dayAppointment.setChangeStartCallback(( newDate,  newTime) -> {
                log.info("{} now starts on {} {}", dayAppointment.getTitle(), newDate, newTime);
            });
            dayAppointment.setNewTimePossiblePredicate(newTimePossiblePredicate);
            retval.add(dayAppointment);
        }
    }
    consumer.accept(retval);
}

/** {@inheritDoc} */
@Override
public boolean test(Map<Object, Object> ctx) throws Exception {
    double salary = ThreadLocalRandom.current().nextDouble() * args.range() * 1000;
    double maxSalary = salary + 1000;
    Collection<List<?>> lists = executeQueryJoin(salary, maxSalary);
    for (List<?> l : lists) {
        double sal = (Double) l.get(4);
        if (sal < salary || sal > maxSalary) {
            Person p = new Person();
            p.setId((Integer) l.get(0));
            p.setOrganizationId((Integer) l.get(1));
            p.setFirstName((String) l.get(2));
            p.setLastName((String) l.get(3));
            p.setSalary(sal);
            throw new Exception("Invalid person retrieved [min=" + salary + ", max=" + maxSalary + ", person=" + p + ']');
        }
    }
    return true;
}

public Observable<LogRow> getLogs() {
    SerializedSubject<LogRow, LogRow> subject = new SerializedSubject<>(PublishSubject.create());
    ThreadFactory threadFactory = new ThreadFactoryBuilder().setDaemon(true).setNameFormat(Example_8_Model.class.getSimpleName() + "-thread-%d").build();
    final ExecutorService executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors(), threadFactory);
    IntStream.range(1, Runtime.getRuntime().availableProcessors() + 1).forEach( value -> {
        executorService.submit(() -> {
            SysOutUtils.sysout(Thread.currentThread().getName() + " will briefly start creating lots of log rows...");
            VariousUtils.sleep(1000);
            long incrementingNumber = 1;
            while (true) {
                subject.onNext(new LogRow(DateTimeFormatter.ISO_DATE_TIME.format(LocalDateTime.now()), "Status " + Integer.toString(ThreadLocalRandom.current().nextInt(1, 5)), "Action " + incrementingNumber + " from " + Thread.currentThread().getName()));
            }
        });
    });
    return subject;
}

@Override
public void emitBatch(long batchId, TridentCollector collector) {
    List<List<Object>> values = null;
    if (batches.containsKey(batchId)) {
        values = batches.get(batchId);
    } else {
        values = new ArrayList<>();
        for (int i = 0; i < batchSize; i++) {
            List<Object> numbers = new ArrayList<>();
            for (int x = 0; x < fields.size(); x++) {
                numbers.add(ThreadLocalRandom.current().nextInt(0, maxNumber + 1));
            }
            values.add(numbers);
        }
        batches.put(batchId, values);
    }
    for (List<Object> value : values) {
        collector.emit(value);
    }
}

public void run() {
    int latestId = 0;
    Integer ackIt = null;
    while (received.size() < NUMBER_OF_MESSAGES) {
        Message tm = t.take(Message.class);
        if (tm instanceof Broadcast) {
            Broadcast bs = (Broadcast) tm;
            try {
                BroadcastTestMessage hw = (BroadcastTestMessage) MmsMessage.tryRead(bs);
                int id = hw.getId();
                assertEquals(latestId++, id);
                received.add(id);
            } catch (Exception e) {
                e.printStackTrace();
            }
            ackIt = null;
        } else {
            if (ackIt == null) {
                ackIt = ThreadLocalRandom.current().nextInt(ack.get(), latestId + 1);
            }
            ack.set(ackIt);
            latestId = ackIt;
            t.send(new Connected().setSessionId(BIN1).setLastReceivedMessageId((long) ackIt));
        }
    }
}

/**
	 * Test that startup doesn't throw exceptions
	 * 
	 * things not covered:
	 * - routing table loading
	 * - delayed tasks
	 * - bootstrap name resolution
	 * - bootstrap ping attempts
	 */
@Test
public void testStartup() throws Exception {
    int port = ThreadLocalRandom.current().nextInt(1024, 65535);
    CompletableFuture<Boolean> exceptionCanary = new CompletableFuture<>();
    ScheduledThreadPoolExecutor scheduler = new ScheduledThreadPoolExecutor(1, new ThreadFactory() {

        @Override
        public Thread newThread(Runnable r) {
            Thread t = new Thread(r);
            t.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {

                @Override
                public void uncaughtException(Thread t, Throwable e) {
                    exceptionCanary.completeExceptionally(e);
                }
            });
            return t;
        }
    });
    DHT dhtInstance = new DHT(DHTtype.IPV4_DHT);
    // TODO: refactor to per-instance logger
    DHT.setLogger(new DHTLogger() {

        @Override
        public void log(Throwable t, LogLevel l) {
            // allow bootstrap node resolution to fail in test environment
            if (t instanceof UnknownHostException)
                return;
            exceptionCanary.completeExceptionally(t);
        }

        @Override
        public void log(String message, LogLevel l) {
        }
    });
    dhtInstance.setScheduler(scheduler);
    Path storagePath = Paths.get(".", "does", "not", "exist");
    dhtInstance.start(new DHTConfiguration() {

        @Override
        public boolean noRouterBootstrap() {
            return true;
        }

        @Override
        public boolean isPersistingID() {
            return false;
        }

        @Override
        public Path getStoragePath() {
            return storagePath;
        }

        @Override
        public int getListeningPort() {
            return port;
        }

        @Override
        public boolean allowMultiHoming() {
            return false;
        }
    });
    assertEquals(DHTStatus.Initializing, dhtInstance.getStatus());
    // bootstrap is called synchronously during startup and should fall straight through, thus reset the state
    assertEquals(DHT.BootstrapState.NONE, dhtInstance.bootstrapping.get());
    assertEquals(1, dhtInstance.getServerManager().getServerCount());
    CompletableFuture<Boolean> wasEmpty = new CompletableFuture<>();
    // single-threaded executor -> we can let startup tasks complete and then stop the DHT from the pool itself
    // thus there should be no pending tasks on the executor
    scheduler.execute(() -> {
        dhtInstance.stop();
        scheduler.purge();
        wasEmpty.complete(scheduler.getQueue().isEmpty());
    });
    assertTrue("no tasks should remain queued after stop()", wasEmpty.get());
    assertEquals(DHTStatus.Stopped, dhtInstance.getStatus());
    assertEquals("no messages should have been sent on a bootstrapless startup", 0, dhtInstance.getStats().getNumSentPackets());
    scheduler.shutdown();
    assertTrue("all tasks terminated", scheduler.awaitTermination(10, TimeUnit.MILLISECONDS));
    exceptionCanary.complete(true);
    // check for async exceptions
    exceptionCanary.get();
    assertFalse("should not create storage path, that's the caller's duty", Files.isDirectory(storagePath));
}

@Override
protected Referer<T> doSelect(Request request) {
    List<Referer<T>> referers = getReferers();
    int refererSize = referers.size();
    int startIndex = ThreadLocalRandom.current().nextInt(refererSize);
    int currentCursor = 0;
    int currentAvailableCursor = 0;
    Referer<T> referer = null;
    while (currentAvailableCursor < MAX_REFERER_COUNT && currentCursor < refererSize) {
        Referer<T> temp = referers.get((startIndex + currentCursor) % refererSize);
        currentCursor++;
        if (!temp.isAvailable()) {
            continue;
        }
        currentAvailableCursor++;
        if (referer == null) {
            referer = temp;
        } else {
            if (compare(referer, temp) > 0) {
                referer = temp;
            }
        }
    }
    return referer;
}

@Override
public UUID generateRandomUuid() {
    final Random rnd = ThreadLocalRandom.current();
    long mostSig = rnd.nextLong();
    long leastSig = rnd.nextLong();
    // Identify this as a version 4 UUID, that is one based on a random value.
    mostSig &= 0xffffffffffff0fffL;
    mostSig |= 0x0000000000004000L;
    // Set the variant identifier as specified for version 4 UUID values.  The two
    // high order bits of the lower word are required to be one and zero, respectively.
    leastSig &= 0x3fffffffffffffffL;
    leastSig |= 0x8000000000000000L;
    return new UUID(mostSig, leastSig);
}

@Override
public boolean attempt(Callable<Boolean> operation) {
    try {
        ThreadLocalRandom random = ThreadLocalRandom.current();
        int remainingAttempts = _maximumAttemptCount - 1;
        long minimumSleepTime = _minimumMilliseconds;
        long maximumSleepTime = (long) (minimumSleepTime * _retryScaleFactor);
        boolean result = operation.call();
        while ((!result) && (0 < remainingAttempts)) {
            long sleepTime = random.nextLong(minimumSleepTime, maximumSleepTime);
            Uninterruptibles.sleepUninterruptibly(sleepTime, TimeUnit.MILLISECONDS);
            result = operation.call();
            remainingAttempts--;
            minimumSleepTime *= _retryScaleFactor;
            maximumSleepTime *= _retryScaleFactor;
        }
        return result;
    } catch (Exception e) {
        Utils.rethrowException(e);
        return false;
    }
}

private GameMapBuilder createRiver(Tile tile, int size) {
    int randomNum = ThreadLocalRandom.current().nextInt(0, height - size);
    for (int z = 0; z < depth; z++) {
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < size; y++) {
                tiles.put(new Point(x, (y + randomNum), z), tile);
            }
        }
    }
    return this;
}

private static TableDefinition generateTableDefinition() {
    StringBuilder createTableDdl = new StringBuilder();
    createTableDdl.append("CREATE EXTERNAL TABLE %NAME%(");
    createTableDdl.append("   col INT");
    createTableDdl.append(") ");
    createTableDdl.append("PARTITIONED BY (part_col INT) ");
    createTableDdl.append(" STORED AS ORC");
    HiveDataSource dataSource = createResourceDataSource(TABLE_NAME, String.valueOf(ThreadLocalRandom.current().nextLong(Long.MAX_VALUE)), "com/facebook/presto/tests/hive/data/single_int_column/data.orc");
    HiveDataSource invalidData = createStringDataSource(TABLE_NAME, String.valueOf(ThreadLocalRandom.current().nextLong(Long.MAX_VALUE)), "INVALID DATA");
    return HiveTableDefinition.builder(TABLE_NAME).setCreateTableDDLTemplate(createTableDdl.toString()).addPartition("part_col = 1", invalidData).addPartition("part_col = 2", dataSource).build();
}

