Module java.base
Package java.util.random

Interface RandomGenerator

All Known Subinterfaces:
RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.SplittableGenerator, RandomGenerator.StreamableGenerator
All Known Implementing Classes:
Random, SecureRandom, SplittableRandom, ThreadLocalRandom
public interface RandomGenerator
The RandomGenerator interface is designed to provide a common protocol for objects that generate random or (more typically) pseudorandom sequences of numbers (or Boolean values). Such a sequence may be obtained by either repeatedly invoking a method that returns a single pseudorandomly chosen value, or by invoking a method that returns a stream of pseudorandomly chosen values.

Ideally, given an implicitly or explicitly specified range of values, each value would be chosen independently and uniformly from that range. In practice, one may have to settle for some approximation to independence and uniformity.

In the case of int, long, and boolean values, if there is no explicit specification of range, then the range includes all possible values of the type. In the case of float and double values, first a value is always chosen uniformly from the set of 2w values between 0.0 (inclusive) and 1.0 (exclusive), where w is 23 for float values and 52 for double values, such that adjacent values differ by 2−w (notice that this set is a subset of the set of all representable floating-point values between 0.0 (inclusive) and 1.0 (exclusive)); then if an explicit range was specified, then the chosen number is computationally scaled and translated so as to appear to have been chosen approximately uniformly from that explicit range.

Each method that returns a stream produces a stream of values each of which is chosen in the same manner as for a method that returns a single pseudorandomly chosen value. For example, if r implements RandomGenerator, then the method call r.ints(100) returns a stream of 100 int values. These are not necessarily the exact same values that would have been returned if instead r.nextInt() had been called 100 times; all that is guaranteed is that each value in the stream is chosen in a similar pseudorandom manner from the same range.

Every object that implements the RandomGenerator interface by using a pseudorandom algorithm is assumed to contain a finite amount of state. Using such an object to generate a pseudorandomly chosen value alters its state by computing a new state as a function of the current state, without reference to any information other than the current state. The number of distinct possible states of such an object is called its period. (Some implementations of the RandomGenerator interface may be truly random rather than pseudorandom, for example relying on the statistical behavior of a physical object to derive chosen values. Such implementations do not have a fixed period.)

As a rule, objects that implement the RandomGenerator interface need not be thread-safe. It is recommended that multithreaded applications use either ThreadLocalRandom or (preferably) pseudorandom number generators that implement the RandomGenerator.SplittableGenerator or RandomGenerator.JumpableGenerator interface.

Objects that implement RandomGenerator are typically not cryptographically secure. Consider instead using SecureRandom to get a cryptographically secure pseudorandom number generator for use by security-sensitive applications. Note, however, that SecureRandom does implement the RandomGenerator interface, so that instances of SecureRandom may be used interchangeably with other types of pseudorandom generators in applications that do not require a secure generator.

Unless explicit stated otherwise, the use of null for any method argument will cause a NullPointerException.

Since:
17

  • Nested Class Summary

    Nested Classes
    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
    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).
    static RandomGenerator
    getDefault()
    Returns a RandomGenerator meeting the minimal requirement of having an algorithm whose state bits are greater than or equal 64.
    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).
    static RandomGenerator
    of(String name)
    Returns an instance of RandomGenerator that utilizes the name algorithm.

  • Method Details

    • of

      static RandomGenerator of(String name)
      Returns an instance of RandomGenerator that utilizes the name algorithm.
      Parameters:
      name - Name of random number generator algorithm
      Returns:
      An instance of RandomGenerator
      Throws:
      NullPointerException - if name is null
      IllegalArgumentException - if the named algorithm is not found

    • getDefault

      static RandomGenerator getDefault()
      Returns a RandomGenerator meeting the minimal requirement of having an algorithm whose state bits are greater than or equal 64.
      Implementation Requirements:
      Since algorithms will improve over time, there is no guarantee that this method will return the same algorithm over time.

      The default implementation selects L32X64MixRandom.

