ArbitrarilyJumpableGenerator
interface ArbitrarilyJumpableGenerator : RandomGenerator.LeapableGenerator
| java.util.random.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.
Ideally, all ArbitrarilyJumpableGenerator objects produced by iterative jumping from a single original 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 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 ArbitrarilyJumpableGenerator; with care, different jump distances can be used to traverse the entire state cycle in various ways.
Objects that implement 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.
Summary
| Public methods | |
|---|---|
| abstract RandomGenerator.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). |
| open RandomGenerator.ArbitrarilyJumpableGenerator! |
copyAndJump(distance: Double)Copy this generator, jump this generator forward, then return the copy. |
| abstract Unit |
Alter the state of this pseudorandom number generator so as to jump forward a specified distance within its state cycle. |
| open Unit |
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. |
| abstract Unit |
jumpPowerOfTwo(logDistance: Int)Alter the state of this pseudorandom number generator so as to jump forward a distance equal to 2 |
| open Stream<RandomGenerator.ArbitrarilyJumpableGenerator!>! |
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the |
| open Stream<RandomGenerator.ArbitrarilyJumpableGenerator!>! |
Returns a stream producing the given |
| open Unit |
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. |
| open static RandomGenerator.ArbitrarilyJumpableGenerator! |
Returns an instance of |
| Inherited functions | |
|---|---|
Public methods
copy
abstract fun copy(): RandomGenerator.ArbitrarilyJumpableGenerator!
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).
| Return | |
|---|---|
RandomGenerator.ArbitrarilyJumpableGenerator! |
a new object that is a copy of this generator |
copyAndJump
open fun copyAndJump(distance: Double): RandomGenerator.ArbitrarilyJumpableGenerator!
Copy this generator, jump this generator forward, then return the copy.
| Parameters | |
|---|---|
distance |
Double: a distance to jump forward within the state cycle |
| Return | |
|---|---|
RandomGenerator.ArbitrarilyJumpableGenerator! |
a copy of this generator object before the jump occurred |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if distance is not greater than or equal to 0.0, or is greater than the period of this generator |
jump
abstract fun jump(distance: Double): Unit
Alter the state of this pseudorandom number generator so as to jump forward a specified distance within its state cycle.
| Parameters | |
|---|---|
distance |
Double: the distance to jump forward within the state cycle |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if distance is not greater than or equal to 0.0, or is greater than the period of this generator |
jump
open fun jump(): Unit
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 method jumpDistance().
jumpPowerOfTwo
abstract fun jumpPowerOfTwo(logDistance: Int): Unit
Alter the state of this pseudorandom number generator so as to jump forward a distance equal to 2logDistance within its state cycle.
| Parameters | |
|---|---|
logDistance |
Int: the base-2 logarithm of the distance to jump forward within the state cycle |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if logDistance is 2logDistance is greater than the period of this generator |
jumps
open fun jumps(distance: Double): Stream<RandomGenerator.ArbitrarilyJumpableGenerator!>!
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the ArbitrarilyJumpableGenerator interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.
| Parameters | |
|---|---|
distance |
Double: a distance to jump forward within the state cycle |
| Return | |
|---|---|
Stream<RandomGenerator.ArbitrarilyJumpableGenerator!>! |
a stream of objects that implement the RandomGenerator interface |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if distance is not greater than or equal to 0.0, or is greater than the period of this generator |
jumps
open fun jumps(
streamSize: Long,
distance: Double
): Stream<RandomGenerator.ArbitrarilyJumpableGenerator!>!
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the ArbitrarilyJumpableGenerator interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.
| Parameters | |
|---|---|
streamSize |
Long: the number of generators to generate |
distance |
Double: a distance to jump forward within the state cycle |
| Return | |
|---|---|
Stream<RandomGenerator.ArbitrarilyJumpableGenerator!>! |
a stream of objects that implement the RandomGenerator interface |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if streamSize is less than zero or if distance is not greater than or equal to 0.0, or is greater than the period of this generator |
leap
open fun leap(): Unit
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 method leapDistance().
of
open static fun of(name: String!): RandomGenerator.ArbitrarilyJumpableGenerator!
Returns an instance of ArbitrarilyJumpableGenerator that utilizes the name algorithm.
| Parameters | |
|---|---|
name |
String!: Name of random number generator algorithm |
| Return | |
|---|---|
RandomGenerator.ArbitrarilyJumpableGenerator! |
An instance of ArbitrarilyJumpableGenerator |
| Exceptions | |
|---|---|
java.lang.NullPointerException |
if name is null |
java.lang.IllegalArgumentException |
if the named algorithm is not found |