Module com.github.f4b6a3.uuid

Package com.github.f4b6a3.uuid.util.internal

Class RandomUtil

java.lang.Object

com.github.f4b6a3.uuid.util.internal.RandomUtil

public final class RandomUtil
extends Object

Utility class that wraps a shared SecureRandom and provides new instances of SecureRandom.

Field Summary

Fields

Modifier and Type	Field	Description
protected static SecureRandom	SHARED_RANDOM

Method Summary

Modifier and Type	Method	Description
static SecureRandom	newSecureRandom()	Returns a new instance of SecureRandom.
static int	nextInt()
static long	nextLong()

Methods inherited from class java.lang.Object

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

Field Detail

SHARED_RANDOM

protected static final SecureRandom SHARED_RANDOM

Method Detail

nextInt

public static int nextInt()

nextLong

public static long nextLong()

newSecureRandom

public static SecureRandom newSecureRandom()

Returns a new instance of SecureRandom.

It tries to create an instance with the algorithm name specified in the system property `uuidcreator.securerandom` or in the environment variable `UUIDCREATOR_SECURERANDOM`. If the algorithm name is not supported by the runtime, it returns an instance with the default algorithm.

It can be useful to make use of SHA1PRNG or DRBG as a non-blocking source of random bytes. The SHA1PRNG algorithm is default on operating systems that don't have '/dev/random', e.g., on Windows. The DRBG algorithm is available in JDK 9+.

To control the algorithm used by this method, use the system property `uuidcreator.securerandom` or the environment variable `UUIDCREATOR_SECURERANDOM` as in examples below.

System property:

 # Use the the algorithm SHA1PRNG for SecureRandom
 -Duuidcreator.securerandom="SHA1PRNG"
 
 # Use the the algorithm DRBG for SecureRandom (JDK9+)
 -Duuidcreator.securerandom="DRBG"
 

Environment variable:

 # Use the the algorithm SHA1PRNG for SecureRandom
 export UUIDCREATOR_SECURERANDOM="SHA1PRNG"
 
 # Use the the algorithm DRBG for SecureRandom (JDK9+)
 export UUIDCREATOR_SECURERANDOM="DRBG"
 

Returns:

a new SecureRandom.