      Returns:
      a RandomGenerator

    • isDeprecated

      default boolean isDeprecated()
      Return true if the implementation of RandomGenerator (algorithm) has been marked for deprecation.
      Implementation Requirements:
      The default implementation checks for the @Deprecated annotation.
      Implementation Note:
      Random number generator algorithms evolve over time; new algorithms will be introduced and old algorithms will lose standing. If an older algorithm is deemed unsuitable for continued use, it will be marked as deprecated to indicate that it may be removed at some point in the future.
      Returns:
      true if the implementation of RandomGenerator (algorithm) has been marked for deprecation

    • doubles

      default DoubleStream doubles()
      Returns an effectively unlimited stream of pseudorandomly chosen double values.
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextDouble().
      Implementation Note:
      It is permitted to implement this method in a manner equivalent to doubles (Long.MAX_VALUE).
      Returns:
      a stream of pseudorandomly chosen double values

    • doubles

      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).
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextDouble(randomNumberOrigin, randomNumberBound).
      Implementation Note:
      It is permitted to implement this method in a manner equivalent to doubles (Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).
      Parameters:
      randomNumberOrigin - the least value that can be produced
      randomNumberBound - the upper bound (exclusive) for each value produced
      Returns:
      a stream of pseudorandomly chosen double values, each between the specified origin (inclusive) and the specified bound (exclusive)
      Throws:
      IllegalArgumentException - if randomNumberOrigin is not finite, or randomNumberBound is not finite, or randomNumberOrigin is greater than or equal to randomNumberBound

    • doubles

      default DoubleStream doubles(long streamSize)
      Returns a stream producing the given streamSize number of pseudorandomly chosen double values.
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextDouble().
      Parameters:
      streamSize - the number of values to generate
      Returns:
      a stream of pseudorandomly chosen double values
      Throws:
      IllegalArgumentException - if streamSize is less than zero

    • doubles

      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).
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextDouble(randomNumberOrigin, randomNumberBound).
      Parameters:
      streamSize - the number of values to generate
      randomNumberOrigin - the least value that can be produced
      randomNumberBound - the upper bound (exclusive) for each value produced
      Returns:
      a stream of pseudorandomly chosen double values, each between the specified origin (inclusive) and the specified bound (exclusive)
      Throws:
      IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is not finite, or randomNumberBound is not finite, or randomNumberOrigin is greater than or equal to randomNumberBound

    • ints

      default IntStream ints()
      Returns an effectively unlimited stream of pseudorandomly chosen int values.
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextInt().
      Implementation Note:
      It is permitted to implement this method in a manner equivalent to ints (Long.MAX_VALUE).
      Returns:
      a stream of pseudorandomly chosen int values

    • ints

      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).
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextInt(randomNumberOrigin, randomNumberBound).
      Implementation Note:
      It is permitted to implement this method in a manner equivalent to ints (Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).
      Parameters:
      randomNumberOrigin - the least value that can be produced
      randomNumberBound - the upper bound (exclusive) for each value produced
      Returns:
      a stream of pseudorandomly chosen int values, each between the specified origin (inclusive) and the specified bound (exclusive)
      Throws:
      IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound

    • ints

      default IntStream ints(long streamSize)
      Returns a stream producing the given streamSize number of pseudorandomly chosen int values.
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextInt().
      Parameters:
      streamSize - the number of values to generate
      Returns:
      a stream of pseudorandomly chosen int values
      Throws:
      IllegalArgumentException - if streamSize is less than zero

    • ints

      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).
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextInt(randomNumberOrigin, randomNumberBound).
      Parameters:
      streamSize - the number of values to generate
      randomNumberOrigin - the least value that can be produced
      randomNumberBound - the upper bound (exclusive) for each value produced
      Returns:
      a stream of pseudorandomly chosen int values, each between the specified origin (inclusive) and the specified bound (exclusive)
      Throws:
      IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound

    • longs

      default LongStream longs()
      Returns an effectively unlimited stream of pseudorandomly chosen long values.
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextLong().
      Implementation Note:
      It is permitted to implement this method in a manner equivalent to longs (Long.MAX_VALUE).
      Returns:
      a stream of pseudorandomly chosen long values

    • longs

      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).
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextLong(randomNumberOrigin, randomNumberBound).
      Implementation Note:
      It is permitted to implement this method in a manner equivalent to longs (Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).
      Parameters:
      randomNumberOrigin - the least value that can be produced
      randomNumberBound - the upper bound (exclusive) for each value produced
      Returns:
      a stream of pseudorandomly chosen long values, each between the specified origin (inclusive) and the specified bound (exclusive)
      Throws:
      IllegalArgumentException - if randomNumberOrigin is greater than or equal to randomNumberBound

