- All Superinterfaces:
-
RandomGenerator
,RandomGenerator.StreamableGenerator
- All Known Subinterfaces:
-
RandomGenerator.ArbitrarilyJumpableGenerator
,RandomGenerator.LeapableGenerator
- All Known Implementing Classes:
-
RandomSupport.AbstractArbitrarilyJumpableGenerator
- Enclosing interface:
- RandomGenerator
public static interface RandomGenerator.JumpableGenerator extends RandomGenerator.StreamableGenerator
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 jump
() 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.
An implementation of the RandomGenerator.JumpableGenerator
interface must provide concrete definitions for the methods nextLong
(), period
(), copy
(), jump
(), and defaultJumpDistance
(). Default implementations are provided for all other methods.
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:
- 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.JumpableGenerator
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).default RandomGenerator
Copy this generator, jump this generator forward, then return the copy.double
Returns the distance by which thejump
() method will jump forward within the state cycle of this generator object.Returns aRandomGeneratorFactory
that can produce instances ofRandomGenerator.JumpableGenerator
that utilize thename
algorithm.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.default Stream<RandomGenerator>
jumps()
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator
interface.default Stream<RandomGenerator>
jumps(long streamSize)
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator
interface.Returns an instance ofRandomGenerator.JumpableGenerator
that utilizes thename
algorithm.default Stream<RandomGenerator>
rngs()
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator
interface.default Stream<RandomGenerator>
rngs(long streamSize)
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator
interface.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
-
Method Details
-
all
Returns a stream of all availableRandomGenerator.JumpableGenerator
factories.- Returns:
-
Stream of all available
RandomGenerator.JumpableGenerator
factories.
-
of
Returns an instance ofRandomGenerator.JumpableGenerator
that utilizes thename
algorithm.- Parameters:
-
name
- Name of random number generator algorithm - Returns:
-
An instance of
RandomGenerator.JumpableGenerator
-
factoryOf
Returns aRandomGeneratorFactory
that can produce instances ofRandomGenerator.JumpableGenerator
that utilize thename
algorithm.- Parameters:
-
name
- Name of random number generator algorithm - Returns:
-
RandomGeneratorFactory
ofRandomGenerator.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. -
defaultJumpDistance
double defaultJumpDistance()Returns the distance by which thejump
() method will jump forward within the state cycle of this generator object.- Returns:
-
the default jump distance (as a
double
value)
-
jumps
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator
interface.- Implementation Note:
-
It is permitted to implement this method in a manner equivalent to
jumps
(Long.MAX_VALUE
). The default implementation produces a sequential stream that repeatedly callscopy
() andjump
() on this generator, and the copies become the generators produced by the stream. - Returns:
-
a stream of objects that implement the
RandomGenerator
interface
-
jumps
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator
interface.- Implementation Note:
-
The default implementation produces a sequential stream that repeatedly calls
copy
() andjump
() 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
- ifstreamSize
is less than zero
-
rngs
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements theRandomGenerator
interface. Ideally the generators in the stream will appear to be statistically independent.- Specified by:
-
rngs
in interfaceRandomGenerator.StreamableGenerator
- Implementation Note:
-
The default implementation calls
jump
(). - Returns:
-
a stream of objects that implement the
RandomGenerator
interface
-
rngs
Returns a stream producing the givenstreamSize
number of new pseudorandom number generators, each of which implements theRandomGenerator
interface. Ideally the generators in the stream will appear to be statistically independent.- Specified by:
-
rngs
in interfaceRandomGenerator.StreamableGenerator
- Implementation Note:
-
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
- ifstreamSize
is less than zero
-
copyAndJump
Copy this generator, jump this generator forward, then return the copy.- Returns:
- a copy of this generator object before the jump occurred
-