From d2b358b21d81085654f4bf49c2aa70eeea83bb17 Mon Sep 17 00:00:00 2001
From: yanyir <87400809+yanyir@users.noreply.github.com>
Date: Wed, 25 Oct 2023 15:04:04 +0800
Subject: [PATCH] use jdk ThreadLocalRandom (#2686)
---
.../taobao/arthas/core/util/StringUtils.java | 1 +
.../arthas/core/util/ThreadLocalRandom.java | 271 ------------------
.../arthas/core/util/metrics/RateCounter.java | 3 +-
3 files changed, 2 insertions(+), 273 deletions(-)
delete mode 100644 core/src/main/java/com/taobao/arthas/core/util/ThreadLocalRandom.java
diff --git a/core/src/main/java/com/taobao/arthas/core/util/StringUtils.java b/core/src/main/java/com/taobao/arthas/core/util/StringUtils.java
index d243687b3b..58993479b5 100644
--- a/core/src/main/java/com/taobao/arthas/core/util/StringUtils.java
+++ b/core/src/main/java/com/taobao/arthas/core/util/StringUtils.java
@@ -30,6 +30,7 @@
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
+import java.util.concurrent.ThreadLocalRandom;
import com.alibaba.arthas.deps.org.slf4j.Logger;
import com.alibaba.arthas.deps.org.slf4j.LoggerFactory;
diff --git a/core/src/main/java/com/taobao/arthas/core/util/ThreadLocalRandom.java b/core/src/main/java/com/taobao/arthas/core/util/ThreadLocalRandom.java
deleted file mode 100644
index 3d2a7c4df5..0000000000
--- a/core/src/main/java/com/taobao/arthas/core/util/ThreadLocalRandom.java
+++ /dev/null
@@ -1,271 +0,0 @@
-package com.taobao.arthas.core.util;
-import java.security.SecureRandom;
-import java.util.Random;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicLong;
-
-/**
- * A random number generator isolated to the current thread. Like the global {@link java.util.Random} generator used by
- * the {@link java.lang.Math} class, a {@code ThreadLocalRandom} is initialized with an internally generated seed that
- * may not otherwise be modified. When applicable, use of {@code ThreadLocalRandom} rather than shared {@code Random}
- * objects in concurrent programs will typically encounter much less overhead and contention. Use of
- * {@code ThreadLocalRandom} is particularly appropriate when multiple tasks (for example, each a
- * {@link io.netty.util.internal.chmv8.ForkJoinTask}) use random numbers in parallel in thread pools.
- *
- *
- * Usages of this class should typically be of the form: {@code ThreadLocalRandom.current().nextX(...)} (where {@code X}
- * is {@code Int}, {@code Long}, etc). When all usages are of this form, it is never possible to accidently share a
- * {@code ThreadLocalRandom} across multiple threads.
- *
- *
- * This class also provides additional commonly used bounded random generation methods.
- *
- * //since 1.7 //author Doug Lea
- */
-@SuppressWarnings("all")
-public class ThreadLocalRandom extends Random {
- private static final AtomicLong seedUniquifier = new AtomicLong();
-
- private static volatile long initialSeedUniquifier;
-
- public static void setInitialSeedUniquifier(long initialSeedUniquifier) {
- ThreadLocalRandom.initialSeedUniquifier = initialSeedUniquifier;
- }
-
- public static synchronized long getInitialSeedUniquifier() {
- // Use the value set via the setter.
- long initialSeedUniquifier = ThreadLocalRandom.initialSeedUniquifier;
- // Otherwise, generate one.
- if (initialSeedUniquifier == 0) {
- // Try to generate a real random number from /dev/random.
- // Get from a different thread to avoid blocking indefinitely on a machine without much entrophy.
- final BlockingQueue queue = new LinkedBlockingQueue();
- Thread generatorThread = new Thread("initialSeedUniquifierGenerator") {
- @Override
- public void run() {
- SecureRandom random = new SecureRandom(); // Get the real random seed from /dev/random
- queue.add(random.nextLong());
- }
- };
- generatorThread.start();
-
- // Get the random seed from the thread with timeout.
- final long timeoutSeconds = 3;
- final long deadLine = System.nanoTime() + TimeUnit.SECONDS.toNanos(timeoutSeconds);
- for (;;) {
- long waitTime = deadLine - System.nanoTime();
- if (waitTime <= 0) {
- break;
- }
-
- try {
- Long result = queue.poll(waitTime, TimeUnit.NANOSECONDS);
- if (result != null) {
- initialSeedUniquifier = result;
- break;
- }
- } catch (InterruptedException ignore) {
- // Ignore
- }
- }
-
- // Just in case the initialSeedUniquifier is zero or some other constant
- initialSeedUniquifier ^= 0x3255ecdc33bae119L; // just a meaningless random number
- initialSeedUniquifier ^= Long.reverse(System.nanoTime());
-
- ThreadLocalRandom.initialSeedUniquifier = initialSeedUniquifier;
- }
-
- return initialSeedUniquifier;
- }
-
- private static long newSeed() {
- for (;;) {
- final long current = seedUniquifier.get();
- final long actualCurrent = current != 0 ? current : getInitialSeedUniquifier();
-
- // L'Ecuyer, "Tables of Linear Congruential Generators of Different Sizes and Good Lattice Structure", 1999
- final long next = actualCurrent * 181783497276652981L;
-
- if (seedUniquifier.compareAndSet(current, next)) {
- return next ^ System.nanoTime();
- }
- }
- }
-
- // same constants as Random, but must be redeclared because private
- private static final long multiplier = 0x5DEECE66DL;
- private static final long addend = 0xBL;
- private static final long mask = (1L << 48) - 1;
-
- /**
- * The random seed. We can't use super.seed.
