- All Superinterfaces:
-
RandomGenerator
,RandomGenerator.JumpableGenerator
,RandomGenerator.StreamableGenerator
- All Known Subinterfaces:
-
RandomGenerator.ArbitrarilyJumpableGenerator
- All Known Implementing Classes:
-
RandomSupport.AbstractArbitrarilyJumpableGenerator
- Enclosing interface:
- RandomGenerator
public static interface RandomGenerator.LeapableGenerator extends RandomGenerator.JumpableGenerator
RandomGenerator.LeapableGenerator
objects by iterative leaping from a single original RandomGenerator.LeapableGenerator
object, and then for each such object produce a subseries of objects by iterative jumping. There is little conceptual difference between leaping and jumping, but typically a leap will be a very long jump in the state cycle (perhaps distance 2128 or so).
Ideally, all RandomGenerator.LeapableGenerator
objects produced by iterative leaping and jumping from a single original RandomGenerator.LeapableGenerator
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 leaps
method is used to produce (by jumping) a number of objects no larger than 264. Implementors are advised to use algorithms whose period is at least 2191.
Methods are provided to perform a single leap operation and also to produce a stream of generators produced from the original by iterative copying and leaping of internal state. The generators produced must implement the RandomGenerator.JumpableGenerator
interface but need not also implement the RandomGenerator.LeapableGenerator
interface. A typical strategy for a multithreaded application is to create a single RandomGenerator.LeapableGenerator
object, calls its leaps
method exactly once, and then parcel out generators from the resulting stream, one to each thread. Then the jump
() method of each such generator be called to produce a substream of generator objects.
An implementation of the RandomGenerator.LeapableGenerator
interface must provide concrete definitions for the methods nextLong
(), copy
(), jump
(), defaultJumpDistance
(), leap
(), and defaultLeapDistance
(). Default implementations are provided for all other methods.
Objects that implement RandomGenerator.LeapableGenerator
are typically not cryptographically secure. Consider instead using SecureRandom
to get a cryptographically secure pseudo-random number generator for use by security-sensitive applications.
- Since:
- 16
-
Nested Class Summary
Nested classes/interfaces declared in interface java.util.random.RandomGenerator
RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.RandomGeneratorProperty, RandomGenerator.SplittableGenerator, RandomGenerator.StreamableGenerator
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Field Summary
Fields declared in interface java.util.random.RandomGenerator
HUGE_PERIOD, TRULY_RANDOM, UNKNOWN_PERIOD
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Method Summary
Modifier and TypeMethodDescriptionall()
Returns a stream of all availableRandomGenerator.LeapableGenerator
factories.copy()
Returns a new generator whose internal state is an exact copy of this generator (therefore their future behavior should be identical if subjected to the same series of operations).Copy this generator, leap this generator forward, then return the copy.double
Returns the distance by which theleap
() method will leap forward within the state cycle of this generator object.Returns aRandomGeneratorFactory
that can produce instances ofRandomGenerator.LeapableGenerator
that utilize thename
algorithm.void
leap()
Alter the state of this pseudorandom number generator so as to leap forward a large, fixed distance (typically 296 or more) within its state cycle.default Stream<RandomGenerator.JumpableGenerator>
leaps()
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator.JumpableGenerator
interface.default Stream<RandomGenerator.JumpableGenerator>
leaps(long streamSize)
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator.JumpableGenerator
interface.Returns an instance ofRandomGenerator.LeapableGenerator
that utilizes thename
algorithm.Methods declared in interface java.util.random.RandomGenerator
doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, nextBoolean, nextBytes, nextDouble, nextDouble, nextDouble, nextExponential, nextFloat, nextFloat, nextFloat, nextGaussian, nextGaussian, nextInt, nextInt, nextInt, nextLong, nextLong, nextLong
Methods declared in interface java.util.random.RandomGenerator.JumpableGenerator
copyAndJump, defaultJumpDistance, jump, jumps, jumps, rngs, rngs
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Method Details
-
all
Returns a stream of all availableRandomGenerator.LeapableGenerator
factories.- Returns:
-
Stream of all available
RandomGenerator.LeapableGenerator
factories.
-
of
Returns an instance ofRandomGenerator.LeapableGenerator
that utilizes thename
algorithm.- Parameters:
-
name
- Name of random number generator algorithm - Returns:
-
An instance of
RandomGenerator.LeapableGenerator
-
factoryOf
Returns aRandomGeneratorFactory
that can produce instances ofRandomGenerator.LeapableGenerator
that utilize thename
algorithm.- Parameters:
-
name
- Name of random number generator algorithm - Returns:
-
RandomGeneratorFactory
ofRandomGenerator.LeapableGenerator
-
copy
Returns a new generator whose internal state is an exact copy of this generator (therefore their future behavior should be identical if subjected to the same series of operations).- Specified by:
-
copy
in interfaceRandomGenerator.JumpableGenerator
- Returns:
- a new object that is a copy of this generator
-
leap
void leap()Alter the state of this pseudorandom number generator so as to leap forward a large, fixed distance (typically 296 or more) within its state cycle. -
defaultLeapDistance
double defaultLeapDistance()Returns the distance by which theleap
() method will leap forward within the state cycle of this generator object.- Returns:
-
the default leap distance (as a
double
value)
-
leaps
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator.JumpableGenerator
interface.- Implementation Note:
-
It is permitted to implement this method in a manner equivalent to
leaps
(Long.MAX_VALUE
). The default implementation produces a sequential stream that repeatedly callscopy
() andleap
() on this generator, and the copies become the generators produced by the stream. - Returns:
-
a stream of objects that implement the
RandomGenerator.JumpableGenerator
interface
-
leaps
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator.JumpableGenerator
interface.- Implementation Note:
-
The default implementation produces a sequential stream that repeatedly calls
copy
() andleap
() on this generator, and the copies become the generators produced by the stream. - Parameters:
-
streamSize
- the number of generators to generate - Returns:
-
a stream of objects that implement the
RandomGenerator.JumpableGenerator
interface - Throws:
-
IllegalArgumentException
- ifstreamSize
is less than zero
-
copyAndLeap
Copy this generator, leap this generator forward, then return the copy.- Returns:
- a copy of this generator object before the leap occurred
-