/**
     * Returns a cryptographically generated id.
     * 
     * @return id
     */
public static final long generateId() {
    long id = 0;
    // add new seed material from current time
    random.addSeedMaterial(ThreadLocalRandom.current().nextLong());
    // get a new id
    byte[] bytes = new byte[16];
    // get random bytes
    random.nextBytes(bytes);
    for (int i = 0; i < bytes.length; i++) {
        id += ((long) bytes[i] & 0xffL) << (8 * i);
    }
    //System.out.println("Id: " + id);
    return id;
}

@Test
public void testByteBuffers() {
    byte[] bytes = new byte[1000];
    ThreadLocalRandom.current().nextBytes(bytes);
    final Memory memory = Memory.allocate(bytes.length);
    memory.setBytes(0, bytes, 0, bytes.length);
    ByteBuffer canon = ByteBuffer.wrap(bytes).order(ByteOrder.nativeOrder());
    test(canon, memory);
    memory.setBytes(0, new byte[1000], 0, 1000);
    memory.setBytes(0, canon.duplicate());
    test(canon, memory);
    memory.close();
}

@Test
public void testEstimates() throws Exception {
    int trials = 1000;
    for (int indexBits = 4; indexBits <= 13; indexBits++) {
        Map<Integer, Stats> errors = new HashMap<>();
        int numberOfBuckets = 1 << indexBits;
        int maxCardinality = numberOfBuckets * 2;
        for (int trial = 0; trial < trials; trial++) {
            HyperLogLog hll = HyperLogLog.newInstance(numberOfBuckets);
            for (int cardinality = 1; cardinality <= maxCardinality; cardinality++) {
                hll.add(ThreadLocalRandom.current().nextLong());
                if (cardinality % (numberOfBuckets / 10) == 0) {
                    // only do this a few times, since computing the cardinality is currently not
                    // as cheap as it should be
                    double error = (hll.cardinality() - cardinality) * 1.0 / cardinality;
                    Stats stats = errors.get(cardinality);
                    if (stats == null) {
                        stats = new Stats();
                        errors.put(cardinality, stats);
                    }
                    stats.add(error);
                }
            }
        }
        double expectedStandardError = 1.04 / Math.sqrt(1 << indexBits);
        for (Map.Entry<Integer, Stats> entry : errors.entrySet()) {
            // Give an extra error margin. This is mostly a sanity check to catch egregious errors
            assertTrue(entry.getValue().stdev() <= expectedStandardError * 1.1, String.format("Failed at p = %s, cardinality = %s. Expected std error = %s, actual = %s", indexBits, entry.getKey(), expectedStandardError, entry.getValue().stdev()));
        }
    }
}

ColumnSelection select() {
    if (settings.columns.slice) {
        int count = (int) columnCount.next();
        int start;
        if (count == settings.columns.maxColumnsPerKey)
            start = 0;
        else
            start = 1 + ThreadLocalRandom.current().nextInt(settings.columns.maxColumnsPerKey - count);
        return new ColumnSelection(null, start, start + count);
    }
    int count = (int) columnCount.next();
    int totalCount = settings.columns.names.size();
    if (count == settings.columns.names.size())
        return new ColumnSelection(null, 0, count);
    ThreadLocalRandom rnd = ThreadLocalRandom.current();
    int[] indices = new int[count];
    int c = 0, o = 0;
    while (c < count && count + o < totalCount) {
        int leeway = totalCount - (count + o);
        int spreadover = count - c;
        o += Math.round(rnd.nextDouble() * (leeway / (double) spreadover));
        indices[c] = o + c;
        c++;
    }
    while (c < count) {
        indices[c] = o + c;
        c++;
    }
    return new ColumnSelection(indices, 0, 0);
}

ColumnSelection select() {
    if (settings.columns.slice) {
        int count = (int) columnCount.next();
        int start;
        if (count == settings.columns.maxColumnsPerKey)
            start = 0;
        else
            start = 1 + ThreadLocalRandom.current().nextInt(settings.columns.maxColumnsPerKey - count);
        return new ColumnSelection(null, start, start + count);
    }
    int count = (int) columnCount.next();
    int totalCount = settings.columns.names.size();
    if (count == settings.columns.names.size())
        return new ColumnSelection(null, 0, count);
    ThreadLocalRandom rnd = ThreadLocalRandom.current();
    int[] indices = new int[count];
    int c = 0, o = 0;
    while (c < count && count + o < totalCount) {
        int leeway = totalCount - (count + o);
        int spreadover = count - c;
        o += Math.round(rnd.nextDouble() * (leeway / (double) spreadover));
        indices[c] = o + c;
        c++;
    }
    while (c < count) {
        indices[c] = o + c;
        c++;
    }
    return new ColumnSelection(indices, 0, 0);
}

private static void test(Function<ChronicleMapBuilder<Integer, Integer>, ChronicleMap<Integer, Integer>> createMap) {
    long ms = System.currentTimeMillis();
    try (ChronicleMap<Integer, Integer> map = createMap.apply(ChronicleMapBuilder.of(Integer.class, Integer.class).entries(ENTRIES).entriesPerSegment((1 << 15) / 3).checksumEntries(false).putReturnsNull(true).removeReturnsNull(true))) {
        Random r = ThreadLocalRandom.current();
        for (int i = 0; i < ENTRIES; i++) {
            map.put(r.nextInt(), r.nextInt());
        }
    }
    System.out.println(System.currentTimeMillis() - ms);
}

private String shuffleWithFisherYates(String tokenStringToShuffle) {
    char[] shuffleArray = tokenStringToShuffle.toCharArray();
    int tokenLength = tokenStringToShuffle.length();
    for (int i = 0; i < (tokenLength - 2); i++) {
        int j = ThreadLocalRandom.current().nextInt(i, tokenLength);
        shuffleArray = this.swap(shuffleArray, i, j);
    }
    return new String(shuffleArray);
}

/**
     * Generate a random UUID v4 that will perform reasonably when used by
     * multiple threads under load.
     *
     * @see https://github.com/Netflix/netflix-commons/blob/v0.3.0/netflix-commons-util/src/main/java/com/netflix/util/concurrent/ConcurrentUUIDFactory.java
     * @return random UUID
     */
private static UUID generateRandomUuid() {
    final Random rnd = ThreadLocalRandom.current();
    long mostSig = rnd.nextLong();
    long leastSig = rnd.nextLong();
    // Identify this as a version 4 UUID, that is one based on a random value.
    mostSig &= 0xffffffffffff0fffL;
    mostSig |= 0x0000000000004000L;
    // Set the variant identifier as specified for version 4 UUID values.  The two
    // high order bits of the lower word are required to be one and zero, respectively.
    leastSig &= 0x3fffffffffffffffL;
    leastSig |= 0x8000000000000000L;
    return new UUID(mostSig, leastSig);
}

@Override
public Response toResponse(E exception) {
    if (exception instanceof WebApplicationException) {
        return ((WebApplicationException) exception).getResponse();
    }
    boolean debuggable = isDebuggable();
    final long id = ThreadLocalRandom.current().nextLong();
    /*
         * If we are a BaseWebApplicationException then we will use its data to build a 
         * response.
         */
    if (exception instanceof BaseWebApplicationException) {
        ResponseBuilder builder = ((BaseWebApplicationException) exception).createResponseBuilder();
        if (!debuggable) {
            return builder.entity(new ErrorMessage(exception.getMessage())).build();
        } else {
            builder.entity(new DebugErrorMessage(id, exception));
            debugLogException(id, exception);
            return builder.build();
        }
    }
    //here we have an unexpected exception of some kind (its not a BaseWebApplicationException)
    //we must sanitize the exception message we send back to the client 
    //unless its debuggable
    logException(id, exception);
    if (debuggable) {
        return Response.serverError().entity(new DebugErrorMessage(id, exception)).build();
    } else {
        return Response.serverError().entity(new ErrorMessage(formatErrorMessage(id))).build();
    }
}

@RequestMapping(value = "{id}/order", method = RequestMethod.GET)
public String orderMovie(@PathVariable UUID id, Model model) {
    log.info("orderMovie with id " + id);
    Movie movie = movieService.getMovieById(id);
    // Create some default shipping details
    Address address = new Address(Locale.GERMANY.getDisplayCountry(), "Cologne", "50667", "Domkloster", "4");
    Recipient recipient = new Recipient("Alexander", "Mustermann", address, address);
    Integer amount = ThreadLocalRandom.current().nextInt(1, 15);
    Order order = new Order(amount, movie.getId().toString(), recipient);
    BigDecimal totalPrice = movie.getPrice().multiply(BigDecimal.valueOf(amount));
    model.addAttribute("movie", movie);
    model.addAttribute("order", order);
    model.addAttribute("totalPrice", totalPrice);
    ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
    try {
        String orderAsJson = ow.writeValueAsString(order);
        messageChannel.send(new GenericMessage<String>(orderAsJson));
    } catch (JsonProcessingException e) {
        e.printStackTrace();
    }
    return "order";
}

// set the scavenge interval carefully
public synchronized void scavenge() throws InterruptedException {
    int delta = this.totalCount - config.getMinSize();
    if (delta <= 0)
        return;
    int removed = 0;
    long now = System.currentTimeMillis();
    Poolable<T> obj;
    while (delta-- > 0 && (obj = objectQueue.poll()) != null) {
        // so it could take several intervals to shrink the pool to the configured min value.
        if (Log.isDebug())
            Log.debug("obj=", obj, ", now-last=", now - obj.getLastAccessTs(), ", max idle=", config.getMaxIdleMilliseconds());
        if (now - obj.getLastAccessTs() > config.getMaxIdleMilliseconds() && ThreadLocalRandom.current().nextDouble(1) < config.getScavengeRatio()) {
            // shrink the pool size if the object reaches max idle time
            decreaseObject(obj);
            removed++;
        } else {
            //put it back
            objectQueue.put(obj);
        }
    }
    if (removed > 0)
        Log.debug(removed, " objects were scavenged.");
}

public static void main(String[] args) throws Exception {
    final int parallelism = Integer.parseInt(args[0]);
    final String checkpointPath = args[1];
    final int checkpointingInterval = Integer.parseInt(args[2]);
    final String outputPath = args[3];
    StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
    env.setParallelism(parallelism);
    env.getConfig().disableSysoutLogging();
    env.enableCheckpointing(checkpointingInterval);
    env.setStateBackend(new FsStateBackend(checkpointPath));
    DataStream<Integer> source = env.addSource(new InfiniteIntegerSource());
    source.map(new MapFunction<Integer, Tuple2<Integer, Integer>>() {

        private static final long serialVersionUID = 1L;

