Package io.github.pr0methean.betterrandom.seed

Enum DevRandomSeedGenerator

java.lang.Object

java.lang.Enum<DevRandomSeedGenerator>

io.github.pr0methean.betterrandom.seed.DevRandomSeedGenerator

All Implemented Interfaces:

SeedGenerator, Serializable, Comparable<DevRandomSeedGenerator>

public enum DevRandomSeedGenerator
extends Enum<DevRandomSeedGenerator>
implements SeedGenerator

RNG seed strategy that gets data from /dev/random on systems that provide it (e.g. Solaris/Linux). If /dev/random does not exist or is not accessible, a SeedException is thrown. If it didn't exist during a previous call to this method or to generateSeed(int), then for performance reasons, we assume for the rest of the JVM's lifespan that it still doesn't exist.

Author:

Daniel Dyer

Enum Constant Summary

Enum Constants

Enum Constant	Description
DEV_RANDOM_SEED_GENERATOR	Singleton instance.

Field Summary

Fields inherited from interface io.github.pr0methean.betterrandom.seed.SeedGenerator

EMPTY_SEED

Method Summary

Modifier and Type	Method	Description
void	generateSeed(byte[] randomSeed)	Generates a seed value for a random number generator in an existing array.
byte[]	generateSeed(int length)	Generates and returns a seed value for a random number generator as a new array.
boolean	isWorthTrying()	Returns true if we cannot determine quickly (i.e.
String	toString()	Returns "/dev/random".
static DevRandomSeedGenerator	valueOf(String name)	Returns the enum constant of this type with the specified name.
static DevRandomSeedGenerator[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

DEV_RANDOM_SEED_GENERATOR

public static final DevRandomSeedGenerator DEV_RANDOM_SEED_GENERATOR

Singleton instance.

Method Detail

values

public static DevRandomSeedGenerator[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DevRandomSeedGenerator c : DevRandomSeedGenerator.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DevRandomSeedGenerator valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

generateSeed

public void generateSeed(byte[] randomSeed)
                  throws SeedException

Description copied from interface: SeedGenerator

Generates a seed value for a random number generator in an existing array.

Specified by:

generateSeed in interface SeedGenerator

Parameters:

randomSeed - The array that is to be populated with the seed.

Throws:

SeedException - if /dev/random does not exist or is not accessible.

isWorthTrying

public boolean isWorthTrying()

Returns true if we cannot determine quickly (i.e. without I/O calls) that this SeedGenerator would throw a SeedException if generateSeed(int) or generateSeed(byte[]) were being called right now.

Specified by:

isWorthTrying in interface SeedGenerator

Returns:

true if this SeedGenerator will get as far as an I/O call or other slow operation in attempting to generate a seed immediately.

toString

public String toString()

Returns "/dev/random".

Overrides:

toString in class Enum<DevRandomSeedGenerator>

generateSeed

public byte[] generateSeed(int length)
                    throws SeedException

Generates and returns a seed value for a random number generator as a new array.

Specified by:

generateSeed in interface SeedGenerator

Parameters:

length - The length of the seed to generate (in bytes).

Returns:

A byte array containing the seed data.

Throws:

SeedException - If a seed cannot be generated for any reason.