Class AbstractRandomGenerator

Method Details

• clear

  public void clear()

  Clears the cache used by the default implementation of nextGaussian(). Implementations that do not override the default implementation of nextGaussian should call this method in the implementation of setSeed(long)

• setSeed

  public void setSeed(int seed)

  Sets the seed of the underlying random number generator using an int seed.

  Sequences of values generated starting with the same seeds should be identical.

  Specified by:

  setSeed in interface RandomGenerator

  Parameters:

  seed - the seed value

• setSeed

  public void setSeed(int[] seed)

  Sets the seed of the underlying random number generator using an int array seed.

  Sequences of values generated starting with the same seeds should be identical.

  Specified by:

  setSeed in interface RandomGenerator

  Parameters:

  seed - the seed value

• setSeed

  public abstract void setSeed(long seed)

  Sets the seed of the underlying random number generator using a long seed. Sequences of values generated starting with the same seeds should be identical.

  Implementations that do not override the default implementation of nextGaussian should include a call to clear() in the implementation of this method.

  Specified by:

  setSeed in interface RandomGenerator

  Parameters:

  seed - the seed value

• nextBytes

  public void nextBytes(byte[] bytes)

  Generates random bytes and places them into a user-supplied byte array. The number of random bytes produced is equal to the length of the byte array.

  The default implementation fills the array with bytes extracted from random integers generated using nextInt().

  Specified by:

  nextBytes in interface RandomGenerator

  Parameters:

  bytes - the non-null byte array in which to put the random bytes

• nextInt

  public int nextInt()

  Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence. All 2³² possible int values should be produced with (approximately) equal probability.

  The default implementation provided here returns

   (int) (nextDouble() * Integer.MAX_VALUE)
   

  Specified by:

  nextInt in interface RandomGenerator

  Returns:

  the next pseudorandom, uniformly distributed int value from this random number generator's sequence

• nextInt

  public int nextInt(int n)

  Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

  The default implementation returns

   (int) (nextDouble() * n
   

  Specified by:

  nextInt in interface RandomGenerator

  Parameters:

  n - the bound on the random number to be returned. Must be positive.

  Returns:

  a pseudorandom, uniformly distributed int value between 0 (inclusive) and n (exclusive).

  Throws:

  NotStrictlyPositiveException - if n <= 0.

• nextLong

  public long nextLong()

  Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence. All 2⁶⁴ possible long values should be produced with (approximately) equal probability.

  The default implementation returns

   (long) (nextDouble() * Long.MAX_VALUE)
   

  Specified by:

  nextLong in interface RandomGenerator

  Returns:

  the next pseudorandom, uniformly distributed long value from this random number generator's sequence

• nextBoolean

  public boolean nextBoolean()

  Returns the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence.

  The default implementation returns

   nextDouble() invalid input: '<'= 0.5
   

  Specified by:

  nextBoolean in interface RandomGenerator

  Returns:

  the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence

• nextFloat

  public float nextFloat()

  Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.

  The default implementation returns

   (float) nextDouble() 
   

  Specified by:

  nextFloat in interface RandomGenerator

  Returns:

  the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence

• nextDouble

  public abstract double nextDouble()

  Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.

  This method provides the underlying source of random data used by the other methods.

  Specified by:

  nextDouble in interface RandomGenerator

  Returns:

  the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence

• nextGaussian

  public double nextGaussian()

  Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.

  The default implementation uses the Polar Method due to G.E.P. Box, M.E. Muller and G. Marsaglia, as described in D. Knuth, The Art of Computer Programming, 3.4.1C.

  The algorithm generates a pair of independent random values. One of these is cached for reuse, so the full algorithm is not executed on each activation. Implementations that do not override this method should make sure to call clear() to clear the cached value in the implementation of setSeed(long).

  Specified by:

  nextGaussian in interface RandomGenerator

  Returns:

  the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence