Class RandomDataImpl

  • All Implemented Interfaces:
    java.io.Serializable, RandomData

    @Deprecated
    public class RandomDataImpl
    extends java.lang.Object
    implements RandomData, java.io.Serializable
    Deprecated.
    to be removed in 4.0. Use RandomDataGenerator instead
    Generates random deviates and other random data using a RandomGenerator instance to generate non-secure data and a SecureRandom instance to provide data for the nextSecureXxx methods. If no RandomGenerator is provided in the constructor, the default is to use a Well19937c generator. To plug in a different implementation, either implement RandomGenerator directly or extend AbstractRandomGenerator.

    Supports reseeding the underlying pseudo-random number generator (PRNG). The SecurityProvider and Algorithm used by the SecureRandom instance can also be reset.

    For details on the default PRNGs, see Random and SecureRandom.

    Usage Notes:

    • Instance variables are used to maintain RandomGenerator and SecureRandom instances used in data generation. Therefore, to generate a random sequence of values or strings, you should use just one RandomDataGenerator instance repeatedly.
    • The "secure" methods are *much* slower. These should be used only when a cryptographically secure random sequence is required. A secure random sequence is a sequence of pseudo-random values which, in addition to being well-dispersed (so no subsequence of values is an any more likely than other subsequence of the the same length), also has the additional property that knowledge of values generated up to any point in the sequence does not make it any easier to predict subsequent values.
    • When a new RandomDataGenerator is created, the underlying random number generators are not initialized. If you do not explicitly seed the default non-secure generator, it is seeded with the current time in milliseconds plus the system identity hash code on first use. The same holds for the secure generator. If you provide a RandomGenerator to the constructor, however, this generator is not reseeded by the constructor nor is it reseeded on first use.
    • The reSeed and reSeedSecure methods delegate to the corresponding methods on the underlying RandomGenerator and SecureRandom instances. Therefore, reSeed(long) fully resets the initial state of the non-secure random number generator (so that reseeding with a specific value always results in the same subsequent random sequence); whereas reSeedSecure(long) does not reinitialize the secure random number generator (so secure sequences started with calls to reseedSecure(long) won't be identical).
    • This implementation is not synchronized. The underlying RandomGenerator or SecureRandom instances are not protected by synchronization and are not guaranteed to be thread-safe. Therefore, if an instance of this class is concurrently utilized by multiple threads, it is the responsibility of client code to synchronize access to seeding and data generation methods.

    See Also:
    Serialized Form
    • Constructor Summary

      Constructors 
      Constructor Description
      RandomDataImpl()
      Deprecated.
      Construct a RandomDataImpl, using a default random generator as the source of randomness.
      RandomDataImpl​(RandomGenerator rand)
      Deprecated.
      Construct a RandomDataImpl using the supplied RandomGenerator as the source of (non-secure) random data.
    • Method Summary

