Interface RandomGenerator.LeapableGenerator

All Superinterfaces:: RandomGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.StreamableGenerator

All Known Subinterfaces:: RandomGenerator.ArbitrarilyJumpableGenerator

Enclosing interface:: RandomGenerator

public static interface RandomGenerator.LeapableGenerator extends RandomGenerator.JumpableGenerator

This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily not only jump but also leap forward, by a large amount (ex. 2¹²⁸), to a very distant point in the state cycle. Typically one will construct a series of 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.

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:: 17

Nested Class Summary

Nested classes/interfaces declared in interface RandomGenerator

RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.SplittableGenerator, RandomGenerator.StreamableGenerator

Modifier and Type	Interface	Description
`static interface`	`RandomGenerator.ArbitrarilyJumpableGenerator`	This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily jump forward, by an arbitrary amount, to a distant point in the state cycle.
`static interface`	`RandomGenerator.JumpableGenerator`	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.
`static interface`	`RandomGenerator.LeapableGenerator`	This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily not only jump but also leap forward, by a large amount (ex. 2¹²⁸), to a very distant point in the state cycle.
`static interface`	`RandomGenerator.SplittableGenerator`	This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can be split into two objects (the original one and a new one) each of which obey that same protocol (and therefore can be recursively split indefinitely).
`static interface`	`RandomGenerator.StreamableGenerator`	The `RandomGenerator.StreamableGenerator` interface augments the `RandomGenerator` interface to provide methods that return streams of `RandomGenerator` objects.

Method Summary

Modifier and Type	Method	Description
`RandomGenerator.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).
`default RandomGenerator.JumpableGenerator`	`copyAndLeap()`	Copy this generator, leap this generator forward, then return the copy.
`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.
`double`	`leapDistance()`	Returns the distance by which the `leap`() method will leap forward within the state cycle of this generator object.
`default Stream<RandomGenerator.JumpableGenerator>`	`leaps()`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator.JumpableGenerator` interface.
`default Stream<RandomGenerator.JumpableGenerator>`	`leaps(long streamSize)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator.JumpableGenerator` interface.
`static RandomGenerator.LeapableGenerator`	`of(String name)`	Returns an instance of `RandomGenerator.LeapableGenerator` that utilizes the `name` algorithm.

Methods declared in interface RandomGenerator

doubles, doubles, doubles, doubles, equiDoubles, ints, ints, ints, ints, isDeprecated, longs, longs, longs, longs, nextBoolean, nextBytes, nextDouble, nextDouble, nextDouble, nextExponential, nextFloat, nextFloat, nextFloat, nextGaussian, nextGaussian, nextInt, nextInt, nextInt, nextLong, nextLong, nextLong