        @Override
        public Tuple2<Integer, Integer> map(Integer value) throws Exception {
            return new Tuple2<>(ThreadLocalRandom.current().nextInt(parallelism), value);
        }
    }).keyBy(new KeySelector<Tuple2<Integer, Integer>, Integer>() {

        private static final long serialVersionUID = 1L;

        @Override
        public Integer getKey(Tuple2<Integer, Integer> value) throws Exception {
            return value.f0;
        }
    }).flatMap(new ReducingStateFlatMap()).writeAsText(outputPath);
    env.execute();
}

@Override
public Move stateMachineSelectMove(long timeout) throws TransitionDefinitionException, MoveDefinitionException, GoalDefinitionException {
    long start = System.currentTimeMillis();
    List<Move> moves = getStateMachine().getLegalMoves(getCurrentState(), getRole());
    Move selection = (moves.get(ThreadLocalRandom.current().nextInt(moves.size())));
    long stop = System.currentTimeMillis();
    notifyObservers(new GamerSelectedMoveEvent(moves, selection, stop - start));
    return selection;
}

@BeforeClass
public static void setUp() throws IOException {
    UTIL.getConfiguration().setLong(StoreScanner.STORESCANNER_PREAD_MAX_BYTES, 2048);
    StringBuilder sb = new StringBuilder(256);
    for (int i = 0; i < 255; i++) {
        sb.append((char) ThreadLocalRandom.current().nextInt('A', 'z' + 1));
    }
    VALUE_PREFIX = sb.append("-").toString();
    REGION = UTIL.createLocalHRegion(new HTableDescriptor(TABLE_NAME).addFamily(new HColumnDescriptor(FAMILY).setBlocksize(1024)), null, null);
    for (int i = 0; i < 900; i++) {
        REGION.put(new Put(Bytes.toBytes(i)).addColumn(FAMILY, QUAL, Bytes.toBytes(VALUE_PREFIX + i)));
    }
    REGION.flush(true);
    for (int i = 900; i < 1000; i++) {
        REGION.put(new Put(Bytes.toBytes(i)).addColumn(FAMILY, QUAL, Bytes.toBytes(VALUE_PREFIX + i)));
    }
}

@Override
public void run() {
    for (int i = 0; i < ITERATIONS; i++) {
        limiter.acquire();
        ThreadLocalRandom random = ThreadLocalRandom.current();
        int playerId = random.nextInt(ENTITIES);
        if (random.nextDouble() < 0.7) {
            playerDao.update(playerId, i);
        } else {
            playerDao.get(playerId);
        }
    }
}

@Override
public Response toResponse(AtlasBaseException exception) {
    final long id = ThreadLocalRandom.current().nextLong();
    // Only log the exception is there's an internal error
    if (exception.getAtlasErrorCode().getHttpCode() == Response.Status.INTERNAL_SERVER_ERROR) {
        ExceptionMapperUtil.logException(id, exception);
    }
    return buildAtlasBaseExceptionResponse(exception);
}

@Override
public void run() {
    ThreadLocalRandom random = ThreadLocalRandom.current();
    InternalCacheEntry ice;
    while (!terminate) {
        long lifespan;
        String key = key(random);
        switch(random.nextInt(3)) {
            case 0:
                lifespan = random.nextInt(3) == 0 ? random.nextInt(10) : -1;
                ice = TestInternalCacheEntryFactory.<Object, Object>create(factory, key(random), String.valueOf(random.nextInt()), lifespan);
                store.write(TestingUtil.marshalledEntry(ice, marshaller));
                break;
            case 1:
                store.delete(key);
                break;
            case 2:
                store.load(key);
        }
    }
}

public String random5to10Name() {
    int randLength = 5 + ThreadLocalRandom.current().nextInt(6);
    StringBuilder sb = new StringBuilder(randLength);
    sb.append(firstLetter.charAt(ThreadLocalRandom.current().nextInt(firstLetter.length())));
    for (int i = 0; i < randLength - 1; i++) sb.append(numsAndLetters.charAt(ThreadLocalRandom.current().nextInt(numsAndLetters.length())));
    return sb.toString();
}

public void run() {
    ThreadLocalRandom rand = ThreadLocalRandom.current();
    List<SimpleCollection.Node> items = new ArrayList<>();
    while (System.nanoTime() < until) {
        int targetSize = rand.nextInt(maxSignalsPerThread);
        while (items.size() < targetSize) items.add(c.add(new Object()));
        while (items.size() > targetSize) items.remove(rand.nextInt(items.size())).remove();
        if (!present(c, items.iterator()))
            System.err.println("fail");
    }
    latch.countDown();
}

private long doBenchmark(InvokeTargetResolver resolver, Collection<String> keys) {
    long ret = 0;
    long begin = System.nanoTime();
    for (String key : keys) {
        int hash = resolver.resolve(key, "GET").hashCode();
        ret += hash;
    }
    long dur = System.nanoTime() - begin;
    if (ThreadLocalRandom.current().nextInt(100000) == 1) {
        System.out.println("Please ignore: " + ret);
    }
    return dur;
}

@Override
public boolean tryLock(long time, TimeUnit unit, String... names) throws InterruptedException {
    long start = System.currentTimeMillis();
    boolean result;
    long timeInMills = TimeUnit.MILLISECONDS.convert(time, unit);
    while (!(result = db.lockForWriting(names)) && System.currentTimeMillis() - start <= timeInMills) {
        //wait a bit (between 50 and 300 ms)
        long sleepDurationMillis = 50 + ThreadLocalRandom.current().nextInt(251);
        Thread.sleep(sleepDurationMillis);
    }
    return result;
}

private List<SampledResponseTime> createSampledResponseTimeList(TimeWindow timeWindow) {
    List<SampledResponseTime> sampledResponseTimeList = new ArrayList<>();
    int maxConnectionSize = ThreadLocalRandom.current().nextInt(MIN_VALUE_OF_MAX_CONNECTION_SIZE) + MIN_VALUE_OF_MAX_CONNECTION_SIZE;
    long from = timeWindow.getWindowRange().getFrom();
    long to = timeWindow.getWindowRange().getTo();
    for (long i = from; i < to; i += timeWindow.getWindowSlotSize()) {
        sampledResponseTimeList.add(createSampledResponseTime(i, maxConnectionSize));
    }
    return sampledResponseTimeList;
}

Runnable newEliminationStackRunner() {
    final EliminationStack<Integer> stack = new EliminationStack<>();
    return new Runnable() {

        @Override
        public void run() {
            final ThreadLocalRandom random = ThreadLocalRandom.current();
            for (; ; ) {
                if (random.nextBoolean()) {
                    stack.push(ELEMENT);
                } else {
                    stack.pop();
                }
                calls.increment();
            }
        }
    };
}

static String randomBirthday() {
    long minDay = LocalDate.of(1950, 1, 1).toEpochDay();
    long maxDay = LocalDate.of(2002, 12, 31).toEpochDay();
    long randomDay = ThreadLocalRandom.current().nextLong(minDay, maxDay);
    LocalDate randomDate = LocalDate.ofEpochDay(randomDay);
    DateTimeFormatter yearlyFormat = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    return randomDate.format(yearlyFormat);
}

private List<SampledResponseTime> createSampledResponseTimeList(TimeWindow timeWindow) {
    List<SampledResponseTime> sampledResponseTimeList = new ArrayList<>();
    int maxConnectionSize = ThreadLocalRandom.current().nextInt(MIN_VALUE_OF_MAX_CONNECTION_SIZE) + MIN_VALUE_OF_MAX_CONNECTION_SIZE;
    long from = timeWindow.getWindowRange().getFrom();
    long to = timeWindow.getWindowRange().getTo();
    for (long i = from; i < to; i += timeWindow.getWindowSlotSize()) {
        sampledResponseTimeList.add(createSampledResponseTime(i, maxConnectionSize));
    }
    return sampledResponseTimeList;
}

@Override
protected void transformInverse(int x, int y, float[] out) {
    // int angle = (int) (Math.random() * 255);
    // faster than Math.random
    int angle = ThreadLocalRandom.current().nextInt(255);
    // float distance = (float) Math.random();
    // faster than Math.random
    float distance = ThreadLocalRandom.current().nextFloat();
    out[0] = x + distance * sinTable[angle];
    out[1] = y + distance * cosTable[angle];
}

@Setup
public void preapre() {
    rands = new long[(DEPTH + 1) * 4];
    Random rnd = ThreadLocalRandom.current();
    for (int i = 0; i < rands.length; i++) rands[i] = rnd.nextLong();
    runnable = new Runnable() {

        @Override
        public void run() {
            res = recursive1(DEPTH);
        }
    };
    fiber = new Fiber((String) null, null, STACK, new SuspendableRunnable() {

        @Override
        public void run() throws SuspendExecution {
            res = recursive2(DEPTH);
        }
    });
    fiber2 = new Fiber((String) null, null, STACK, new SuspendableRunnable() {

        @Override
        public void run() throws SuspendExecution {
            res = recursive3(DEPTH);
        }
    });
}

/**
     * Generates a random String of hex characters. The requested String length must be even and must not exceed
     * {@link #MAX_RANDOM_STRING_LENGTH}. The {@link IdGeneratorType} parameter select between computationally cheap or cryptographically
     * secure random generation.
     * 
     * @param length the requested string length
     * @param generatorType whether to prioritize speed {@link IdGeneratorType#FAST} or security ( {@link IdGeneratorType#SECURE})
     * @return the generated string
     */
public static String createRandomHexString(int length, IdGeneratorType generatorType) {
    validateRequestedLength(length);
    byte[] bytes = new byte[length / 2];
    switch(generatorType) {
        case FAST:
            ThreadLocalRandom.current().nextBytes(bytes);
            break;
        case SECURE:
            sharedSecureRandom.nextBytes(bytes);
            break;
        default:
            throw new IllegalArgumentException();
    }
    String string = endodeBytesAsHexAndValidateLength(bytes, length);
    return string;
}