      All Methods Instance Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      (package private) RandomDataGenerator getDelegate()
      Deprecated.
      To be removed in 4.0.
      double nextBeta​(double alpha, double beta)
      Deprecated.
      Generates a random value from the Beta Distribution.
      int nextBinomial​(int numberOfTrials, double probabilityOfSuccess)
      Deprecated.
      Generates a random value from the Binomial Distribution.
      double nextCauchy​(double median, double scale)
      Deprecated.
      Generates a random value from the Cauchy Distribution.
      double nextChiSquare​(double df)
      Deprecated.
      Generates a random value from the ChiSquare Distribution.
      double nextExponential​(double mean)
      Deprecated.
      Generates a random value from the exponential distribution with specified mean.
      double nextF​(double numeratorDf, double denominatorDf)
      Deprecated.
      Generates a random value from the F Distribution.
      double nextGamma​(double shape, double scale)
      Deprecated.
      Generates a random value from the Gamma Distribution.
      double nextGaussian​(double mu, double sigma)
      Deprecated.
      Generates a random value from the Normal (or Gaussian) distribution with specified mean and standard deviation.
      java.lang.String nextHexString​(int len)
      Deprecated.
      Generates a random string of hex characters of length len.
      int nextHypergeometric​(int populationSize, int numberOfSuccesses, int sampleSize)
      Deprecated.
      Generates a random value from the Hypergeometric Distribution.
      int nextInt​(int lower, int upper)
      Deprecated.
      Generates a uniformly distributed random integer between lower and upper (endpoints included).
      int nextInversionDeviate​(IntegerDistribution distribution)
      Deprecated.
      use the distribution's sample() method
      double nextInversionDeviate​(RealDistribution distribution)
      Deprecated.
      use the distribution's sample() method
      long nextLong​(long lower, long upper)
      Deprecated.
      Generates a uniformly distributed random long integer between lower and upper (endpoints included).
      int nextPascal​(int r, double p)
      Deprecated.
      Generates a random value from the Pascal Distribution.
      int[] nextPermutation​(int n, int k)
      Deprecated.
      Generates an integer array of length k whose entries are selected randomly, without repetition, from the integers 0, ..., n - 1 (inclusive).
      long nextPoisson​(double mean)
      Deprecated.
      Generates a random value from the Poisson distribution with the given mean.
      java.lang.Object[] nextSample​(java.util.Collection<?> c, int k)
      Deprecated.
      Returns an array of k objects selected randomly from the Collection c.
      java.lang.String nextSecureHexString​(int len)
      Deprecated.
      Generates a random string of hex characters from a secure random sequence.
      int nextSecureInt​(int lower, int upper)
      Deprecated.
      Generates a uniformly distributed random integer between lower and upper (endpoints included) from a secure random sequence.
      long nextSecureLong​(long lower, long upper)
      Deprecated.
      Generates a uniformly distributed random long integer between lower and upper (endpoints included) from a secure random sequence.
      double nextT​(double df)
      Deprecated.
      Generates a random value from the T Distribution.
      double nextUniform​(double lower, double upper)
      Deprecated.
      Generates a uniformly distributed random value from the open interval (lower, upper) (i.e., endpoints excluded).
      double nextUniform​(double lower, double upper, boolean lowerInclusive)
      Deprecated.
      Generates a uniformly distributed random value from the interval (lower, upper) or the interval [lower, upper).
      double nextWeibull​(double shape, double scale)
      Deprecated.
      Generates a random value from the Weibull Distribution.
      int nextZipf​(int numberOfElements, double exponent)
      Deprecated.
      Generates a random value from the Zipf Distribution.
      void reSeed()
      Deprecated.
      Reseeds the random number generator with System.currentTimeMillis() + System.identityHashCode(this)).
      void reSeed​(long seed)
      Deprecated.
      Reseeds the random number generator with the supplied seed.
      void reSeedSecure()
      Deprecated.
      Reseeds the secure random number generator with the current time in milliseconds.
      void reSeedSecure​(long seed)
      Deprecated.
      Reseeds the secure random number generator with the supplied seed.
      void setSecureAlgorithm​(java.lang.String algorithm, java.lang.String provider)
      Deprecated.
      Sets the PRNG algorithm for the underlying SecureRandom instance using the Security Provider API.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • serialVersionUID

        private static final long serialVersionUID
        Deprecated.
        Serializable version identifier
        See Also:
        Constant Field Values
      • delegate

        private final RandomDataGenerator delegate
        Deprecated.
        RandomDataGenerator delegate
    • Constructor Detail

      • RandomDataImpl

        public RandomDataImpl()
        Deprecated.
        Construct a RandomDataImpl, using a default random generator as the source of randomness.

        The default generator is a Well19937c seeded with System.currentTimeMillis() + System.identityHashCode(this)). The generator is initialized and seeded on first use.

      • RandomDataImpl

        public RandomDataImpl​(RandomGenerator rand)
        Deprecated.
        Construct a RandomDataImpl using the supplied RandomGenerator as the source of (non-secure) random data.
        Parameters:
        rand - the source of (non-secure) random data (may be null, resulting in the default generator)
        Since:
        1.1
    • Method Detail

      • getDelegate

        @Deprecated
        RandomDataGenerator getDelegate()
        Deprecated.
        To be removed in 4.0.
        Returns:
        the delegate object.
      • nextHexString

        public java.lang.String nextHexString​(int len)
                                       throws NotStrictlyPositiveException
        Deprecated.
        Generates a random string of hex characters of length len.