Modifier and Type	Method	Description
`default DoubleStream`	`doubles()`	Returns an effectively unlimited stream of pseudorandomly chosen `double` values.
`default DoubleStream`	`doubles(double randomNumberOrigin, double randomNumberBound)`	Returns an effectively unlimited stream of pseudorandomly chosen `double` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default DoubleStream`	`doubles(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `double` values.
`default DoubleStream`	`doubles(long streamSize, double randomNumberOrigin, double randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `double` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default DoubleStream`	`equiDoubles(double left, double right, boolean isLeftIncluded, boolean isRightIncluded)`	Returns an effectively unlimited stream of pseudorandomly chosen `double` values, where each value is between the specified `left` boundary and the specified `right` boundary.
`default IntStream`	`ints()`	Returns an effectively unlimited stream of pseudorandomly chosen `int` values.
`default IntStream`	`ints(int randomNumberOrigin, int randomNumberBound)`	Returns an effectively unlimited stream of pseudorandomly chosen `int` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default IntStream`	`ints(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `int` values.
`default IntStream`	`ints(long streamSize, int randomNumberOrigin, int randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `int` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default boolean`	`isDeprecated()`	Return true if the implementation of RandomGenerator (algorithm) has been marked for deprecation.
`default LongStream`	`longs()`	Returns an effectively unlimited stream of pseudorandomly chosen `long` values.
`default LongStream`	`longs(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `long` values.
`default LongStream`	`longs(long randomNumberOrigin, long randomNumberBound)`	Returns an effectively unlimited stream of pseudorandomly chosen `long` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default LongStream`	`longs(long streamSize, long randomNumberOrigin, long randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `long` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default boolean`	`nextBoolean()`	Returns a pseudorandomly chosen `boolean` value.
`default void`	`nextBytes(byte[] bytes)`	Fills a user-supplied byte array with generated byte values pseudorandomly chosen uniformly from the range of values between -128 (inclusive) and 127 (inclusive).
`default double`	`nextDouble()`	Returns a pseudorandom `double` value between zero (inclusive) and one (exclusive).
`default double`	`nextDouble(double bound)`	Returns a pseudorandomly chosen `double` value between zero (inclusive) and the specified bound (exclusive).
`default double`	`nextDouble(double origin, double bound)`	Returns a pseudorandomly chosen `double` value between the specified origin (inclusive) and the specified bound (exclusive).
`default double`	`nextExponential()`	Returns a nonnegative `double` value pseudorandomly chosen from an exponential distribution whose mean is 1.
`default float`	`nextFloat()`	Returns a pseudorandom `float` value between zero (inclusive) and one (exclusive).
`default float`	`nextFloat(float bound)`	Returns a pseudorandomly chosen `float` value between zero (inclusive) and the specified bound (exclusive).
`default float`	`nextFloat(float origin, float bound)`	Returns a pseudorandomly chosen `float` value between the specified origin (inclusive) and the specified bound (exclusive).
`default double`	`nextGaussian()`	Returns a `double` value pseudorandomly chosen from a Gaussian (normal) distribution whose mean is 0 and whose standard deviation is 1.
`default double`	`nextGaussian(double mean, double stddev)`	Returns a `double` value pseudorandomly chosen from a Gaussian (normal) distribution with a mean and standard deviation specified by the arguments.
`default int`	`nextInt()`	Returns a pseudorandomly chosen `int` value.
`default int`	`nextInt(int bound)`	Returns a pseudorandomly chosen `int` value between zero (inclusive) and the specified bound (exclusive).
`default int`	`nextInt(int origin, int bound)`	Returns a pseudorandomly chosen `int` value between the specified origin (inclusive) and the specified bound (exclusive).
`long`	`nextLong()`	Returns a pseudorandomly chosen `long` value.
`default long`	`nextLong(long bound)`	Returns a pseudorandomly chosen `long` value between zero (inclusive) and the specified bound (exclusive).
`default long`	`nextLong(long origin, long bound)`	Returns a pseudorandomly chosen `long` value between the specified origin (inclusive) and the specified bound (exclusive).

Methods declared in interface RandomGenerator.JumpableGenerator

copyAndJump, jump, jumpDistance, jumps, jumps, rngs, rngs

Modifier and Type	Method	Description
`default RandomGenerator`	`copyAndJump()`	Copy this generator, jump this generator forward, then return the copy.
`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.
`double`	`jumpDistance()`	Returns the distance by which the `jump`() method will jump forward within the state cycle of this generator object.
`default Stream<RandomGenerator>`	`jumps()`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.
`default Stream<RandomGenerator>`	`jumps(long streamSize)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.
`default Stream<RandomGenerator>`	`rngs()`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.
`default Stream<RandomGenerator>`	`rngs(long streamSize)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.

Method Details

of

static RandomGenerator.LeapableGenerator of(String name)

Returns an instance of RandomGenerator.LeapableGenerator that utilizes the name algorithm.

Parameters:: name - Name of random number generator algorithm
Returns:: An instance of RandomGenerator.LeapableGenerator
Throws:: NullPointerException - if name is null; IllegalArgumentException - if the named algorithm is not found

copy

RandomGenerator.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 interface RandomGenerator.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.

leapDistance

double leapDistance()

Returns the distance by which the leap() method will leap forward within the state cycle of this generator object.

Returns:: the default leap distance (as a double value)

leaps

default Stream<RandomGenerator.JumpableGenerator> leaps()

Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the RandomGenerator.JumpableGenerator interface.

Implementation Requirements:: The default implementation produces a sequential stream that repeatedly calls copy() and leap() on this generator, and the copies become the generators produced by the stream.
Implementation Note:: It is permitted to implement this method in a manner equivalent to leaps (Long.MAX_VALUE).
Returns:: a stream of objects that implement the RandomGenerator.JumpableGenerator interface

leaps

default Stream<RandomGenerator.JumpableGenerator> leaps(long streamSize)

Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the RandomGenerator.JumpableGenerator interface.

Implementation Requirements:: The default implementation produces a sequential stream that repeatedly calls copy() and leap() 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 - if streamSize is less than zero

copyAndLeap

default RandomGenerator.JumpableGenerator copyAndLeap()

Copy this generator, leap this generator forward, then return the copy.

Implementation Requirements:: The default implementation copies this, leaps and then returns the copy.
Returns:: a copy of this generator object before the leap occurred

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