    • longs

      default LongStream longs(long streamSize)
      Returns a stream producing the given streamSize number of pseudorandomly chosen long values.
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextLong().
      Parameters:
      streamSize - the number of values to generate
      Returns:
      a stream of pseudorandomly chosen long values
      Throws:
      IllegalArgumentException - if streamSize is less than zero

    • longs

      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).
      Implementation Requirements:
      The default implementation produces a sequential stream that repeatedly calls nextLong(randomNumberOrigin, randomNumberBound).
      Parameters:
      streamSize - the number of values to generate
      randomNumberOrigin - the least value that can be produced
      randomNumberBound - the upper bound (exclusive) for each value produced
      Returns:
      a stream of pseudorandomly chosen long values, each between the specified origin (inclusive) and the specified bound (exclusive)
      Throws:
      IllegalArgumentException - if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound

    • nextBoolean

      default boolean nextBoolean()
      Returns a pseudorandomly chosen boolean value.

      The default implementation tests the high-order bit (sign bit) of a value produced by nextInt(), on the grounds that some algorithms for pseudorandom number generation produce values whose high-order bits have better statistical quality than the low-order bits.

      Implementation Requirements:
      The default implementation produces a result based on the sign bit of a number generated by nextInt().
      Returns:
      a pseudorandomly chosen boolean value

    • nextBytes

      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).
      Implementation Requirements:
      The default implementation produces results from repeated calls to nextLong().
      Implementation Note:
      Algorithm used to fill the byte array; 
      
           void nextBytes(byte[] bytes) {
               int i = 0;
               int len = bytes.length;
               for (int words = len >> 3; words--> 0; ) {
                   long rnd = nextLong();
                   for (int n = 8; n--> 0; rnd >>>= Byte.SIZE)
                       bytes[i++] = (byte)rnd;
               }
               if (i < len)
                   for (long rnd = nextLong(); i < len; rnd >>>= Byte.SIZE)
                       bytes[i++] = (byte)rnd;
           }
      Parameters:
      bytes - the byte array to fill with pseudorandom bytes
      Throws:
      NullPointerException - if bytes is null

    • nextFloat

      default float nextFloat()
      Returns a pseudorandom float value between zero (inclusive) and one (exclusive).
      Implementation Requirements:
      The default implementation uses the 24 high-order bits from a call to nextInt().
      Returns:
      a pseudorandom float value between zero (inclusive) and one (exclusive)

    • nextFloat

      default float nextFloat(float bound)
      Returns a pseudorandomly chosen float value between zero (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that bound is a positive finite float. Then invokes nextFloat(), scaling the result so that the final result lies between 0.0f (inclusive) and bound (exclusive).
      Parameters:
      bound - the upper bound (exclusive) for the returned value. Must be positive and finite
      Returns:
      a pseudorandomly chosen float value between zero (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if bound is not both positive and finite

    • nextFloat

      default float nextFloat(float origin, float bound)
      Returns a pseudorandomly chosen float value between the specified origin (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that origin and bound are positive finite floats. Then invokes nextFloat(), scaling and translating the result so that the final result lies between origin (inclusive) and bound (exclusive).
      Parameters:
      origin - the least value that can be returned
      bound - the upper bound (exclusive)
      Returns:
      a pseudorandomly chosen float value between the origin (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if origin is not finite, or bound is not finite, or origin is greater than or equal to bound

    • nextDouble

      default double nextDouble()
      Returns a pseudorandom double value between zero (inclusive) and one (exclusive).
      Implementation Requirements:
      The default implementation uses the 53 high-order bits from a call to nextLong().
      Returns:
      a pseudorandom double value between zero (inclusive) and one (exclusive)

    • nextDouble

      default double nextDouble(double bound)
      Returns a pseudorandomly chosen double value between zero (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that bound is a positive finite double. Then invokes nextDouble(), scaling the result so that the final result lies between 0.0 (inclusive) and bound (exclusive).
      Parameters:
      bound - the upper bound (exclusive) for the returned value. Must be positive and finite
      Returns:
      a pseudorandomly chosen double value between zero (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if bound is not both positive and finite

    • nextDouble

      default double nextDouble(double origin, double bound)
      Returns a pseudorandomly chosen double value between the specified origin (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that origin and bound are positive finite doubles. Then calls nextDouble(), scaling and translating the result so that the final result lies between origin (inclusive) and bound (exclusive).
      Parameters:
      origin - the least value that can be returned
      bound - the upper bound (exclusive) for the returned value
      Returns:
      a pseudorandomly chosen double value between the origin (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if origin is not finite, or bound is not finite, or origin is greater than or equal to bound