@Override
public void run() {
    for (int j = 0; j < loops; j++) {
        RLock lock = redisson.getLock("RLOCK_" + j);
        try {
            if (lock.tryLock(ThreadLocalRandom.current().nextInt(10), TimeUnit.MILLISECONDS)) {
                try {
                    RBucket<String> bucket = redisson.getBucket("RBUCKET_" + j);
                    bucket.set("TEST", 30, TimeUnit.SECONDS);
                    RSemaphore semaphore = redisson.getSemaphore("SEMAPHORE_" + j);
                    semaphore.release();
                    try {
                        semaphore.acquire();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                } finally {
                    lock.unlock();
                }
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public String discover() {
    String data = null;
    int size = dataList.size();
    if (size > 0) {
        if (size == 1) {
            data = dataList.get(0);
            Logger.debug("using only data: {}", data);
        } else {
            data = dataList.get(ThreadLocalRandom.current().nextInt(size));
            Logger.debug("using random data: {}", data);
        }
    }
    return data;
}

/**
     * Generate a random UUID v4 that will perform reasonably when used by
     * multiple threads under load.
     *
     * @see https://github.com/Netflix/netflix-commons/blob/v0.3.0/netflix-commons-util/src/main/java/com/netflix/util/concurrent/ConcurrentUUIDFactory.java
     * @return random UUID
     */
private static UUID generateRandomUuid() {
    final Random rnd = ThreadLocalRandom.current();
    long mostSig = rnd.nextLong();
    long leastSig = rnd.nextLong();
    // Identify this as a version 4 UUID, that is one based on a random value.
    mostSig &= 0xffffffffffff0fffL;
    mostSig |= 0x0000000000004000L;
    // Set the variant identifier as specified for version 4 UUID values.  The two
    // high order bits of the lower word are required to be one and zero, respectively.
    leastSig &= 0x3fffffffffffffffL;
    leastSig |= 0x8000000000000000L;
    return new UUID(mostSig, leastSig);
}

@Test
public void testGetPut() throws Exception {
    final PasswordFactory passwordFactory = PasswordFactory.getInstance(UnixMD5CryptPassword.ALGORITHM_CRYPT_MD5);
    byte[] b = new byte[16];
    ThreadLocalRandom.current().nextBytes(b);
    final Password password = passwordFactory.generatePassword(new EncryptablePasswordSpec("swordfish".toCharArray(), new SaltedPasswordAlgorithmSpec(b)));
    KeyStore keyStore = KeyStore.getInstance("PasswordFile");
    keyStore.load(new InputStream() {

        public int read() throws IOException {
            return -1;
        }
    }, null);
    keyStore.setEntry("bob", new PasswordEntry(password), null);
    final KeyStore.Entry entry = keyStore.getEntry("bob", null);
    assertNotNull("Missing entry", entry);
    assertTrue("Wrong entry type", entry instanceof PasswordEntry);
    final Password storedPassword = ((PasswordEntry) entry).getPassword();
    assertNotNull(storedPassword);
    assertSame(password, storedPassword);
}

@Test
public void testGetPut() throws Exception {
    final PasswordFactory passwordFactory = PasswordFactory.getInstance(UnixMD5CryptPassword.ALGORITHM_CRYPT_MD5);
    byte[] b = new byte[16];
    ThreadLocalRandom.current().nextBytes(b);
    final Password password = passwordFactory.generatePassword(new EncryptablePasswordSpec("swordfish".toCharArray(), new SaltedPasswordAlgorithmSpec(b)));
    KeyStore keyStore = KeyStore.getInstance("PasswordFile");
    keyStore.load(new InputStream() {

        public int read() throws IOException {
            return -1;
        }
    }, null);
    keyStore.setEntry("bob", new PasswordEntry(password), null);
    final KeyStore.Entry entry = keyStore.getEntry("bob", null);
    assertNotNull("Missing entry", entry);
    assertTrue("Wrong entry type", entry instanceof PasswordEntry);
    final Password storedPassword = ((PasswordEntry) entry).getPassword();
    assertNotNull(storedPassword);
    assertSame(password, storedPassword);
}

/**
   * Tests {@link CostBenefitInfo} for comparisons
   */
@Test
public void testCostBenefitInfoComparison() {
    List<String> randomSegments = CompactionPolicyTest.generateRandomStrings(3);
    long cost = getRandomCost();
    int benefit = 1 + TestUtils.RANDOM.nextInt(Integer.MAX_VALUE - 1);
    CostBenefitInfo one = new CostBenefitInfo(randomSegments, cost, benefit);
    // generate a CostBenefitInfo with cost = 1 + one's cost
    compareAndTest(one, 1, 0, -1);
    // generate a CostBenefitInfo with cost = 1 - one's cost
    compareAndTest(one, -1, 0, 1);
    // generate a CostBenefitInfo with same cost as one
    compareAndTest(one, 0, 0, 0);
    // generate a CostBenefitInfo with benefit = 1 + one's benefit
    compareAndTest(one, 0, 1, 1);
    // generate a CostBenefitInfo with benefit = 1 - one's benefit
    compareAndTest(one, 0, -1, -1);
    // test a case where costBenefitRatio is same, but diff cost and benefit.
    cost = ThreadLocalRandom.current().nextLong(Integer.MAX_VALUE / 2);
    benefit = 2 + TestUtils.RANDOM.nextInt(Integer.MAX_VALUE / 2 - 2);
    if (cost % 2 != 0) {
        cost++;
    }
    if (benefit % 2 != 0) {
        benefit++;
    }
    one = new CostBenefitInfo(randomSegments, cost, benefit);
    // generate a CostBenefitInfo with cost = half of one and benefit = half of one. CostBenefit is same, but one'e
    // benefit is more
    compareAndTest(one, (cost / 2) * (-1), (benefit / 2) * (-1), -1);
}

@Test
public void testConcurrentAccess() throws InterruptedException {
    SlidingWindowCounter counter = new SlidingWindowCounter(Ticker.systemTicker(), Duration.ofMinutes(5), Duration.ofMillis(1));
    int worker = 6;
    int batch = 100000;
    AtomicLong success = new AtomicLong();
    AtomicLong failure = new AtomicLong();
    CyclicBarrier barrier = new CyclicBarrier(worker);
    List<Thread> threads = new ArrayList<>(worker);
    for (int i = 0; i < worker; i++) {
        Thread t = new Thread(() -> {
            try {
                barrier.await();
                long s = 0;
                long f = 0;
                for (int j = 0; j < batch; j++) {
                    double r = ThreadLocalRandom.current().nextDouble();
                    if (r > 0.6) {
                        counter.onSuccess();
                        s++;
                    } else if (r > 0.2) {
                        counter.onFailure();
                        f++;
                    }
                }
                success.addAndGet(s);
                failure.addAndGet(f);
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
        threads.add(t);
        t.start();
    }
    for (Thread thread : threads) {
        thread.join();
    }
    await().untilAsserted(() -> assertThat(counter.onFailure()).isPresent());
    assertThat(counter.count()).isEqualTo(new EventCount(success.get(), failure.get()));
}

@Override
public void onMessage(MessageEvent event) throws Exception {
    if (botName.equals(event.getUser().getNick()) || Math.abs(ThreadLocalRandom.current().nextDouble()) >= BUTT_MESSAGE_RATIO) {
        return;
    }
    StringBuilder butted = new StringBuilder();
    if (buttifyMessage(event.getMessage(), butted)) {
        event.respondChannel(butted.toString());
    }
}

private static GeoLocationRequest getMockGeoLocation() {
    final int index = ThreadLocalRandom.current().nextInt(ALL_GEOLOCS.size());
    final GeoLocationRequest location = new GeoLocationRequest();
    final Pair<String, String> pair = ALL_GEOLOCS.get(index);
    location.setLatitude(pair.getKey());
    location.setLongitude(pair.getValue());
    location.setAccuracy("50");
    location.setTimestamp(String.valueOf(new Date().getTime()));
    return location;
}

@Test
public void greetingFrame() {
    final int version = 1;
    final String agent = "test-0.1-SNAPSHOT";
    final long id = ThreadLocalRandom.current().nextLong();
    final GreetingFrame frame = new GreetingFrame(version, agent, id);
    final GreetingFrame recodedFrame = recode(frame);
    assertEquals(recodedFrame.getVersion(), version);
    assertEquals(recodedFrame.getAgent(), agent);
    assertEquals(recodedFrame.getId(), id);
}

@Before
public void setup() {
    MockitoAnnotations.initMocks(this);
    doNothing().when(mockCallback).accept(any(MockFailure.class));
    ticker = new FakeTicker();
    ticker.advance(ThreadLocalRandom.current().nextLong());
    mockActor = TestProbe.apply(actorSystem);
    mockRequest = new MockRequest(mockIdentifier, mockReplyTo);
    mockResponse = mockRequest.toRequestFailure(mockCause);
    entry = new ConnectionEntry(mockRequest, mockCallback, ticker.read());
}

@Listener
public void onPlayerInteract(InteractBlockEvent.Secondary.MainHand event, @Named(NamedCause.SOURCE) Player player) {
    event.getTargetBlock().getLocation().filter((this::isValid)).ifPresent( location -> {
        if (!sneakState.getValue().doesPass(player.get(Keys.IS_SNEAKING).orElse(false) || !usePermissions.hasPermission(player))) {
            return;
        }
        if (!readWhenHoldingBlock.getValue()) {
            ItemStack stack = player.getItemInHand(HandTypes.MAIN_HAND).filter(( itemStack -> itemStack.getItem().getBlock().isPresent())).orElse(null);
            if (stack != null)
                return;
        }
        String line = bookLines[ThreadLocalRandom.current().nextInt(bookLines.length)];
        player.sendMessage(Text.of(TextColors.YELLOW, "You pick up a book..."));
        player.sendMessage(Text.of(line));
    });
}

@Test
public void shouldUploadFileForNonExistingRepresentation() {
    //given
    String providerId = "providerId";
    byte[] content = new byte[1000];
    ThreadLocalRandom.current().nextBytes(content);
    String contentMd5 = Hashing.md5().hashBytes(content).toString();
    FormDataMultiPart multipart = new FormDataMultiPart().field(ParamConstants.F_PROVIDER, providerId).field(ParamConstants.F_FILE_MIME, file.getMimeType()).field(ParamConstants.F_FILE_DATA, new ByteArrayInputStream(content), MediaType.APPLICATION_OCTET_STREAM_TYPE).field(ParamConstants.F_FILE_NAME, file.getFileName());
    //when
    Response uploadFileResponse = fileWebTarget.request().post(Entity.entity(multipart, multipart.getMediaType()));
    //then
    assertThat("Unexpected status code", uploadFileResponse.getStatus(), is(201));
    assertThat("File content tag does not match", uploadFileResponse.getEntityTag().getValue(), is(contentMd5));
}

