com.fasterxml.uuid.impl

Class RandomBasedGenerator

java.lang.Object

com.fasterxml.uuid.UUIDGenerator

com.fasterxml.uuid.NoArgGenerator

com.fasterxml.uuid.impl.RandomBasedGenerator

public class RandomBasedGenerator
extends NoArgGenerator

Implementation of UUID generator that uses generation method 4.

Note on random number generation when using SecureRandom for random number generation: the first time SecureRandom object is used, there is noticeable delay between calling the method and getting the reply. This is because SecureRandom has to initialize itself to reasonably random state. Thus, if you want to lessen delay, it may be be a good idea to either get the first random UUID asynchronously from a separate thread, or to use the other generateRandomBasedUUID passing a previously initialized SecureRandom instance.

Since:

3.0

Field Summary

Fields

Modifier and Type	Field and Description
protected Random	_random Random number generator that this generator uses.
protected boolean	_secureRandom Looks like SecureRandom implementation is more efficient using single call access (compared to basic Random), so let's use that knowledge to our benefit.
protected static Random	_sharedRandom Default shared random number generator, used if no random number generator is explicitly specified for instance

Constructor Summary

Constructors

Constructor and Description
RandomBasedGenerator(Random rnd)

Method Summary

Modifier and Type	Method and Description
protected static long	_toLong(byte[] buffer, int offset)
UUID	generate()
UUIDType	getType() Accessor for determining type of UUIDs (version) that this generator instance will produce.

Methods inherited from class java.lang.Object

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

Field Detail

_sharedRandom

protected static Random _sharedRandom

Default shared random number generator, used if no random number generator is explicitly specified for instance

_random

protected final Random _random

Random number generator that this generator uses.

_secureRandom

protected final boolean _secureRandom

Looks like SecureRandom implementation is more efficient using single call access (compared to basic Random), so let's use that knowledge to our benefit.

Constructor Detail

RandomBasedGenerator

public RandomBasedGenerator(Random rnd)

Parameters:

rnd - Random number generator to use for generating UUIDs; if null, shared default generator is used. Note that it is strongly recommend to use a good (pseudo) random number generator; for example, JDK's SecureRandom.

Method Detail

getType

public UUIDType getType()

Description copied from class: UUIDGenerator

Accessor for determining type of UUIDs (version) that this generator instance will produce.

Specified by:

getType in class UUIDGenerator

generate

public UUID generate()

Specified by:

generate in class NoArgGenerator

_toLong

protected static final long _toLong(byte[] buffer,
                                    int offset)