Class ThreadLocalRandom

java.lang.Object
java.util.Random
org.jboss.netty.util.internal.ThreadLocalRandom
All Implemented Interfaces:
Serializable
public final class ThreadLocalRandom extends Random
A random number generator isolated to the current thread. Like the global Random generator used by the Math class, a ThreadLocalRandom is initialized with an internally generated seed that may not otherwise be modified. When applicable, use of ThreadLocalRandom rather than shared Random objects in concurrent programs will typically encounter much less overhead and contention. Use of ThreadLocalRandom is particularly appropriate when multiple tasks use random numbers in parallel in thread pools.

Usages of this class should typically be of the form: ThreadLocalRandom.current().nextX(...) (where X is Int, Long, etc). When all usages are of this form, it is never possible to accidently share a ThreadLocalRandom across multiple threads.

This class also provides additional commonly used bounded random generation methods.

Since:
1.7
See Also:

  • Field Details

    • multiplier

      private static final long multiplier
      See Also:

    • addend

      private static final long addend
      See Also:

    • mask

      private static final long mask
      See Also:

    • rnd

      private long rnd
      The random seed. We can't use super.seed.

    • initialized

      private boolean initialized
      Initialization flag to permit the first and only allowed call to setSeed (inside Random constructor) to succeed. 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.

    • pad0

      private long pad0

    • pad1

      private long pad1

    • pad2

      private long pad2

    • pad3

      private long pad3

    • pad4

      private long pad4

    • pad5

      private long pad5

    • pad6

      private long pad6

    • pad7

      private long pad7

    • localRandom

      private static final ThreadLocal<ThreadLocalRandom> localRandom
      The actual ThreadLocal

    • serialVersionUID

      private static final long serialVersionUID
      See Also:

  • Constructor Details

    • ThreadLocalRandom

      public ThreadLocalRandom()

  • Method Details

    • current

      public static ThreadLocalRandom current()
      Returns the current thread's ThreadLocalRandom.
      Returns:
      the current thread's ThreadLocalRandom

    • setSeed

      public void setSeed(long seed)
      Throws UnsupportedOperationException. Setting seeds in this generator is not supported.
      Overrides:
      setSeed in class Random
      Throws:
      UnsupportedOperationException - always

    • next

      protected int next(int bits)
      Overrides:
      next in class Random