/**
   * Starts an instance of DataNode with NN mocked. Called should ensure to
   * shutdown the DN
   *
   * @throws IOException
   */
public static DataNode startDNWithMockNN(Configuration conf, final InetSocketAddress nnSocketAddr, final String dnDataDir) throws IOException {
    FileSystem.setDefaultUri(conf, "hdfs://" + nnSocketAddr.getHostName() + ":" + nnSocketAddr.getPort());
    ArrayList<StorageLocation> locations = new ArrayList<StorageLocation>();
    File dataDir = new File(dnDataDir);
    FileUtil.fullyDelete(dataDir);
    dataDir.mkdirs();
    StorageLocation location = StorageLocation.parse(dataDir.getPath());
    locations.add(location);
    final DatanodeProtocolClientSideTranslatorPB namenode = mock(DatanodeProtocolClientSideTranslatorPB.class);
    Mockito.doAnswer(new Answer<DatanodeRegistration>() {

        @Override
        public DatanodeRegistration answer(InvocationOnMock invocation) throws Throwable {
            return (DatanodeRegistration) invocation.getArguments()[0];
        }
    }).when(namenode).registerDatanode(Mockito.any(DatanodeRegistration.class));
    when(namenode.versionRequest()).thenReturn(new NamespaceInfo(1, TEST_CLUSTER_ID, TEST_POOL_ID, 1L));
    when(namenode.sendHeartbeat(Mockito.any(DatanodeRegistration.class), Mockito.any(StorageReport[].class), Mockito.anyLong(), Mockito.anyLong(), Mockito.anyInt(), Mockito.anyInt(), Mockito.anyInt(), Mockito.any(VolumeFailureSummary.class), Mockito.anyBoolean(), Mockito.any(SlowPeerReports.class))).thenReturn(new HeartbeatResponse(new DatanodeCommand[0], new NNHAStatusHeartbeat(HAServiceState.ACTIVE, 1), null, ThreadLocalRandom.current().nextLong() | 1L));
    DataNode dn = new DataNode(conf, locations, null, null) {

        @Override
        DatanodeProtocolClientSideTranslatorPB connectToNN(InetSocketAddress nnAddr) throws IOException {
            Assert.assertEquals(nnSocketAddr, nnAddr);
            return namenode;
        }
    };
    // Trigger a heartbeat so that it acknowledges the NN as active.
    dn.getAllBpOs()[0].triggerHeartbeatForTests();
    return dn;
}

@Test
@Repeating(repetition = 10)
public void testSeconds() {
    // just 1 VInt
    long seconds = ThreadLocalRandom.current().nextLong(Integer.MAX_VALUE);
    TimestampTZ tstz = new TimestampTZ(seconds, 0);
    verifyConversion(tstz);
    // 2 VInt
    seconds = ThreadLocalRandom.current().nextLong(Integer.MAX_VALUE) + Integer.MAX_VALUE + 1;
    if (ThreadLocalRandom.current().nextBoolean()) {
        seconds = -seconds;
    }
    tstz.set(seconds, 0);
    verifyConversion(tstz);
}

public byte[] sign(Messages.LogMessage message) {
    try {
        final MessageDigest digest = MessageDigest.getInstance("SHA-256");
        final byte[] hash = digest.digest(message.getMessage().toByteArray());
        final byte[] iv = new byte[BLOCK_SIZE];
        ThreadLocalRandom.current().nextBytes(iv);
        final Cipher cipher = createCipher(Cipher.ENCRYPT_MODE, iv);
        byte[] cipherText = cipher.doFinal(pad(hash));
        byte[] signature = new byte[iv.length + cipherText.length];
        System.arraycopy(iv, 0, signature, 0, iv.length);
        System.arraycopy(cipherText, 0, signature, iv.length, cipherText.length);
        return signature;
    } catch (GeneralSecurityException e) {
        throw new LoggregatorException(e);
    }
}

@Override
public Object filter(Object object, JinjavaInterpreter interpreter, String... arg) {
    if (object == null) {
        return null;
    }
    // collection
    if (object instanceof Collection) {
        Collection<?> clt = (Collection<?>) object;
        Iterator<?> it = clt.iterator();
        int size = clt.size();
        if (size == 0) {
            return null;
        }
        int index = ThreadLocalRandom.current().nextInt(size);
        while (index-- > 0) {
            it.next();
        }
        return it.next();
    }
    // array
    if (object.getClass().isArray()) {
        int size = Array.getLength(object);
        if (size == 0) {
            return null;
        }
        int index = ThreadLocalRandom.current().nextInt(size);
        return Array.get(object, index);
    }
    // map
    if (object instanceof Map) {
        Map<?, ?> map = (Map<?, ?>) object;
        Iterator<?> it = map.values().iterator();
        int size = map.size();
        if (size == 0) {
            return null;
        }
        int index = ThreadLocalRandom.current().nextInt(size);
        while (index-- > 0) {
            it.next();
        }
        return it.next();
    }
    // number
    if (object instanceof Number) {
        return ThreadLocalRandom.current().nextLong(((Number) object).longValue());
    }
    // string
    if (object instanceof String) {
        try {
            return ThreadLocalRandom.current().nextLong(new BigDecimal((String) object).longValue());
        } catch (Exception e) {
            return 0;
        }
    }
    return object;
}

/** {@inheritDoc} */
@Override
public String execute(SampleResult previousResult, Sampler currentSampler) throws InvalidVariableException {
    long min = Long.parseLong(minimum.execute().trim());
    long max = Long.parseLong(maximum.execute().trim());
    long rand = ThreadLocalRandom.current().nextLong(min, max + 1);
    String randString = Long.toString(rand);
    if (varName != null) {
        JMeterVariables vars = getVariables();
        final String varTrim = varName.execute().trim();
        if (vars != null && varTrim.length() > 0) {
            // vars will be null on TestPlan
            vars.put(varTrim, randString);
        }
    }
    return randString;
}

private int nextValue(String topic) {
    AtomicInteger counter = topicCounterMap.get(topic);
    if (null == counter) {
        counter = new AtomicInteger(ThreadLocalRandom.current().nextInt());
        AtomicInteger currentCounter = topicCounterMap.putIfAbsent(topic, counter);
        if (currentCounter != null) {
            counter = currentCounter;
        }
    }
    return counter.getAndIncrement();
}

private long getSleepTime(int retryCount) {
    if (retryCount < retriesLimit) {
        long low = baseSleepTimeNanos * (1L << retryCount);
        long high = 2 * low;
        long sleepTimeNanos = ThreadLocalRandom.current().nextLong(low, high);
        return Math.min(maxSleepTimeNanos, sleepTimeNanos);
    } else {
        return maxSleepTimeNanos;
    }
}

public static <S extends Sequence<S>> void assertRA(List<FastaRecord<S>> seqs, Path path, Alphabet<S> alphabet, boolean allowReverse) throws Exception {
    try (RandomAccessFastaReader<S> raReader = new RandomAccessFastaReader<>(path, alphabet)) {
        ThreadLocalRandom r = ThreadLocalRandom.current();
        for (int i = 0; i < 1000; i++) {
            FastaRecord<S> rec = seqs.get(r.nextInt(seqs.size()));
            int from = r.nextInt(rec.getSequence().size() - 1);
            int to = allowReverse ? r.nextInt(rec.getSequence().size() - 1) : r.nextInt(from, rec.getSequence().size());
            Range range = new Range(from, to);
            Assert.assertEquals(rec.getSequence().getRange(range), raReader.getSequence((int) rec.getId(), range));
            Assert.assertEquals(rec.getSequence().getRange(range), raReader.getSequence(rec.getDescription(), range));
        }
    }
}

@Override
public void run() {
    ForwardingObjective forwardingObjective = DefaultForwardingObjective.builder().withSelector(FlowPusherTask.this.selectorBuilder.build()).withTreatment(FlowPusherTask.this.treatment).withPriority(ThreadLocalRandom.current().nextInt(100, 4000 + 1)).withFlag(ForwardingObjective.Flag.VERSATILE).fromApp(FlowPusherTask.this.appId).makeTemporary(/*.makePermanent()*/
    ThreadLocalRandom.current().nextInt(100, 4000 + 1)).add(new TimerObjectiveContext());
    //FlowRuleOperations operations = builder.build(flowRuleOperationsContext);
    //flowRuleService.apply(operations);
    log.info("Starting the Flowpusher task for " + FlowPusherTask.this.appId.name() + " on device " + FlowPusherTask.this.device.id() + "with id => " + forwardingObjective.id());
    flowObjectiveService.forward(FlowPusherTask.this.device.id(), forwardingObjective);
}

@Benchmark
public Statement createAndLeak() throws SQLException {
    Statement statement = connection.createStatement();
    Random rnd;
    //#if mvn.project.property.current.jdk < "1.7"
    rnd = random;
    //#else
    rnd = java.util.concurrent.ThreadLocalRandom.current();
    //#endif
    if (rnd.nextFloat() >= leakPctFloat) {
        statement.close();
    }
    return statement;
}

