java.util.concurrent.ThreadLocalRandom#current ( )源码实例Demo

/**
 * Check concurrent operations.
 *
 * @param done Done flag.
 * @param node Node.
 */
private static void checkConcurrentOperations(AtomicBoolean done, Ignite node) {
    ThreadLocalRandom rnd = ThreadLocalRandom.current();

    boolean state = rnd.nextBoolean();

    while (!done.get()) {
        if (state)
            node.cluster().enableWal(CACHE_NAME);
        else
            node.cluster().disableWal(CACHE_NAME);

        state = !state;
    }

    try {
        Thread.sleep(rnd.nextLong(200, 1000));
    }
    catch (InterruptedException e) {
        throw new RuntimeException(e);
    }
}
 

public void update(@HttpQueryParameter("queries") String queries, Connection connection,
		ObjectResponse<World[]> response) throws SQLException {
	ThreadLocalRandom random = ThreadLocalRandom.current();
	int count = getQueryCount(queries);
	World[] worlds = new World[count];
	try (PreparedStatement statement = connection.prepareStatement("SELECT ID FROM WORLD WHERE ID = ?",
			ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY)) {
		for (int i = 0; i < worlds.length; i++) {
			statement.setInt(1, random.nextInt(1, 10001));
			ResultSet resultSet = statement.executeQuery();
			resultSet.next();
			worlds[i] = new World(resultSet.getInt(1), random.nextInt(1, 10001));
		}
	}
	Arrays.sort(worlds, (a, b) -> a.getId() - b.getId());
	try (PreparedStatement statement = connection
			.prepareStatement("UPDATE WORLD SET RANDOMNUMBER = ? WHERE ID = ?")) {
		for (int u = 0; u < worlds.length; u++) {
			statement.setInt(1, worlds[u].getRandomNumber());
			statement.setInt(2, worlds[u].getId());
			statement.addBatch();
		}
		statement.executeBatch();
	}
	response.send(worlds);
}
 

/** */
protected void loadData(IgniteEx node, int start, int end) {
    try (IgniteDataStreamer<Object, Object> streamer = node.dataStreamer(POI_CACHE_NAME)) {
        Random rnd = ThreadLocalRandom.current();

        for (int i = start; i < end; i++) {
            BinaryObject bo = node.binary().builder(POI_CLASS_NAME)
                .setField(NAME_FIELD_NAME, "POI_" + i, String.class)
                .setField(LATITUDE_FIELD_NAME, rnd.nextDouble(), Double.class)
                .setField(LONGITUDE_FIELD_NAME, rnd.nextDouble(), Double.class)
                .build();

            streamer.addData(i, bo);
        }
    }
}
 

/**
 * Each of a parallel sized stream of bounded ints is within bounds
 */
public void testBoundedInts() {
    AtomicInteger fails = new AtomicInteger(0);
    ThreadLocalRandom r = ThreadLocalRandom.current();
    long size = 12345L;
    for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
        for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
            final int lo = least, hi = bound;
            r.ints(size, lo, hi).parallel().
                    forEach(x -> {
                        if (x < lo || x >= hi)
                            fails.getAndIncrement();
                    });
        }
    }
    assertEquals(fails.get(), 0);
}
 

private List<BrokerGroup> select(final List<BrokerGroup> groups) {
    if (groups == null || groups.size() == 0) {
        return Collections.EMPTY_LIST;
    }
    if (groups.size() <= DEFAULT_MIN_NUM) {
        return groups;
    }

    final ThreadLocalRandom random = ThreadLocalRandom.current();
    final Set<BrokerGroup> resultSet = new HashSet<>(DEFAULT_MIN_NUM);
    while (resultSet.size() <= DEFAULT_MIN_NUM) {
        final int randomIndex = random.nextInt(groups.size());
        resultSet.add(groups.get(randomIndex));
    }

    return new ArrayList<>(resultSet);
}
 

@Override
public JChannelGroup select(CopyOnWriteGroupList groups, Directory directory) {
    JChannelGroup[] elements = groups.getSnapshot();
    int length = elements.length;

    if (length == 0) {
        return null;
    }

    if (length == 1) {
        return elements[0];
    }

    WeightArray weightArray = (WeightArray) groups.getWeightArray(elements, directory.directoryString());
    if (weightArray == null || weightArray.length() != length) {
        weightArray = WeightSupport.computeWeights(groups, elements, directory);
    }

