Interface RandomGenerator.JumpableGenerator

All Superinterfaces:: RandomGenerator, RandomGenerator.StreamableGenerator

All Known Subinterfaces:: RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.LeapableGenerator

Enclosing interface:: RandomGenerator

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.

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.JumpableGenerator`	`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`	`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.
`static RandomGenerator.JumpableGenerator`	`of(String name)`	Returns an instance of `RandomGenerator.JumpableGenerator` that utilizes the `name` algorithm.
`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.

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).

Method Details

of

static RandomGenerator.JumpableGenerator of(String name)

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

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

copy

RandomGenerator.JumpableGenerator 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).

Returns:: a new object that is a copy of this generator

jump

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.

jumpDistance

double jumpDistance()

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

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

jumps

default Stream<RandomGenerator> jumps()

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

Implementation Requirements:: The default implementation produces a sequential stream that repeatedly calls copy() and jump() 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 jumps (Long.MAX_VALUE).
Returns:: a stream of objects that implement the RandomGenerator interface

jumps

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.

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

rngs

default Stream<RandomGenerator> rngs()

Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the RandomGenerator interface. Ideally the generators in the stream will appear to be statistically independent.

Specified by:: rngs in interface RandomGenerator.StreamableGenerator
Implementation Requirements:: The default implementation calls jumps().
Returns:: a stream of objects that implement the RandomGenerator interface

rngs

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. Ideally the generators in the stream will appear to be statistically independent.

Specified by:: rngs in interface RandomGenerator.StreamableGenerator
Implementation Requirements:: The default implementation calls jumps(streamSize).
Parameters:: streamSize - the number of generators to generate
Returns:: a stream of objects that implement the RandomGenerator interface
Throws:: IllegalArgumentException - if streamSize is less than zero

copyAndJump

default RandomGenerator copyAndJump()

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

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

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