        The generated string will be random, but not cryptographically secure. To generate cryptographically secure strings, use RandomData.nextSecureHexString(int).

        Algorithm Description: hex strings are generated using a 2-step process.

        1. len / 2 + 1 binary bytes are generated using the underlying Random
        2. Each binary byte is translated into 2 hex digits

        Specified by:
        nextHexString in interface RandomData
        Parameters:
        len - the desired string length.
        Returns:
        the random string.
        Throws:
        NotStrictlyPositiveException - if len <= 0.
      • nextInt

        public int nextInt​(int lower,
                           int upper)
                    throws NumberIsTooLargeException
        Deprecated.
        Generates a uniformly distributed random integer between lower and upper (endpoints included).

        The generated integer will be random, but not cryptographically secure. To generate cryptographically secure integer sequences, use RandomData.nextSecureInt(int, int).

        Specified by:
        nextInt in interface RandomData
        Parameters:
        lower - lower bound for generated integer
        upper - upper bound for generated integer
        Returns:
        a random integer greater than or equal to lower and less than or equal to upper
        Throws:
        NumberIsTooLargeException - if lower >= upper
      • nextLong

        public long nextLong​(long lower,
                             long upper)
                      throws NumberIsTooLargeException
        Deprecated.
        Generates a uniformly distributed random long integer between lower and upper (endpoints included).

        The generated long integer values will be random, but not cryptographically secure. To generate cryptographically secure sequences of longs, use RandomData.nextSecureLong(long, long).

        Specified by:
        nextLong in interface RandomData
        Parameters:
        lower - lower bound for generated long integer
        upper - upper bound for generated long integer
        Returns:
        a random long integer greater than or equal to lower and less than or equal to upper
        Throws:
        NumberIsTooLargeException - if lower >= upper
      • nextSecureHexString

        public java.lang.String nextSecureHexString​(int len)
                                             throws NotStrictlyPositiveException
        Deprecated.
        Generates a random string of hex characters from a secure random sequence.

        If cryptographic security is not required, use RandomData.nextHexString(int).

        Algorithm Description: hex strings are generated in 40-byte segments using a 3-step process.

        1. 20 random bytes are generated using the underlying SecureRandom.
        2. SHA-1 hash is applied to yield a 20-byte binary digest.
        3. Each byte of the binary digest is converted to 2 hex digits.

        Specified by:
        nextSecureHexString in interface RandomData
        Parameters:
        len - the length of the string to be generated
        Returns:
        a random string of hex characters of length len
        Throws:
        NotStrictlyPositiveException - if len <= 0
      • nextSecureInt

        public int nextSecureInt​(int lower,
                                 int upper)
                          throws NumberIsTooLargeException
        Deprecated.
        Generates a uniformly distributed random integer between lower and upper (endpoints included) from a secure random sequence.

        Sequences of integers generated using this method will be cryptographically secure. If cryptographic security is not required, RandomData.nextInt(int, int) should be used instead of this method.

        Definition: Secure Random Sequence

        Specified by:
        nextSecureInt in interface RandomData
        Parameters:
        lower - lower bound for generated integer
        upper - upper bound for generated integer
        Returns:
        a random integer greater than or equal to lower and less than or equal to upper.
        Throws:
        NumberIsTooLargeException - if lower >= upper.
      • nextSecureLong

        public long nextSecureLong​(long lower,
                                   long upper)
                            throws NumberIsTooLargeException
        Deprecated.
        Generates a uniformly distributed random long integer between lower and upper (endpoints included) from a secure random sequence.

        Sequences of long values generated using this method will be cryptographically secure. If cryptographic security is not required, RandomData.nextLong(long, long) should be used instead of this method.

        Definition: Secure Random Sequence

        Specified by:
        nextSecureLong in interface RandomData
        Parameters:
        lower - lower bound for generated integer
        upper - upper bound for generated integer
        Returns:
        a random long integer greater than or equal to lower and less than or equal to upper.
        Throws:
        NumberIsTooLargeException - if lower >= upper.
      • nextPoisson

        public long nextPoisson​(double mean)
                         throws NotStrictlyPositiveException
        Deprecated.
        Generates a random value from the Poisson distribution with the given mean.