    ThreadLocalRandom random = ThreadLocalRandom.current();

    if (weightArray.isAllSameWeight()) {
        return elements[random.nextInt(length)];
    }

    int nextIndex = getNextServerIndex(weightArray, length, random);

    return elements[nextIndex];
}
 

private int randomColor() {
    ThreadLocalRandom random = ThreadLocalRandom.current();
    double rand = random.nextDouble(1, 100);

    if (rand <= 0.164) {
        return DyeColor.PINK.getDyedData();
    }

    if (rand <= 15) {
        return random.nextBoolean() ? DyeColor.BLACK.getDyedData() : random.nextBoolean() ? DyeColor.GRAY.getDyedData() : DyeColor.LIGHT_GRAY.getDyedData();
    }

    return DyeColor.WHITE.getDyedData();
}
 

/**
 * A sequential unsized stream of longs generates at least 100 values
 */
public void testUnsizedLongsCountSeq() {
    LongAdder counter = new LongAdder();
    ThreadLocalRandom r = ThreadLocalRandom.current();
    long size = 100;
    r.longs().limit(size).forEach(x -> {
        counter.increment();
    });
    assertEquals(counter.sum(), size);
}
 

/**
 * Returns true iff this BigInteger passes the specified number of
 * Miller-Rabin tests. This test is taken from the DSA spec (NIST FIPS
 * 186-2).
 *
 * The following assumptions are made:
 * This BigInteger is a positive, odd number greater than 2.
 * iterations<=50.
 */
private boolean passesMillerRabin(int iterations, Random rnd) {
    // Find a and m such that m is odd and this == 1 + 2**a * m
    BigInteger thisMinusOne = this.subtract(ONE);
    BigInteger m = thisMinusOne;
    int a = m.getLowestSetBit();
    m = m.shiftRight(a);

    // Do the tests
    if (rnd == null) {
        rnd = ThreadLocalRandom.current();
    }
    for (int i=0; i < iterations; i++) {
        // Generate a uniform random on (1, this)
        BigInteger b;
        do {
            b = new BigInteger(this.bitLength(), rnd);
        } while (b.compareTo(ONE) <= 0 || b.compareTo(this) >= 0);

        int j = 0;
        BigInteger z = b.modPow(m, this);
        while (!((j == 0 && z.equals(ONE)) || z.equals(thisMinusOne))) {
            if (j > 0 && z.equals(ONE) || ++j == a)
                return false;
            z = z.modPow(TWO, this);
        }
    }
    return true;
}
 

private static Object randomValue(Class<?> type) {
    var random = ThreadLocalRandom.current();
    if (type == UUID.class) {
        return UUID.randomUUID();
    }
    if (type == LocalDate.class) {
        return LocalDate.of(
                random.nextInt(2000, 2100),
                random.nextInt(Month.JANUARY.getValue(), Month.DECEMBER.getValue() + 1),
                random.nextInt(1, Month.FEBRUARY.minLength() + 1));
    }
    if (type == Money.class) {
        return Money.of(
                random.nextDouble(0, 1000),
                pickRandom(Monetary.getCurrencies()));
    }
    if (type == Instant.class) {
        return Instant.ofEpochMilli(random.nextLong());
    }
    if (type == ZonedDateTime.class) {
        var zoneIds = ZoneId.getAvailableZoneIds();
        zoneIds.remove("GMT0"); // XXX: cannot be parsed by java.time.format.DateTimeFormatterBuilder.appendZoneRegionId - fixed in Java 9 https://bugs.openjdk.java.net/browse/JDK-8138664
        var zoneId = ZoneId.of(pickRandom(zoneIds));
        return Instant.ofEpochMilli(random.nextLong()).atZone(zoneId);
    }
    if (type == String.class) {
        return RandomStringUtils.randomAlphanumeric(random.nextInt(10));
    }
    if (type == int.class) {
        return random.nextInt();
    }
    if (type == Class.class) {
        return pickRandom(Arrays.asList(Integer.class, Long.class, Float.class, Double.class));
    }
    throw new IllegalArgumentException("Unsupported type: " + type);
}
 

/**
 * A sequential unsized stream of doubles generates at least 100 values
 */
public void testUnsizedDoublesCountSeq() {
    LongAdder counter = new LongAdder();
    ThreadLocalRandom r = ThreadLocalRandom.current();
    long size = 100;
    r.doubles().limit(size).forEach(x -> {
        counter.increment();
    });
    assertEquals(counter.sum(), size);
}
 

/**
 * A parallel sized stream of doubles generates the given number of values
 */
public void testDoublesCount() {
    LongAdder counter = new LongAdder();
    ThreadLocalRandom r = ThreadLocalRandom.current();
    long size = 0;
    for (int reps = 0; reps < REPS; ++reps) {
        counter.reset();
        r.doubles(size).parallel().forEach(x -> {
            counter.increment();
        });
        assertEquals(counter.sum(), size);
        size += 524959;
    }
}
 

