safe-thread-local-random

An implementation of Random that delegates all methods to ThreadLocalRandom.current().

Usage

Simple example:

Random random = SafeThreadLocalRandom.get();
int random = random.nextInt();

Given the following IdGenerator.java:

/** Simple ID generator (not cryptographically secure). */
@ThreadSafe
public final class IdGenerator {
  private final Random random;
  public IdGenerator(Random random) {
    this.random = random;
  }

  public long getId() {
    return random.nextLong();
  }
}

We would never want to pass the result of ThreadLocalRandom.current() directly, because we would associate the random instance from our current thread with a utility that is shared between other threads, resulting in degraded performance. Passing the result of SafeThreadLocalRandom.get() produces an improvement because there is no contention between threads[1], all invocations are passed through to the calling thread's ThreadLocalRandom.

1. From https://docs.oracle.com/javase/8/docs/api/java/util/Random.html:

   Instances of java.util.Random are threadsafe. However, the concurrent use of the same java.util.Random instance across threads may encounter contention and consequent poor performance. Consider instead using ThreadLocalRandom in multithreaded designs.

Gradle Tasks

./gradlew tasks - to get the list of gradle tasks

Start Developing

Run one of the following commands:

• ./gradlew idea for IntelliJ
• ./gradlew eclipse for Eclipse