        Definition: Poisson Distribution

        Algorithm Description:

        • For small means, uses simulation of a Poisson process using Uniform deviates, as described here. The Poisson process (and hence value returned) is bounded by 1000 * mean.
        • For large means, uses the rejection algorithm described in
          Devroye, Luc. (1981).The Computer Generation of Poisson Random Variables Computing vol. 26 pp. 197-207.

        Specified by:
        nextPoisson in interface RandomData
        Parameters:
        mean - the mean of the Poisson distribution
        Returns:
        a random value following the specified Poisson distribution
        Throws:
        NotStrictlyPositiveException - if mean <= 0.
      • nextGaussian

        public double nextGaussian​(double mu,
                                   double sigma)
                            throws NotStrictlyPositiveException
        Deprecated.
        Generates a random value from the Normal (or Gaussian) distribution with specified mean and standard deviation.

        Definition: Normal Distribution

        Specified by:
        nextGaussian in interface RandomData
        Parameters:
        mu - the mean of the distribution
        sigma - the standard deviation of the distribution
        Returns:
        a random value following the specified Gaussian distribution
        Throws:
        NotStrictlyPositiveException - if sigma <= 0.
      • nextExponential

        public double nextExponential​(double mean)
                               throws NotStrictlyPositiveException
        Deprecated.
        Generates a random value from the exponential distribution with specified mean.

        Definition: Exponential Distribution

        Algorithm Description: Uses the Algorithm SA (Ahrens) from p. 876 in: [1]: Ahrens, J. H. and Dieter, U. (1972). Computer methods for sampling from the exponential and normal distributions. Communications of the ACM, 15, 873-882.

        Specified by:
        nextExponential in interface RandomData
        Parameters:
        mean - the mean of the distribution
        Returns:
        a random value following the specified exponential distribution
        Throws:
        NotStrictlyPositiveException - if mean <= 0.
      • nextUniform

        public double nextUniform​(double lower,
                                  double upper)
                           throws NumberIsTooLargeException,
                                  NotFiniteNumberException,
                                  NotANumberException
        Deprecated.
        Generates a uniformly distributed random value from the open interval (lower, upper) (i.e., endpoints excluded).

        Definition: Uniform Distribution lower and upper - lower are the location and scale parameters, respectively.

        Algorithm Description: scales the output of Random.nextDouble(), but rejects 0 values (i.e., will generate another random double if Random.nextDouble() returns 0). This is necessary to provide a symmetric output interval (both endpoints excluded).

        Specified by:
        nextUniform in interface RandomData
        Parameters:
        lower - the exclusive lower bound of the support
        upper - the exclusive upper bound of the support
        Returns:
        a uniformly distributed random value between lower and upper (exclusive)
        Throws:
        NumberIsTooLargeException - if lower >= upper
        NotFiniteNumberException - if one of the bounds is infinite
        NotANumberException - if one of the bounds is NaN
      • nextUniform

        public double nextUniform​(double lower,
                                  double upper,
                                  boolean lowerInclusive)
                           throws NumberIsTooLargeException,
                                  NotFiniteNumberException,
                                  NotANumberException
        Deprecated.
        Generates a uniformly distributed random value from the interval (lower, upper) or the interval [lower, upper). The lower bound is thus optionally included, while the upper bound is always excluded.

        Definition: Uniform Distribution lower and upper - lower are the location and scale parameters, respectively.

        Algorithm Description: if the lower bound is excluded, scales the output of Random.nextDouble(), but rejects 0 values (i.e., will generate another random double if Random.nextDouble() returns 0). This is necessary to provide a symmetric output interval (both endpoints excluded).

