JumpableGenerator
interface JumpableGenerator : RandomGenerator.StreamableGenerator
| java.util.random.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.
Ideally, all JumpableGenerator objects produced by iterative jumping from a single original 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 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 java.util.random.RandomGenerator.JumpableGenerator#jumps() method is Stream<RandomGenerator> rather than Stream<JumpableGenerator>, even though the actual generator objects in that stream likely do also implement the JumpableGenerator interface.
Objects that implement 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.
Summary
| Public methods | |
|---|---|
| abstract 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). |
| open RandomGenerator! |
Copy this generator, jump this generator forward, then return the copy. |
| abstract 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 Double |
Returns the distance by which the |
| open Stream<RandomGenerator!>! |
jumps()Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the |
| open Stream<RandomGenerator!>! |
Returns a stream producing the given |
| open static RandomGenerator.JumpableGenerator! |
Returns an instance of |
| open Stream<RandomGenerator!>! |
rngs()Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the |
| open Stream<RandomGenerator!>! |
Returns a stream producing the given |
Public methods
copy
abstract fun copy(): RandomGenerator.JumpableGenerator!
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.JumpableGenerator! |
a new object that is a copy of this generator |
copyAndJump
open fun copyAndJump(): RandomGenerator!
Copy this generator, jump this generator forward, then return the copy.
| Return | |
|---|---|
RandomGenerator! |
a copy of this generator object before the jump occurred |
jump
abstract 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.
jumpDistance
abstract fun jumpDistance(): Double
Returns the distance by which the jump() method will jump forward within the state cycle of this generator object.
| Return | |
|---|---|
Double |
the default jump distance (as a double value) |
jumps
open fun jumps(): Stream<RandomGenerator!>!
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the RandomGenerator interface.
| Return | |
|---|---|
Stream<RandomGenerator!>! |
a stream of objects that implement the RandomGenerator interface |
jumps
open fun jumps(streamSize: Long): Stream<RandomGenerator!>!
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the RandomGenerator interface.
| Parameters | |
|---|---|
streamSize |
Long: the number of generators to generate |
| Return | |
|---|---|
Stream<RandomGenerator!>! |
a stream of objects that implement the RandomGenerator interface |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if streamSize is less than zero |
of
open static fun of(name: String!): RandomGenerator.JumpableGenerator!
Returns an instance of JumpableGenerator that utilizes the name algorithm.
| Parameters | |
|---|---|
name |
String!: Name of random number generator algorithm |
| Return | |
|---|---|
RandomGenerator.JumpableGenerator! |
An instance of JumpableGenerator |
| Exceptions | |
|---|---|
java.lang.NullPointerException |
if name is null |
java.lang.IllegalArgumentException |
if the named algorithm is not found |
rngs
open fun rngs(): Stream<RandomGenerator!>!
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.
| Return | |
|---|---|
Stream<RandomGenerator!>! |
a stream of objects that implement the RandomGenerator interface |
rngs
open fun rngs(streamSize: Long): Stream<RandomGenerator!>!
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.
| Parameters | |
|---|---|
streamSize |
Long: the number of generators to generate |
| Return | |
|---|---|
Stream<RandomGenerator!>! |
a stream of objects that implement the RandomGenerator interface |
| Exceptions | |
|---|---|
java.lang.IllegalArgumentException |
if streamSize is less than zero |