@Test
public void testOneOfTwoInstancesCrashing() throws Exception {
    // Build node 1
    HazelcastInstance hazelcast1 = createHazelcastInstance("testOneOfTwoInstancesCrashing");
    HazelcastJobStore.setHazelcastClient(hazelcast1);
    HazelcastJobStore jobstore1 = createJobStore("jobstore1");
    jobstore1.setTriggerReleaseThreshold(450);
    jobstore1.setShutdownHazelcastOnShutdown(false);
    jobstore1.initialize(null, new SampleSignaler());
    // Build node 2
    HazelcastInstance hazelcast2 = createHazelcastInstance("testOneOfTwoInstancesCrashing");
    HazelcastJobStore.setHazelcastClient(hazelcast2);
    HazelcastJobStore jobstore2 = createJobStore("jobstore2");
    jobstore2.setShutdownHazelcastOnShutdown(false);
    jobstore2.setTriggerReleaseThreshold(450);
    jobstore2.initialize(null, new SampleSignaler());
    // Add a job and its trigger to the scheduler
    JobDetail job = JobBuilder.newJob(TestSlowJob.class).withIdentity("job1", "jobGroup1").build();
    OperableTrigger trigger = buildAndComputeTrigger("trigger1", "triggerGroup1", job, new Date().getTime());
    trigger.setMisfireInstruction(MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICY);
    jobstore1.storeJobAndTrigger(job, (OperableTrigger) trigger);
    long firstFireTime = new Date(trigger.getNextFireTime().getTime()).getTime();
    // Create a thread for acquiring next triggers on node 1
    Thread acquireThread = new Thread(() -> {
        try {
            List<OperableTrigger> triggers1 = jobstore1.acquireNextTriggers(firstFireTime + 150, 1, 0L);
            triggers1.forEach(jobstore1::releaseAcquiredTrigger);
        } catch (JobPersistenceException e) {
            throw new RuntimeException(e);
        }
    }, "acquireThread");
    // Create a thread for terminating Hazelcast on node 1
    Thread terminateThread = new Thread(hazelcast1.getLifecycleService()::terminate, "terminateThread");
    // Start acquiring next triggers and right after start terminating Hazelcast
    acquireThread.start();
    long waitTime = ThreadLocalRandom.current().nextInt(1, 51);
    Thread.sleep(waitTime);
    terminateThread.start();
    // Wait a bit
    Thread.sleep(500);
    // Acquire next triggers on node 2, we should get our trigger here!
    List<OperableTrigger> triggers2 = jobstore2.acquireNextTriggers(firstFireTime + 150 + 6000, 10, 0L);
    System.err.println("-------------------------> VAL " + triggers2.size());
    assertEquals(triggers2.size(), 1, "Should find 1 trigger on node 2 after node 1 crashed when failing after " + waitTime + "ms");
}

@Override
public void run() {
    Timer.Context context = metrics.totalReadTime.time();
    Stopwatch stopwatch = new Stopwatch().start();
    try {
        log.info("Running metrics queries");
        ThreadLocalRandom random = ThreadLocalRandom.current();
        int bound = startingSchedule + batchSize;
        findResourceDataForPast24Hours(random.nextInt(startingSchedule, bound));
        findResourceDataForPastWeek(random.nextInt(startingSchedule, bound));
        findResourceDataForPast2Weeks(random.nextInt(startingSchedule, bound));
        findResourceDataForPast31Days(random.nextInt(startingSchedule, bound));
        findResourceDataForPastYear(random.nextInt(startingSchedule, bound));
    } finally {
        stopwatch.stop();
        log.info("Finished running metrics queries in " + stopwatch.elapsed(TimeUnit.MILLISECONDS) + " ms");
        context.stop();
    }
}

@Override
public Observable<Connection<R, W>> newConnectionRequest() {
    HostHolder<W, R> selected = null;
    if (hosts.isEmpty()) {
        noUsableHostsFound();
        return Observable.error(NoHostsAvailableException.EMPTY_INSTANCE);
    } else if (hosts.size() == 1) {
        HostHolder<W, R> holder = hosts.get(0);
        @SuppressWarnings("unchecked") L eventListener = (L) holder.getEventListener();
        double weight = getWeight(eventListener);
        if (isUnusable(weight)) {
            noUsableHostsFound();
            return Observable.error(new NoHostsAvailableException("No usable hosts found."));
        }
        selected = holder;
    } else {
        ThreadLocalRandom rand = ThreadLocalRandom.current();
        for (int i = 0; i < 5; i++) {
            int pos = rand.nextInt(hosts.size());
            HostHolder<W, R> first = hosts.get(pos);
            int pos2 = (rand.nextInt(hosts.size() - 1) + pos + 1) % hosts.size();
            HostHolder<W, R> second = hosts.get(pos2);
            @SuppressWarnings("unchecked") double w1 = getWeight((L) first.getEventListener());
            @SuppressWarnings("unchecked") double w2 = getWeight((L) second.getEventListener());
            if (w1 > w2) {
                selected = first;
                break;
            } else if (w1 < w2) {
                selected = second;
                break;
            } else if (!isUnusable(w1)) {
                selected = first;
                break;
            }
            foundTwoUnusableHosts();
        }
        if (null == selected) {
            noUsableHostsFound();
            return Observable.error(new NoHostsAvailableException("No usable hosts found after 5 tries."));
        }
    }
    return selected.getConnector().getConnectionProvider().newConnectionRequest();
}

@Test
public void testRandomInt() {
    for (int i = 0; i < NR_RANDOM_NUMBERS; i++) {
        byte[] bytes = new byte[1];
        ThreadLocalRandom.current().nextBytes(bytes);
        byte nextByte = bytes[0];
        assertEquals(nextByte, LLVM80BitFloat.fromShort(nextByte).getShortValue());
        assertEquals(nextByte, LLVM80BitFloat.fromShort(nextByte).getShortValue());
    }
}

@Setup
public void setUp() {
    random = ThreadLocalRandom.current();
    tdigest = tdigestFactory.create(compression);
    distribution = distributionFactory.create(random);
    // first values are cheap to add, so pre-fill the t-digest to have more realistic results
    for (int i = 0; i < 10000; ++i) {
        tdigest.add(distribution.nextDouble());
    }
    for (int i = 0; i < data.length; ++i) {
        data[i] = distribution.nextDouble();
    }
}

public static void main(final String... args) throws IOException {
    final String project = Util.defaultProject();
    GoogleCredential credential;
    // Use credentials from file if available
    try {
        credential = GoogleCredential.fromStream(new FileInputStream("credentials.json")).createScoped(PubsubScopes.all());
    } catch (IOException e) {
        credential = GoogleCredential.getApplicationDefault().createScoped(PubsubScopes.all());
    }
    final Pubsub pubsub = Pubsub.builder().credential(credential).compressionLevel(Deflater.BEST_SPEED).enabledCipherSuites(nonGcmCiphers()).build();
    final Publisher publisher = Publisher.builder().pubsub(pubsub).concurrency(128).project(project).build();
    LoggingConfigurator.configureDefaults("benchmark", WARN);
    final String topicPrefix = TEST_NAME_PREFIX + ThreadLocalRandom.current().nextInt();
    final List<String> topics = IntStream.range(0, 100).mapToObj( i -> topicPrefix + "-" + i).collect(toList());
    topics.stream().map( topic -> pubsub.createTopic(project, topic)).collect(toList()).forEach(Futures::getUnchecked);
    final List<Message> messages = IntStream.range(0, 1000).mapToObj( i -> {
        final StringBuilder s = new StringBuilder();
        while (s.length() < MESSAGE_SIZE) {
            s.append(ThreadLocalRandom.current().nextInt());
        }
        return Message.ofEncoded(s.toString());
    }).collect(toList());
    final ProgressMeter meter = new ProgressMeter();
    final ProgressMeter.Metric requests = meter.group("operations").metric("publishes", "messages");
    for (int i = 0; i < 100000; i++) {
        benchSend(publisher, messages, topics, requests);
    }
}

private GitInfo buildGitInfo(String uri) {
    GitInfo gitInfo = GitInfo.fromString(uri);
    return new GitInfo(Optional.absent(), gitInfo.getHost(), gitInfo.getOrganization(), gitInfo.getRepository(), ThreadLocalRandom.current().nextInt(1337, 100000), gitInfo.getBranch(), true, System.currentTimeMillis(), System.currentTimeMillis());
}

@Before
public void setUp() throws Exception {
    // generate unique sandbox for this test
    File sandbox;
    do {
        currSandbox = SANDBOX_DIR + "sandbox" + Integer.toString(ThreadLocalRandom.current().nextInt(Integer.MAX_VALUE));
        sandbox = new File(currSandbox);
    } while (sandbox.exists());
    mavenSandbox = new FileSystemMavenSandbox(currSandbox);
    mojo = new GitCommitIdMojo();
    initializeMojoWithDefaults(mojo);
}

@Override
public void run() {
    int id = index.getAndIncrement();
    for (Integer e : sets.get(id)) {
        BiConsumer<A, Integer> operation = operations.get(ThreadLocalRandom.current().nextInt(operations.size()));
        try {
            operation.accept(collection, e);
        } catch (Throwable t) {
            failures.add(String.format("Failed: key %s on operation %s%n%s", e, operation, Throwables.getStackTraceAsString(t)));
            throw t;
        }
    }
}

@Override
public void setImportMetadata(AnnotationMetadata importMetadata) {
    final MultiValueMap<String, Object> attributes = importMetadata.getAllAnnotationAttributes(CfComponent.class.getName());
    type = evaluate(attributes, "type");
    index = Integer.valueOf(evaluate(attributes, "index"));
    uuid = evaluate(attributes, "uuid");
    if (StringUtils.isEmpty(uuid)) {
        uuid = UUID.randomUUID().toString();
    }
    host = evaluate(attributes, "host");
    port = Integer.valueOf(evaluate(attributes, "port"));
    username = evaluate(attributes, "username");
    password = evaluate(attributes, "password");
    if (StringUtils.isEmpty(password)) {
        password = new BigInteger(256, ThreadLocalRandom.current()).toString(32);
    }
}

public static void main(String[] args) {
    final String url = "jdbc:oracle:thin:@[SERVER]:1521/[SID]";
    final Properties props = new Properties();
    props.setProperty("user", "user");
    props.setProperty("password", "pwd");
    Connection conn = null;
    PreparedStatement stmt = null;
    ResultSet res = null;
    try {
        conn = DriverManager.getConnection(url, props);
        conn.setAutoCommit(false);
        stmt = conn.prepareStatement("select count(*) c from dba_tables where table_name = 'USR' and owner = 'SCHEMA'");
        res = stmt.executeQuery();
        res.next();
        if (res.getInt(1) != 1) {
            System.out.println("Table not found");
            stmt = conn.prepareStatement("create table usr(field NUMBER(11,0),v NUMBER(11,0), s VARCHAR2(1024))");
            stmt.execute();
            stmt = conn.prepareStatement("insert into usr(field,s) select rownum r,DBMS_RANDOM.STRING('U',1024) from dual connect by rownum <= 10000");
            stmt.execute();
            stmt = conn.prepareStatement("alter table usr add primary key (field)");
            stmt.execute();
            conn.commit();
            System.out.println("Table created");
        }
        ExecutorService service = Executors.newFixedThreadPool(MAX_SESSIONS);
        int sessionCount = 0;
        int field = 1;
        while (sessionCount < MAX_SESSIONS) {
            final int fieldVal = field;
            service.submit(new Runnable() {

