- All Superinterfaces:
-
RandomGenerator
,RandomGenerator.JumpableGenerator
,RandomGenerator.LeapableGenerator
,RandomGenerator.StreamableGenerator
- All Known Implementing Classes:
-
RandomSupport.AbstractArbitrarilyJumpableGenerator
- Enclosing interface:
- RandomGenerator
public static interface RandomGenerator.ArbitrarilyJumpableGenerator extends RandomGenerator.LeapableGenerator
Ideally, all RandomGenerator.ArbitrarilyJumpableGenerator
objects produced by iterative jumping from a single original RandomGenerator.ArbitrarilyJumpableGenerator
object are statistically independent of one another and individually uniform, provided that they do not traverse overlapping portions of the state cycle. 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 the jump distance specified. Implementors are advised to use algorithms whose period is at least 2127.
For many applications, it suffices to jump forward by a power of two or some small multiple of a power of two, but this power of two may not be representable as a long
value. To avoid the use of BigInteger
values as jump distances, double
values are used instead.
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.ArbitrarilyJumpableGenerator
object, call its jump
() method exactly once, and then parcel out generators from the resulting stream, one to each thread. However, each generator produced also has type RandomGenerator.ArbitrarilyJumpableGenerator
; with care, different jump distances can be used to traverse the entire state cycle in various ways.
An implementation of the RandomGenerator.ArbitrarilyJumpableGenerator
interface must provide concrete definitions for the methods nextLong
(), copy
(), jump
(double), defaultJumpDistance
(), and defaultLeapDistance()
. Default implementations are provided for all other methods. Perhaps the most convenient way to implement this interface is to extend the abstract class RandomSupport.AbstractArbitrarilyJumpableGenerator
, which provides spliterator-based implementations of the methods ints
(), longs
(), doubles
(), rngs
(), jump
(), and leaps
().
Objects that implement RandomGenerator.ArbitrarilyJumpableGenerator
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
-
Field Summary
Fields declared in interface java.util.random.RandomGenerator
HUGE_PERIOD, TRULY_RANDOM, UNKNOWN_PERIOD
-
Method Summary
Modifier and TypeMethodDescriptionall()
Returns a stream of all availableRandomGenerator.ArbitrarilyJumpableGenerator
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).copyAndJump(double distance)
Copy this generator, jump this generator forward, then return the copy.Returns aRandomGeneratorFactory
that can produce instances ofRandomGenerator.ArbitrarilyJumpableGenerator
that utilize thename
algorithm.default void
jump()
Alter the state of this pseudorandom number generator so as to jump forward a large, fixed distance (typically 264 or more) within its state cycle.void
jump(double distance)
Alter the state of this pseudorandom number generator so as to jump forward a specified distance within its state cycle.void
jumpPowerOfTwo(int logDistance)
Alter the state of this pseudorandom number generator so as to jump forward a distance equal to 2logDistance
within its state cycle.jumps(double distance)
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator.ArbitrarilyJumpableGenerator
interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.jumps(long streamSize, double distance)
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator.ArbitrarilyJumpableGenerator
interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.default void
leap()
Alter the state of this pseudorandom number generator so as to jump forward a very large, fixed distance (typically 2128 or more) within its state cycle.Returns an instance ofRandomGenerator.ArbitrarilyJumpableGenerator
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, jumps, jumps, rngs, rngs
Methods declared in interface java.util.random.RandomGenerator.LeapableGenerator
copyAndLeap, defaultLeapDistance, leaps, leaps
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Method Details
-
all
Returns a stream of all availableRandomGenerator.ArbitrarilyJumpableGenerator
factories.- Returns:
-
Stream of all available
RandomGenerator.ArbitrarilyJumpableGenerator
factories.
-
of
Returns an instance ofRandomGenerator.ArbitrarilyJumpableGenerator
that utilizes thename
algorithm.- Parameters:
-
name
- Name of random number generator algorithm - Returns:
-
An instance of
RandomGenerator.ArbitrarilyJumpableGenerator
-
factoryOf
Returns aRandomGeneratorFactory
that can produce instances ofRandomGenerator.ArbitrarilyJumpableGenerator
that utilize thename
algorithm.- Parameters:
-
name
- Name of random number generator algorithm - Returns:
-
RandomGeneratorFactory
ofRandomGenerator.ArbitrarilyJumpableGenerator
-
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
- Specified by:
-
copy
in interfaceRandomGenerator.LeapableGenerator
- Returns:
- a new object that is a copy of this generator
-
jumpPowerOfTwo
void jumpPowerOfTwo(int logDistance)Alter the state of this pseudorandom number generator so as to jump forward a distance equal to 2logDistance
within its state cycle.- Parameters:
-
logDistance
- the base-2 logarithm of the distance to jump forward within the state cycle - Throws:
-
IllegalArgumentException
- iflogDistance
is NaN or negative, or if 2logDistance
is greater than the period of this generator
-
jump
void jump(double distance)Alter the state of this pseudorandom number generator so as to jump forward a specified distance within its state cycle.- Parameters:
-
distance
- the distance to jump forward within the state cycle - Throws:
-
IllegalArgumentException
- ifdistance
is Nan, negative, or greater than the period of this generator
-
jump
default void jump()Alter the state of this pseudorandom number generator so as to jump forward a large, fixed distance (typically 264 or more) within its state cycle. The distance used is that returned by methoddefaultJumpDistance
().- Specified by:
-
jump
in interfaceRandomGenerator.JumpableGenerator
-
jumps
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator.ArbitrarilyJumpableGenerator
interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.- Implementation Note:
-
This method is implemented to be equivalent to
jumps
(Long.MAX_VALUE
). - Parameters:
-
distance
- a distance to jump forward within the state cycle - Returns:
-
a stream of objects that implement the
RandomGenerator
interface
-
jumps
default Stream<RandomGenerator.ArbitrarilyJumpableGenerator> jumps(long streamSize, double distance)Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator.ArbitrarilyJumpableGenerator
interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.- Parameters:
-
streamSize
- the number of generators to generate -
distance
- a distance to jump forward within the state cycle - Returns:
-
a stream of objects that implement the
RandomGenerator
interface - Throws:
-
IllegalArgumentException
- ifstreamSize
is less than zero
-
leap
default void leap()Alter the state of this pseudorandom number generator so as to jump forward a very large, fixed distance (typically 2128 or more) within its state cycle. The distance used is that returned by methoddefaultLeapDistance
().- Specified by:
-
leap
in interfaceRandomGenerator.LeapableGenerator
-
copyAndJump
Copy this generator, jump this generator forward, then return the copy.- Parameters:
-
distance
- a distance to jump forward within the state cycle - Returns:
- a copy of this generator object before the jump occurred
-