- */
- private long rnd;
-
- /**
- * Initialization flag to permit calls to setSeed to succeed only while executing the Random constructor. We can't
- * allow others since it would cause setting seed in one part of a program to unintentionally impact other usages by
- * the thread.
- */
- boolean initialized;
-
- // Padding to help avoid memory contention among seed updates in
- // different TLRs in the common case that they are located near
- // each other.
- private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
-
- /**
- * Constructor called only by localRandom.initialValue.
- */
- ThreadLocalRandom() {
- super(newSeed());
- initialized = true;
- }
-
- /**
- * The actual ThreadLocal
- */
- private static final ThreadLocal localRandom = new ThreadLocal() {
- protected ThreadLocalRandom initialValue() {
- return new ThreadLocalRandom();
- }
- };
-
- /**
- * Returns the current thread's {@code ThreadLocalRandom}.
- *
- * @return the current thread's {@code ThreadLocalRandom}
- */
- public static ThreadLocalRandom current() {
- return localRandom.get();
- }
-
- /**
- * Throws {@code UnsupportedOperationException}. Setting seeds in this generator is not supported.
- *
- * @throws UnsupportedOperationException
- * always
- */
- public void setSeed(long seed) {
- if (initialized) {
- throw new UnsupportedOperationException();
- }
- rnd = (seed ^ multiplier) & mask;
- }
-
- protected int next(int bits) {
- rnd = (rnd * multiplier + addend) & mask;
- return (int) (rnd >>> (48 - bits));
- }
-
- /**
- * Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound
- * (exclusive).
- *
- * @param least
- * the least value returned
- * @param bound
- * the upper bound (exclusive)
- * @throws IllegalArgumentException
- * if least greater than or equal to bound
- * @return the next value
- */
- public int nextInt(int least, int bound) {
- if (least >= bound) {
- throw new IllegalArgumentException();
- }
- return nextInt(bound - least) + least;
- }
-
- /**
- * Returns a pseudorandom, uniformly distributed value between 0 (inclusive) and the specified value (exclusive).
- *
- * @param n
- * the bound on the random number to be returned. Must be positive.
- * @return the next value
- * @throws IllegalArgumentException
- * if n is not positive
- */
- public long nextLong(long n) {
- if (n <= 0) {
- throw new IllegalArgumentException("n must be positive");
- }
-
- // Divide n by two until small enough for nextInt. On each
- // iteration (at most 31 of them but usually much less),
- // randomly choose both whether to include high bit in result
- // (offset) and whether to continue with the lower vs upper
- // half (which makes a difference only if odd).
- long offset = 0;
- while (n >= Integer.MAX_VALUE) {
- int bits = next(2);
- long half = n >>> 1;
- long nextn = ((bits & 2) == 0) ? half : n - half;
- if ((bits & 1) == 0) {
- offset += n - nextn;
- }
- n = nextn;
- }
- return offset + nextInt((int) n);
- }
-
- /**
- * Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound
- * (exclusive).
- *
- * @param least
- * the least value returned
- * @param bound
- * the upper bound (exclusive)
- * @return the next value
- * @throws IllegalArgumentException
- * if least greater than or equal to bound
- */
- public long nextLong(long least, long bound) {
- if (least >= bound) {
- throw new IllegalArgumentException();
- }
- return nextLong(bound - least) + least;
- }
-
- /**
- * Returns a pseudorandom, uniformly distributed {@code double} value between 0 (inclusive) and the specified value
- * (exclusive).
- *
- * @param n
- * the bound on the random number to be returned. Must be positive.
- * @return the next value
- * @throws IllegalArgumentException
- * if n is not positive
- */
- public double nextDouble(double n) {
- if (n <= 0) {
- throw new IllegalArgumentException("n must be positive");
- }
- return nextDouble() * n;
- }
-
- /**
- * Returns a pseudorandom, uniformly distributed value between the given least value (inclusive) and bound
- * (exclusive).
- *
- * @param least
- * the least value returned
- * @param bound
- * the upper bound (exclusive)
- * @return the next value
- * @throws IllegalArgumentException
- * if least greater than or equal to bound
- */
- public double nextDouble(double least, double bound) {
- if (least >= bound) {
- throw new IllegalArgumentException();
- }
- return nextDouble() * (bound - least) + least;
- }
-
- private static final long serialVersionUID = -5851777807851030925L;
-}
\ No newline at end of file
diff --git a/core/src/main/java/com/taobao/arthas/core/util/metrics/RateCounter.java b/core/src/main/java/com/taobao/arthas/core/util/metrics/RateCounter.java
index 38d4211536..659fdc9aa2 100644
--- a/core/src/main/java/com/taobao/arthas/core/util/metrics/RateCounter.java
+++ b/core/src/main/java/com/taobao/arthas/core/util/metrics/RateCounter.java
@@ -2,8 +2,7 @@
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicLongArray;
-
-import com.taobao.arthas.core.util.ThreadLocalRandom;
+import java.util.concurrent.ThreadLocalRandom;
/**
*