Module java.base

Interface RandomGenerator.JumpableGenerator

All Superinterfaces:
RandomGenerator, RandomGenerator.StreamableGenerator
All Known Subinterfaces:
RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.LeapableGenerator
Enclosing interface:

public static interface RandomGenerator.JumpableGenerator extends RandomGenerator.StreamableGenerator
This interface is designed to provide a common protocol for objects that generate pseudorandom values and can easily jump forward, by a moderate amount (ex. 264) to a distant point in the state cycle.

Ideally, all RandomGenerator.JumpableGenerator objects produced by iterative jumping from a single original RandomGenerator.JumpableGenerator object are statistically independent of one another and individually uniform. In practice, one must settle for some approximation to independence and uniformity. In particular, a specific implementation may assume that each generator in a stream produced by the jump() method is used to produce a number of values no larger than either 264 or the square root of its period. Implementors are advised to use algorithms whose period is at least 2127.

Methods are provided to perform a single jump operation and also to produce a stream of generators produced from the original by iterative copying and jumping of internal state. A typical strategy for a multithreaded application is to create a single RandomGenerator.JumpableGenerator object, calls its jump() method exactly once, and then parcel out generators from the resulting stream, one to each thread. It is generally not a good idea to call jump() on a generator that was itself produced by the jump() method, because the result may be a generator identical to another generator already produce by that call to the jump() method. For this reason, the return type of the jumps() method is Stream<RandomGenerator> rather than Stream<RandomGenerator.JumpableGenerator>, even though the actual generator objects in that stream likely do also implement the RandomGenerator.JumpableGenerator interface.

Objects that implement RandomGenerator.JumpableGenerator are typically not cryptographically secure. Consider instead using SecureRandom to get a cryptographically secure pseudo-random number generator for use by security-sensitive applications.