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