RandomGenerator.LeapableGenerator
public
static
interface
RandomGenerator.LeapableGenerator
implements
RandomGenerator.JumpableGenerator
java.util.random.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.
Typically one will construct a series of LeapableGenerator
objects by iterative leaping from a single original
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 LeapableGenerator
objects produced by iterative
leaping and jumping from a single original 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 JumpableGenerator
interface but need not also
implement the LeapableGenerator
interface. A typical strategy for
a multithreaded application is to create a single
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 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.
Summary
Public methods | |
---|---|
abstract
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. |
abstract
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. |
abstract
double
|
leapDistance()
Returns the distance by which the
|
default
Stream<RandomGenerator.JumpableGenerator>
|
leaps()
Returns an effectively unlimited stream of new pseudorandom number
generators, each of which implements the |
default
Stream<RandomGenerator.JumpableGenerator>
|
leaps(long streamSize)
Returns a stream producing the given |
static
RandomGenerator.LeapableGenerator
|
of(String name)
Returns an instance of |
Inherited methods | |
---|---|
Public methods
copy
public abstract 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).
Returns | |
---|---|
RandomGenerator.LeapableGenerator |
a new object that is a copy of this generator |
copyAndLeap
public 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 | |
---|---|
RandomGenerator.JumpableGenerator |
a copy of this generator object before the leap occurred |
leap
public abstract 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
public abstract double leapDistance ()
Returns the distance by which the
leap
() method will leap forward within
the state cycle of this generator object.
Returns | |
---|---|
double |
the default leap distance (as a double value) |
leaps
public Stream<RandomGenerator.JumpableGenerator> leaps ()
Returns an effectively unlimited stream of new pseudorandom number
generators, each of which implements the JumpableGenerator
interface.
Implementation Note:
- It is permitted to implement this method in a manner equivalent to
leaps
(Long.MAX_VALUE
).
Implementation Requirements:
Returns | |
---|---|
Stream<RandomGenerator.JumpableGenerator> |
a stream of objects that implement the JumpableGenerator interface |
leaps
public Stream<RandomGenerator.JumpableGenerator> leaps (long streamSize)
Returns a stream producing the given streamSize
number of new
pseudorandom number generators, each of which implements the
JumpableGenerator
interface.
Implementation Requirements:
Parameters | |
---|---|
streamSize |
long : the number of generators to generate |
Returns | |
---|---|
Stream<RandomGenerator.JumpableGenerator> |
a stream of objects that implement the JumpableGenerator interface |
Throws | |
---|---|
IllegalArgumentException |
if streamSize is less than zero |
of
public static RandomGenerator.LeapableGenerator of (String name)
Returns an instance of LeapableGenerator
that utilizes the
name
algorithm.
Parameters | |
---|---|
name |
String : Name of random number generator
algorithm |
Returns | |
---|---|
RandomGenerator.LeapableGenerator |
An instance of LeapableGenerator |
Throws | |
---|---|
NullPointerException |
if name is null |
IllegalArgumentException |
if the named algorithm is not found |