                @Override
                public void run() {
                    Connection c = null;
                    PreparedStatement s = null;
                    ResultSet r = null;
                    try {
                        c = DriverManager.getConnection(url, props);
                        c.setAutoCommit(false);
                        String pid = String.valueOf(getPid(c));
                        System.out.println("[" + pid + "] Submited root session for " + String.valueOf(fieldVal));
                        s = c.prepareStatement("/*ROOT " + String.valueOf(fieldVal) + " */ update usr set v = 100500 where field = ?");
                        s.setInt(1, fieldVal);
                        s.executeUpdate();
                        while (true) {
                            try {
                                Thread.sleep(600 * 1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                                break;
                            }
                        }
                        c.close();
                    } catch (SQLException e) {
                        e.printStackTrace();
                        return;
                    }
                }
            });
            sessionCount++;
            if ((MAX_SESSIONS - sessionCount) > MIN_CHAIN_SIZE) {
                int chainCount = ThreadLocalRandom.current().nextInt(MIN_CHAIN_SIZE, MAX_CHAIN_SIZE + 1);
                if ((MAX_SESSIONS - sessionCount) >= chainCount) {
                    for (int i = 0; i < chainCount; i++) {
                        final int level = i;
                        int levelCount = ThreadLocalRandom.current().nextInt(1, MAX_LEVEL_ITEMS + 1);
                        for (int j = 0; j < levelCount; j++) {
                            final int levelNo = j;
                            service.submit(new Runnable() {

                                @Override
                                public void run() {
                                    try {
                                        Thread.sleep(5000);
                                    } catch (InterruptedException e1) {
                                        e1.printStackTrace();
                                    }
                                    Connection c = null;
                                    PreparedStatement s = null;
                                    ResultSet r = null;
                                    try {
                                        c = DriverManager.getConnection(url, props);
                                        c.setAutoCommit(false);
                                        int pid = getPid(c);
                                        String prefix;
                                        if (levelNo > 0) {
                                            int sublock = MAX_SESSIONS + (level * MAX_CHAIN_SIZE);
                                            prefix = String.format("[%d] Sublock %d for %d -> %d (%d) ", pid, sublock, fieldVal, level, levelNo);
                                            s = c.prepareStatement("/*" + prefix + "*/ update usr set v = 100500 where field = ?");
                                            System.out.println("Sublock for " + prefix);
                                            s.setInt(1, sublock);
                                            s.executeUpdate();
                                        }
                                        prefix = String.format("[%d] %d->%d (%d) ", pid, fieldVal, level, levelNo);
                                        s = c.prepareStatement("/*" + prefix + "*/ update usr set v = 100500 where field = ?");
                                        s.setInt(1, fieldVal);
                                        System.out.println("Wait session for " + prefix);
                                        s.executeUpdate();
                                        c.close();
                                    } catch (SQLException e) {
                                        e.printStackTrace();
                                        return;
                                    }
                                }
                            });
                            sessionCount++;
                            if (sessionCount >= MAX_SESSIONS) {
                                break;
                            }
                        }
                        if (sessionCount >= MAX_SESSIONS) {
                            break;
                        }
                    }
                }
            }
            field++;
        }
        System.out.println("Sbmited " + sessionCount);
        service.shutdown();
        service.awaitTermination(1, TimeUnit.HOURS);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void run() {
    long randomWaitDiff = ThreadLocalRandom.current().nextLong((MAX_POLL_SEC / 2) * 1_000L);
    while (true) {
        try {
            // random so not everybody executes simultaneously
            Thread.sleep((MAX_POLL_SEC / 2) * 1_000L + randomWaitDiff);
        } catch (InterruptedException e) {
            return;
        }
        Map<Long, Set<Ticket>> timeoutedTickets = timeouts.headMap(System.currentTimeMillis() - TicketValidityService.CLEANUP_NO_REMOVE_MOST_RECENT_MS);
        if (!timeoutedTickets.isEmpty()) {
            logger.info("Found {} tickets that have been logged out but are invalid now anyway. " + "Removing them from the consensus cluster.", timeoutedTickets.size());
            try (ClosableProvider<LogoutStateMachine> p = consensusClient.getStateMachineClient(LogoutStateMachine.class)) {
                Set<Ticket> allTickets = timeoutedTickets.values().stream().flatMap( s -> s.stream()).collect(Collectors.toSet());
                for (Ticket t : allTickets) p.getClient().cleanLogoutTicket(CleanLogoutTicket.local(t));
                timeoutedTickets.clear();
            } catch (ConsensusClusterUnavailableException e) {
                logger.warn("Could not contact consensus cluster to remove old logged out tickets.", e);
            } catch (ConsensusStateMachineClientInterruptedException e) {
                return;
            } catch (RuntimeException e) {
                logger.warn("Could not contact consensus cluster to remove old logged out tickets", e);
            }
        }
    }
}

/**
   * Helper method to generate QueryId
   * @return generated QueryId
   */
private static QueryId queryIdGenerator() {
    ThreadLocalRandom r = ThreadLocalRandom.current();
    // create a new queryid where the first four bytes are a growing time (each new value comes earlier in sequence).  Last 12 bytes are random.
    final long time = (int) (System.currentTimeMillis() / 1000);
    final long p1 = ((Integer.MAX_VALUE - time) << 32) + r.nextInt();
    final long p2 = r.nextLong();
    final QueryId id = QueryId.newBuilder().setPart1(p1).setPart2(p2).build();
    return id;
}

@Override
public void run() {
    try {
        barrier.await();
        long x = ThreadLocalRandom.current().nextInt();
        long y = ThreadLocalRandom.current().nextInt();
        long addition = x + y;
        Map<String, Object> vars = new HashMap<String, Object>();
        vars.put("x", x);
        vars.put("y", y);
        ExecutableScript script = se.executable(compiled, vars);
        for (int i = 0; i < 100000; i++) {
            long result = ((Number) script.run()).longValue();
            assertThat(result, equalTo(addition));
        }
    } catch (Throwable t) {
        failed.set(true);
        logger.error("failed", t);
    } finally {
        latch.countDown();
    }
}

@Override
public void run() {
    try {
        barrier.await();
        long x = ThreadLocalRandom.current().nextInt();
        long y = ThreadLocalRandom.current().nextInt();
        long addition = x + y;
        Map<String, Object> vars = new HashMap<String, Object>();
        vars.put("x", x);
        vars.put("y", y);
        ExecutableScript script = se.executable(compiled, vars);
        for (int i = 0; i < 100000; i++) {
            long result = ((Number) script.run()).longValue();
            assertThat(result, equalTo(addition));
        }
    } catch (Throwable t) {
        failed.set(true);
        logger.error("failed", t);
    } finally {
        latch.countDown();
    }
}

/**
   * Test to verify the processing of PendingDataNodeMessageQueue in case of
   * append. One block will marked as corrupt if the OP_ADD, OP_UPDATE_BLOCKS
   * comes in one edit log segment and OP_CLOSE edit comes in next log segment
   * which is loaded during failover. Regression test for HDFS-3605.
   */
@Test
public void testMultipleAppendsDuringCatchupTailing() throws Exception {
    Configuration conf = new Configuration();
    // Set a length edits tailing period, and explicit rolling, so we can
    // control the ingest of edits by the standby for this test.
    conf.set(DFSConfigKeys.DFS_HA_TAILEDITS_PERIOD_KEY, "5000");
    conf.setInt(DFSConfigKeys.DFS_HA_LOGROLL_PERIOD_KEY, -1);
    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).nnTopology(MiniDFSNNTopology.simpleHATopology()).numDataNodes(3).build();
    FileSystem fs = null;
    try {
        cluster.transitionToActive(0);
        fs = HATestUtil.configureFailoverFs(cluster, conf);
        Path fileToAppend = new Path("/FileToAppend");
        Path fileToTruncate = new Path("/FileToTruncate");
        final byte[] data = new byte[1 << 16];
        ThreadLocalRandom.current().nextBytes(data);
        final int[] appendPos = AppendTestUtil.randomFilePartition(data.length, COUNT);
        final int[] truncatePos = AppendTestUtil.randomFilePartition(data.length, 1);
        // Create file, write some data, and hflush so that the first
        // block is in the edit log prior to roll.
        FSDataOutputStream out = createAndHflush(fs, fileToAppend, data, appendPos[0]);
        FSDataOutputStream out4Truncate = createAndHflush(fs, fileToTruncate, data, data.length);
        // Let the StandbyNode catch the creation of the file. 
        cluster.getNameNode(0).getRpcServer().rollEditLog();
        cluster.getNameNode(1).getNamesystem().getEditLogTailer().doTailEdits();
        out.close();
        out4Truncate.close();
        // Append and re-close a few time, so that many block entries are queued.
        for (int i = 0; i < COUNT; i++) {
            int end = i < COUNT - 1 ? appendPos[i + 1] : data.length;
            out = fs.append(fileToAppend);
            out.write(data, appendPos[i], end - appendPos[i]);
            out.close();
        }
        boolean isTruncateReady = fs.truncate(fileToTruncate, truncatePos[0]);
        // Ensure that blocks have been reported to the SBN ahead of the edits
        // arriving.
        cluster.triggerBlockReports();
        // Failover the current standby to active.
        cluster.shutdownNameNode(0);
        cluster.transitionToActive(1);
        // Check the FSCK doesn't detect any bad blocks on the SBN.
        int rc = ToolRunner.run(new DFSck(cluster.getConfiguration(1)), new String[] { "/", "-files", "-blocks" });
        assertEquals(0, rc);
        assertEquals("CorruptBlocks should be empty.", 0, cluster.getNameNode(1).getNamesystem().getCorruptReplicaBlocks());
        AppendTestUtil.checkFullFile(fs, fileToAppend, data.length, data, fileToAppend.toString());
        if (!isTruncateReady) {
            TestFileTruncate.checkBlockRecovery(fileToTruncate, cluster.getFileSystem(1));
        }
        AppendTestUtil.checkFullFile(fs, fileToTruncate, truncatePos[0], data, fileToTruncate.toString());
    } finally {
        if (null != cluster) {
            cluster.shutdown();
        }
        if (null != fs) {
            fs.close();
        }
    }
}