        Specified by:
        nextUniform in interface RandomData
        Parameters:
        lower - the lower bound of the support
        upper - the exclusive upper bound of the support
        lowerInclusive - true if the lower bound is inclusive
        Returns:
        uniformly distributed random value in the (lower, upper) interval, if lowerInclusive is false, or in the [lower, upper) interval, if lowerInclusive is true
        Throws:
        NumberIsTooLargeException - if lower >= upper
        NotFiniteNumberException - if one of the bounds is infinite
        NotANumberException - if one of the bounds is NaN
        Since:
        3.0
      • nextBeta

        public double nextBeta​(double alpha,
                               double beta)
        Deprecated.
        Generates a random value from the Beta Distribution. This implementation uses inversion to generate random values.
        Parameters:
        alpha - first distribution shape parameter
        beta - second distribution shape parameter
        Returns:
        random value sampled from the beta(alpha, beta) distribution
        Since:
        2.2
      • nextBinomial

        public int nextBinomial​(int numberOfTrials,
                                double probabilityOfSuccess)
        Deprecated.
        Generates a random value from the Binomial Distribution. This implementation uses inversion to generate random values.
        Parameters:
        numberOfTrials - number of trials of the Binomial distribution
        probabilityOfSuccess - probability of success of the Binomial distribution
        Returns:
        random value sampled from the Binomial(numberOfTrials, probabilityOfSuccess) distribution
        Since:
        2.2
      • nextCauchy

        public double nextCauchy​(double median,
                                 double scale)
        Deprecated.
        Generates a random value from the Cauchy Distribution. This implementation uses inversion to generate random values.
        Parameters:
        median - the median of the Cauchy distribution
        scale - the scale parameter of the Cauchy distribution
        Returns:
        random value sampled from the Cauchy(median, scale) distribution
        Since:
        2.2
      • nextChiSquare

        public double nextChiSquare​(double df)
        Deprecated.
        Generates a random value from the ChiSquare Distribution. This implementation uses inversion to generate random values.
        Parameters:
        df - the degrees of freedom of the ChiSquare distribution
        Returns:
        random value sampled from the ChiSquare(df) distribution
        Since:
        2.2
      • nextF

        public double nextF​(double numeratorDf,
                            double denominatorDf)
                     throws NotStrictlyPositiveException
        Deprecated.
        Generates a random value from the F Distribution. This implementation uses inversion to generate random values.
        Parameters:
        numeratorDf - the numerator degrees of freedom of the F distribution
        denominatorDf - the denominator degrees of freedom of the F distribution
        Returns:
        random value sampled from the F(numeratorDf, denominatorDf) distribution
        Throws:
        NotStrictlyPositiveException - if numeratorDf <= 0 or denominatorDf <= 0.
        Since:
        2.2
      • nextGamma

        public double nextGamma​(double shape,
                                double scale)
                         throws NotStrictlyPositiveException
        Deprecated.

        Generates a random value from the Gamma Distribution.

        This implementation uses the following algorithms:

        For 0 < shape < 1:
        Ahrens, J. H. and Dieter, U., Computer methods for sampling from gamma, beta, Poisson and binomial distributions. Computing, 12, 223-246, 1974.

        For shape >= 1:
        Marsaglia and Tsang, A Simple Method for Generating Gamma Variables. ACM Transactions on Mathematical Software, Volume 26 Issue 3, September, 2000.

        Parameters:
        shape - the median of the Gamma distribution
        scale - the scale parameter of the Gamma distribution
        Returns:
        random value sampled from the Gamma(shape, scale) distribution
        Throws:
        NotStrictlyPositiveException - if shape <= 0 or scale <= 0.
        Since:
        2.2
      • nextWeibull

        public double nextWeibull​(double shape,
                                  double scale)
                           throws NotStrictlyPositiveException
        Deprecated.
        Generates a random value from the Weibull Distribution. This implementation uses inversion to generate random values.
        Parameters:
        shape - the shape parameter of the Weibull distribution
        scale - the scale parameter of the Weibull distribution
        Returns:
        random value sampled from the Weibull(shape, size) distribution
        Throws:
        NotStrictlyPositiveException - if shape <= 0 or scale <= 0.
        Since:
        2.2
      • nextZipf

        public int nextZipf​(int numberOfElements,
                            double exponent)
                     throws NotStrictlyPositiveException
        Deprecated.
        Generates a random value from the Zipf Distribution. This implementation uses inversion to generate random values.
        Parameters:
        numberOfElements - the number of elements of the ZipfDistribution
        exponent - the exponent of the ZipfDistribution
        Returns:
        random value sampled from the Zipf(numberOfElements, exponent) distribution
        Throws:
        NotStrictlyPositiveException - if numberOfElements <= 0 or exponent <= 0.
        Since:
        2.2
      • reSeed

        public void reSeed​(long seed)
        Deprecated.
        Reseeds the random number generator with the supplied seed.