    • nextInt

      default int nextInt()
      Returns a pseudorandomly chosen int value.
      Implementation Requirements:
      The default implementation uses the 32 high-order bits from a call to nextLong().
      Returns:
      a pseudorandomly chosen int value

    • nextInt

      default int nextInt(int bound)
      Returns a pseudorandomly chosen int value between zero (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that bound is a positive int. Then invokes nextInt(), limiting the result to be greater than or equal zero and less than bound. If bound is a power of two then limiting is a simple masking operation. Otherwise, the result is re-calculated by invoking nextInt() until the result is greater than or equal zero and less than bound.
      Parameters:
      bound - the upper bound (exclusive) for the returned value. Must be positive.
      Returns:
      a pseudorandomly chosen int value between zero (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if bound is not positive

    • nextInt

      default int nextInt(int origin, int bound)
      Returns a pseudorandomly chosen int value between the specified origin (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that origin and bound are positive ints. Then invokes nextInt(), limiting the result to be greater that or equal origin and less than bound. If bound is a power of two then limiting is a simple masking operation. Otherwise, the result is re-calculated by invoking nextInt() until the result is greater than or equal origin and less than bound.
      Parameters:
      origin - the least value that can be returned
      bound - the upper bound (exclusive) for the returned value
      Returns:
      a pseudorandomly chosen int value between the origin (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if origin is greater than or equal to bound

    • nextLong

      long nextLong()
      Returns a pseudorandomly chosen long value.
      Returns:
      a pseudorandomly chosen long value

    • nextLong

      default long nextLong(long bound)
      Returns a pseudorandomly chosen long value between zero (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that bound is a positive long. Then invokes nextLong(), limiting the result to be greater than or equal zero and less than bound. If bound is a power of two then limiting is a simple masking operation. Otherwise, the result is re-calculated by invoking nextLong() until the result is greater than or equal zero and less than bound.
      Parameters:
      bound - the upper bound (exclusive) for the returned value. Must be positive.
      Returns:
      a pseudorandomly chosen long value between zero (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if bound is not positive

    • nextLong

      default long nextLong(long origin, long bound)
      Returns a pseudorandomly chosen long value between the specified origin (inclusive) and the specified bound (exclusive).
      Implementation Requirements:
      The default implementation checks that origin and bound are positive longs. Then invokes nextLong(), limiting the result to be greater than or equal origin and less than bound. If bound is a power of two then limiting is a simple masking operation. Otherwise, the result is re-calculated by invoking nextLong() until the result is greater than or equal origin and less than bound.
      Parameters:
      origin - the least value that can be returned
      bound - the upper bound (exclusive) for the returned value
      Returns:
      a pseudorandomly chosen long value between the origin (inclusive) and the bound (exclusive)
      Throws:
      IllegalArgumentException - if origin is greater than or equal to bound

    • nextGaussian

      default double nextGaussian()
      Returns a double value pseudorandomly chosen from a Gaussian (normal) distribution whose mean is 0 and whose standard deviation is 1.
      Implementation Requirements:
      The default implementation uses McFarland's fast modified ziggurat algorithm (largely table-driven, with rare cases handled by computation and rejection sampling). Walker's alias method for sampling a discrete distribution also plays a role.
      Returns:
      a double value pseudorandomly chosen from a Gaussian distribution

    • nextGaussian

      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.
      Implementation Requirements:
      The default implementation uses McFarland's fast modified ziggurat algorithm (largely table-driven, with rare cases handled by computation and rejection sampling). Walker's alias method for sampling a discrete distribution also plays a role.
      Parameters:
      mean - the mean of the Gaussian distribution to be drawn from
      stddev - the standard deviation (square root of the variance) of the Gaussian distribution to be drawn from
      Returns:
      a double value pseudorandomly chosen from the specified Gaussian distribution
      Throws:
      IllegalArgumentException - if stddev is negative

    • nextExponential

      default double nextExponential()
      Returns a nonnegative double value pseudorandomly chosen from an exponential distribution whose mean is 1.
      Implementation Requirements:
      The default implementation uses McFarland's fast modified ziggurat algorithm (largely table-driven, with rare cases handled by computation and rejection sampling). Walker's alias method for sampling a discrete distribution also plays a role.
      Returns:
      a nonnegative double value pseudorandomly chosen from an exponential distribution