Package org.apache.hadoop.hbase.util

Class Random64

java.lang.Object

org.apache.hadoop.hbase.util.Random64

@Private
public class Random64
extends Object

An instance of this class is used to generate a stream of pseudorandom numbers. The class uses a 64-bit seed, which is modified using a linear congruential formula. see https://en.wikipedia.org/wiki/Linear_congruential_generator

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	addend
private static final long	multiplier
private long	seed
private static final AtomicLong	seedUniquifier

Constructor Summary

Constructors

Constructor	Description
Random64()
Random64(long seed)

Method Summary

Modifier and Type	Method	Description
static void	main(String[] args)	Random64 is a pseudorandom algorithm(LCG).
private long	next64(int bits)
void	nextBytes(byte[] bytes)
long	nextLong()
private static long	seedUniquifier()	Copy from Random#seedUniquifier()

Methods inherited from class java.lang.Object

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

Field Details

multiplier

private static final long multiplier

See Also:

• Constant Field Values

addend

private static final long addend

See Also:

• Constant Field Values

seedUniquifier

private static final AtomicLong seedUniquifier

seed

private long seed

Constructor Details

Random64

public Random64()

Random64

public Random64(long seed)

Method Details

seedUniquifier

private static long seedUniquifier()

Copy from Random#seedUniquifier()

nextLong

public long nextLong()

nextBytes

public void nextBytes(byte[] bytes)

next64

private long next64(int bits)

main

public static void main(String[] args)

Random64 is a pseudorandom algorithm(LCG). Therefore, we will get same sequence if seeds are the same. This main will test how many calls nextLong() it will get the same seed. We do not need to save all numbers (that is too large). We could save once every 100000 calls nextLong(). If it get a same seed, we can detect this by calling nextLong() 100000 times continuously.