        Will create and initialize if null.

        Parameters:
        seed - the seed value to use
      • reSeedSecure

        public void reSeedSecure()
        Deprecated.
        Reseeds the secure random number generator with the current time in milliseconds.

        Will create and initialize if null.

      • reSeedSecure

        public void reSeedSecure​(long seed)
        Deprecated.
        Reseeds the secure random number generator with the supplied seed.

        Will create and initialize if null.

        Parameters:
        seed - the seed value to use
      • reSeed

        public void reSeed()
        Deprecated.
        Reseeds the random number generator with System.currentTimeMillis() + System.identityHashCode(this)).
      • setSecureAlgorithm

        public void setSecureAlgorithm​(java.lang.String algorithm,
                                       java.lang.String provider)
                                throws java.security.NoSuchAlgorithmException,
                                       java.security.NoSuchProviderException
        Deprecated.
        Sets the PRNG algorithm for the underlying SecureRandom instance using the Security Provider API. The Security Provider API is defined in Java Cryptography Architecture API Specification & Reference.

        USAGE NOTE: This method carries significant overhead and may take several seconds to execute.

        Parameters:
        algorithm - the name of the PRNG algorithm
        provider - the name of the provider
        Throws:
        java.security.NoSuchAlgorithmException - if the specified algorithm is not available
        java.security.NoSuchProviderException - if the specified provider is not installed
      • nextPermutation

        public int[] nextPermutation​(int n,
                                     int k)
                              throws NotStrictlyPositiveException,
                                     NumberIsTooLargeException
        Deprecated.
        Generates an integer array of length k whose entries are selected randomly, without repetition, from the integers 0, ..., n - 1 (inclusive).

        Generated arrays represent permutations of n taken k at a time.

        Uses a 2-cycle permutation shuffle. The shuffling process is described here.

        Specified by:
        nextPermutation in interface RandomData
        Parameters:
        n - the domain of the permutation
        k - the size of the permutation
        Returns:
        a random k-permutation of n, as an array of integers
        Throws:
        NotStrictlyPositiveException - if k <= 0.
        NumberIsTooLargeException - if k > n.
      • nextSample

        public java.lang.Object[] nextSample​(java.util.Collection<?> c,
                                             int k)
                                      throws NotStrictlyPositiveException,
                                             NumberIsTooLargeException
        Deprecated.
        Returns an array of k objects selected randomly from the Collection c.

        Sampling from c is without replacement; but if c contains identical objects, the sample may include repeats. If all elements of c are distinct, the resulting object array represents a Simple Random Sample of size k from the elements of c.

        Algorithm Description: Uses a 2-cycle permutation shuffle to generate a random permutation of c.size() and then returns the elements whose indexes correspond to the elements of the generated permutation. This technique is described, and proven to generate random samples here

        Specified by:
        nextSample in interface RandomData
        Parameters:
        c - the collection to be sampled
        k - the size of the sample
        Returns:
        a random sample of k elements from c
        Throws:
        NotStrictlyPositiveException - if k <= 0.
        NumberIsTooLargeException - if k > c.size().
      • nextInversionDeviate

        @Deprecated
        public double nextInversionDeviate​(RealDistribution distribution)
                                    throws MathIllegalArgumentException
        Deprecated.
        use the distribution's sample() method
        Generate a random deviate from the given distribution using the inversion method.
        Parameters:
        distribution - Continuous distribution to generate a random value from
        Returns:
        a random value sampled from the given distribution
        Throws:
        MathIllegalArgumentException - if the underlynig distribution throws one
        Since:
        2.2
      • nextInversionDeviate

        @Deprecated
        public int nextInversionDeviate​(IntegerDistribution distribution)
                                 throws MathIllegalArgumentException
        Deprecated.
        use the distribution's sample() method
        Generate a random deviate from the given distribution using the inversion method.
        Parameters:
        distribution - Integer distribution to generate a random value from
        Returns:
        a random value sampled from the given distribution
        Throws:
        MathIllegalArgumentException - if the underlynig distribution throws one
        Since:
        2.2