/**
 * This simple test compares the output of {@link BaseState#xxHash64(long, long, long)} with the
 * output of {@link net.openhft.hashing.LongHashFunction}, that itself is tested against the
 * reference implementation in C.  This increase confidence that the xxHash function implemented
 * in this package is in fact the same xxHash function implemented in C.
 *
 * @author Roman Leventov
 * @author Lee Rhodes
 */
@Test
public void testXxHash() {
  Random random = ThreadLocalRandom.current();
  for (int len = 0; len < 100; len++) {
    byte[] bytes = new byte[len];
    for (int i = 0; i < 10; i++) {
      long zahXxHash = LongHashFunction.xx().hashBytes(bytes);
      long memoryXxHash = Memory.wrap(bytes).xxHash64(0, len, 0);
      assertEquals(memoryXxHash, zahXxHash);
      random.nextBytes(bytes);
    }
  }
}
 

void fillBuffer(SourceBuilder.TimestampedSourceBuffer<Trade> buffer) {
    ThreadLocalRandom rnd = ThreadLocalRandom.current();

    for (int i = 0; i < tradesPerSec; i++) {
        String ticker = symbols.get(rnd.nextInt(symbols.size()));
        long tradeTime = System.currentTimeMillis();
        Trade trade = new Trade(tradeTime, ticker, QUANTITY, rnd.nextInt(5000));
        buffer.add(trade, tradeTime);
    }

    LockSupport.parkNanos(TimeUnit.SECONDS.toNanos(1)); // sleep for 1 second
}
 

/**
 * A parallel sized stream of doubles generates the given number of values
 */
public void testDoublesCount() {
    LongAdder counter = new LongAdder();
    ThreadLocalRandom r = ThreadLocalRandom.current();
    long size = 0;
    for (int reps = 0; reps < REPS; ++reps) {
        counter.reset();
        r.doubles(size).parallel().forEach(x -> {
            counter.increment();
        });
        assertEquals(counter.sum(), size);
        size += 524959;
    }
}
 

public JinjavaInterpreter(
  Jinjava application,
  Context context,
  JinjavaConfig renderConfig
) {
  this.context = context;
  this.config = renderConfig;
  this.application = application;

  switch (config.getRandomNumberGeneratorStrategy()) {
    case THREAD_LOCAL:
      random = ThreadLocalRandom.current();
      break;
    case CONSTANT_ZERO:
      random = new ConstantZeroRandomNumberGenerator();
      break;
    case DEFERRED:
      random = new DeferredRandomNumberGenerator();
      break;
    default:
      throw new IllegalStateException(
        "No random number generator with strategy " +
        config.getRandomNumberGeneratorStrategy()
      );
  }

  this.expressionResolver =
    new ExpressionResolver(this, application.getExpressionFactory());
}
 

@Override
protected RpcClientEntity loadBalance(RpcClientEntity rpcClientEntity , String interfaceName, List<NettyClient> candidates) {
    if (candidates == null || candidates.size() == 0) {
        return null;
    }
    ThreadLocalRandom threadLocalRandom = ThreadLocalRandom.current();
    int index = threadLocalRandom.nextInt( candidates.size() );
    NettyClient nettyClient=candidates.get( index );
    RpcClientEntity entity=new RpcClientEntity();
    BeanUtils.copyProperties( nettyClient,entity );
    entity.setIsSyn( rpcClientEntity.isSyn() );
    entity.setRpcClz( rpcClientEntity.getRpcClz() );
    return entity;
}
 

public WobbleStroke(float detail, float amplitude, float basicStrokeWidth) {
        this.detail = detail;
        this.amplitude = amplitude;
        this.basicStrokeWidth = basicStrokeWidth;

        //noinspection SharedThreadLocalRandom
        rand = ThreadLocalRandom.current();
//        seed = System.nanoTime();
    }
 

@Override()
public Array<T> shuffle(int count) {
    final Random random = ThreadLocalRandom.current();
    final int length = length();
    for (int i=0; i<count; ++i) {
        for (int j=0; j<length; ++j) {
            this.swap(j, random.nextInt(length));
        }
    }
    return this;
}
 

public TraceContext(@Nullable TraceContext parent) {
    Random prng = ThreadLocalRandom.current();
    this.spanId = String.format("%016x", prng.nextLong());
    this.traceId = parent == null || parent.getTraceId().trim().isEmpty()
            ? nextTraceIdHigh(prng) + this.spanId
            : parent.getTraceId();
    this.parentId = parent == null || parent.getSpanId().trim().isEmpty()
            ? null
            : parent.getSpanId();
}