java.util
Class Random

java.lang.Object
  |
  +--java.util.Random

public class Random

extends Object

A Random class generates a stream of pseudo-random numbers.

To create a new random number generator, use one of the following methods:

     new Random()       
     new Random(long seed)
 

The form new Random() initializes the generator to a value based on the current time. The form new Random(long seed) seeds the random number generator with a specific initial value; use this if an application requires a repeatable stream of pseudo-random numbers.

The random number generator uses a 48-bit seed, which is modified using a linear congruential formula. See Donald Knuth, The Art of Computer Programming, Volume 2, Section 3.2.1. The generator's seed can be reset with the following method:

    setSeed(long seed)
 

To create a pseudo-random number, use one of the following functions:

    nextInt()
    nextLong()
    nextFloat()
    nextDouble()
    nextGaussian()
 

See Also:

Math.random()

Constructor Summary

Random()
Creates a new random number generator.

Random(long seed)
Creates a new random number generator using a single long seed.

Method Summary

double	nextDouble() Generates a pseudorandom uniformally distributed double value between 0.0 and 1.0.
float	nextFloat() Generates a pseudorandom uniformally distributed float value between 0.0 and 1.0.
double	nextGaussian() Generates a pseudorandom Gaussian distributed double value with mean 0.0 and standard deviation 1.0.
int	nextInt() Generates a pseudorandom uniformally distributed int value.
long	nextLong() Generate a pseudorandom uniformally distributed long value.
void	setSeed(long seed) Sets the seed of the random number generator using a single long seed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Random

public Random()

Creates a new random number generator. Its seed will be initialized to a value based on the current time.

Random

public Random(long seed)

Creates a new random number generator using a single long seed.

Parameters:

seed - the initial seed

See Also:

setSeed(long)

Method Detail

setSeed

public void setSeed(long seed)

Sets the seed of the random number generator using a single long seed.

Parameters:

seed - the initial seed

nextInt

public int nextInt()

Generates a pseudorandom uniformally distributed int value.

Returns:

an integer value.

nextLong

public long nextLong()

Generate a pseudorandom uniformally distributed long value.

Returns:

A long integer value

nextFloat

public float nextFloat()

Generates a pseudorandom uniformally distributed float value between 0.0 and 1.0.

Returns:

a float between 0.0 and 1.0 .

nextDouble

public double nextDouble()

Generates a pseudorandom uniformally distributed double value between 0.0 and 1.0.

Returns:

a float between 0.0 and 1.0 .

nextGaussian

public double nextGaussian()

Generates a pseudorandom Gaussian distributed double value with mean 0.0 and standard deviation 1.0.

Returns:

a Gaussian distributed double.