@Test
public void testCreateSearchIndexValidationBusinessObjectDefinitions() {
    // Create a search index key.
    SearchIndexKey searchIndexKey = new SearchIndexKey(SEARCH_INDEX_NAME);
    // Get the search index type value.
    String searchIndexType = SearchIndexTypeEntity.SearchIndexTypes.BUS_OBJCT_DFNTN.name();
    // Create a search index create request.
    SearchIndexValidationCreateRequest searchIndexValidationCreateRequest = new SearchIndexValidationCreateRequest(searchIndexKey);
    //Create the search index type entity
    SearchIndexTypeEntity searchIndexTypeEntity = new SearchIndexTypeEntity();
    searchIndexTypeEntity.setCode(searchIndexType);
    //Create a search index entity
    SearchIndexEntity searchIndexEntity = new SearchIndexEntity();
    searchIndexEntity.setName(SEARCH_INDEX_NAME);
    searchIndexEntity.setType(searchIndexTypeEntity);
    //validation response
    boolean sizeCheck = ThreadLocalRandom.current().nextDouble() < 0.5;
    boolean spotCheckPercentage = ThreadLocalRandom.current().nextDouble() < 0.5;
    boolean spotCheckMostRecent = ThreadLocalRandom.current().nextDouble() < 0.5;
    // Mock some of the external call responses.
    @SuppressWarnings("unchecked") Future<Void> mockedFuture = mock(Future.class);
    // Mock the external calls.
    when(alternateKeyHelper.validateStringParameter("Search index name", SEARCH_INDEX_NAME)).thenReturn(SEARCH_INDEX_NAME);
    when(searchIndexDaoHelper.getSearchIndexEntity(searchIndexKey)).thenReturn(searchIndexEntity);
    when(businessObjectDefinitionService.indexValidateAllBusinessObjectDefinitions()).thenReturn(new AsyncResult<>(null));
    when(businessObjectDefinitionService.indexSizeCheckValidationBusinessObjectDefinitions()).thenReturn(sizeCheck);
    when(businessObjectDefinitionService.indexSpotCheckPercentageValidationBusinessObjectDefinitions()).thenReturn(spotCheckPercentage);
    when(businessObjectDefinitionService.indexSpotCheckMostRecentValidationBusinessObjectDefinitions()).thenReturn(spotCheckMostRecent);
    // Create a search index.
    SearchIndexValidation response = searchIndexValidationService.createSearchIndexValidation(searchIndexValidationCreateRequest);
    // Verify the external calls.
    verify(alternateKeyHelper).validateStringParameter("Search index name", SEARCH_INDEX_NAME);
    verify(businessObjectDefinitionService, times(1)).indexValidateAllBusinessObjectDefinitions();
    verify(searchIndexDaoHelper).getSearchIndexEntity(searchIndexKey);
    verify(businessObjectDefinitionService).indexValidateAllBusinessObjectDefinitions();
    verify(businessObjectDefinitionService).indexSizeCheckValidationBusinessObjectDefinitions();
    verify(businessObjectDefinitionService).indexSpotCheckPercentageValidationBusinessObjectDefinitions();
    verify(businessObjectDefinitionService).indexSpotCheckMostRecentValidationBusinessObjectDefinitions();
    verifyNoMoreInteractions(alternateKeyHelper, searchIndexDaoHelper, businessObjectDefinitionService);
    // Validate the returned object.
    assertEquals(new SearchIndexValidation(searchIndexKey, response.getValidateStartTime(), sizeCheck, spotCheckPercentage, spotCheckMostRecent), response);
}

@Override
public E poll() {
    Queue<E>[] qs = this.queues;
    final int start = ThreadLocalRandom.current().nextInt(qs.length);
    for (int i = start; i < qs.length; i++) {
        E e = qs[i].poll();
        if (e != null)
            return e;
    }
    for (int i = 0; i < start; i++) {
        E e = qs[i].poll();
        if (e != null)
            return e;
    }
    return null;
}

void doTest(String[] args) throws Throwable {
    final int n = ThreadLocalRandom.current().nextInt(1, 10);
    final Phaser startingGate = new Phaser(n);
    final Phaser phaser = new Phaser(n);
    final List<Thread> threads = new ArrayList<Thread>();
    final AtomicInteger count0 = new AtomicInteger(0);
    final AtomicInteger count1 = new AtomicInteger(0);
    final Runnable task = new Runnable() {

        public void run() {
            equal(startingGate.getPhase(), 0);
            startingGate.arriveAndAwaitAdvance();
            equal(startingGate.getPhase(), 1);
            int phase = phaser.arrive();
            if (phase == 0)
                count0.getAndIncrement();
            else if (phase == 1)
                count1.getAndIncrement();
            else
                fail();
        }
    };
    for (int i = 0; i < n; i++) threads.add(new Thread(task));
    for (Thread thread : threads) thread.start();
    for (Thread thread : threads) thread.join();
    equal(count0.get(), n);
    equal(count1.get(), 0);
    equal(phaser.getPhase(), 1);
}

//-------------------------------------------------------------
// Implementation - IdGenerator
//-------------------------------------------------------------
@Override
public String generateId() {
    StringBuilder sb = new StringBuilder();
    int bitsLeft = bitsPerId;
    while (bitsLeft > 0) {
        long random = ThreadLocalRandom.current().nextLong();
        if (bitsLeft < BITS_PER_LONG) {
            random >>>= (BITS_PER_LONG - bitsLeft);
        }
        encode(random, sb);
        bitsLeft -= BITS_PER_LONG;
    }
    while (sb.length() < encodedIdLength) {
        sb.append(characters[0]);
    }
    // It's possible we could generate a string larger than we expect.  Cut it down if needed.
    return sb.length() == encodedIdLength ? sb.toString() : sb.substring(0, encodedIdLength);
}

public static String random(int count, int start, int end, boolean letters, boolean numbers, char[] chars) {
    if (count == 0) {
        return "";
    } else if (count < 0) {
        throw new IllegalArgumentException("Requested random string length " + count + " is less than 0.");
    }
    if (chars != null && chars.length == 0) {
        throw new IllegalArgumentException("The chars array must not be empty");
    }
    if (start == 0 && end == 0) {
        if (chars != null) {
            end = chars.length;
        } else {
            if (!letters && !numbers) {
                end = Integer.MAX_VALUE;
            } else {
                end = 'z' + 1;
                start = ' ';
            }
        }
    } else {
        if (end <= start) {
            throw new IllegalArgumentException("Parameter end (" + end + ") must be greater than start (" + start + ")");
        }
    }
    final char[] buffer = new char[count];
    final int gap = end - start;
    ThreadLocalRandom random = ThreadLocalRandom.current();
    while (count-- != 0) {
        char ch;
        if (chars == null) {
            ch = (char) (random.nextInt(gap) + start);
        } else {
            ch = chars[random.nextInt(gap) + start];
        }
        if (letters && Character.isLetter(ch) || numbers && Character.isDigit(ch) || !letters && !numbers) {
            if (ch >= 56320 && ch <= 57343) {
                if (count == 0) {
                    count++;
                } else {
                    // low surrogate, insert high surrogate after putting it in
                    buffer[count] = ch;
                    count--;
                    buffer[count] = (char) (55296 + random.nextInt(128));
                }
            } else if (ch >= 55296 && ch <= 56191) {
                if (count == 0) {
                    count++;
                } else {
                    // high surrogate, insert low surrogate before putting it in
                    buffer[count] = (char) (56320 + random.nextInt(128));
                    count--;
                    buffer[count] = ch;
                }
            } else if (ch >= 56192 && ch <= 56319) {
                // private high surrogate, no effing clue, so skip it
                count++;
            } else {
                buffer[count] = ch;
            }
        } else {
            count++;
        }
    }
    return new String(buffer);
}

@Override
public boolean filter(ClientExchange exchange, FilterType type) throws Exception {
    assert type == FilterType.RESPONSE;
    Response response = exchange.getResponse();
    if (!status.equals(response.status))
        return true;
    Request request = exchange.getRequest();
    if (// we already tried to authenticate && failed
    request.getCredentials(proxy) != null)
        return true;
    Challenge challenge = response.getChallenge(proxy);
    if (challenge instanceof BasicChallenge) {
        request.setCredentials(basicCredentials, proxy);
        exchange.retry();
        return true;
    }
    if (challenge instanceof DigestChallenge) {
        DigestChallenge digestChallenge = (DigestChallenge) challenge;
        DigestCredentials digestCredentials = new DigestCredentials();
        digestCredentials.username = basicCredentials.user;
        digestCredentials.realm = digestChallenge.realm;
        digestCredentials.nonce = digestChallenge.nonce;
        digestCredentials.uri = request.uri;
        digestCredentials.algorithm = digestChallenge.algorithm;
        digestCredentials.opaque = digestChallenge.opaque;
        if (digestChallenge.qops != null && !digestChallenge.qops.isEmpty())
            digestCredentials.qop = digestChallenge.qops.contains("auth") ? "auth" : digestChallenge.qops.get(0);
        if ("MD5-sess".equals(digestCredentials.algorithm) || digestCredentials.qop != null) {
            byte[] bytes = new byte[4];
            ThreadLocalRandom.current().nextBytes(bytes);
            digestCredentials.cnonce = printHexBinary(bytes).toLowerCase();
        }
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        String a1 = basicCredentials.user + ':' + digestChallenge.realm + ':' + basicCredentials.password;
        String ha1 = printHexBinary(md5.digest(a1.getBytes(UTF_8))).toLowerCase();
        md5.reset();
        if ("MD5-sess".equals(digestCredentials.algorithm)) {
            ha1 = printHexBinary(md5.digest((ha1 + ':' + digestCredentials.nonce + ':' + digestCredentials.cnonce).getBytes(UTF_8))).toLowerCase();
            md5.reset();
        }
        md5.update((request.method + ":" + request.uri).getBytes(UTF_8));
        if ("auth-init".equals(digestCredentials.qop)) {
            // ha2 = md5(method:uri:md5(payload)
            if (request.getPayload().getContentLength() == 0)
                md5.update((byte) ':');
            else {
                // not implemented
                return true;
            }
        }
        String ha2 = printHexBinary(md5.digest()).toLowerCase();
        md5.reset();
        String respString = ha1 + ':' + digestChallenge.nonce;
        if (digestCredentials.qop != null) {
            digestCredentials.nc = String.format("%08x", 1);
            respString += ':' + digestCredentials.nc + ':' + digestCredentials.cnonce + ':' + digestCredentials.qop;
        }
        respString += ':' + ha2;
        digestCredentials.response = printHexBinary(md5.digest(respString.getBytes(UTF_8))).toLowerCase();
        request.setCredentials(digestCredentials, proxy);
        exchange.retry();
        return true;
    }
    // we dont understand the challenge
    return true;
}