com.fasterxml.uuid

Class Generators

java.lang.Object

com.fasterxml.uuid.Generators

public class Generators
extends Object

Root factory class for constructing UUID generators.

Since:

3.0

Author:

tatu

Field Summary

Fields

Modifier and Type	Field and Description
protected static EthernetAddress	_preferredIfAddr The hardware address of the egress network interface.
protected static UUIDTimer	_sharedTimer If no explicit timer (and synchronizer it implicitly uses) is specified, we will create and use a single lazily-constructed timer, which uses in-JVM synchronization but no external file-based syncing.

Constructor Summary

Constructors

Constructor and Description
Generators()

Method Summary

Modifier and Type	Method and Description
static TimeBasedGenerator	defaultTimeBasedGenerator() Factory method for constructing UUID generator that generates UUID using variant 1 (time+location based).
static NameBasedGenerator	nameBasedGenerator() Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 5, but without using a namespace.
static NameBasedGenerator	nameBasedGenerator(UUID namespace) Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 5, with specified namespace (or without one if null is specified).
static NameBasedGenerator	nameBasedGenerator(UUID namespace, MessageDigest digester) Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 3 or 5, with specified namespace (or without one if null is specified), using specified digester.
static RandomBasedGenerator	randomBasedGenerator() Factory method for constructing UUID generator that uses default (shared) random number generator for constructing UUIDs according to standard method number 4.
static RandomBasedGenerator	randomBasedGenerator(Random rnd) Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 4.
static TimeBasedEpochGenerator	timeBasedEpochGenerator() Factory method for constructing UUID generator that generates UUID using version 7 (Unix Epoch time+random based).
static TimeBasedEpochGenerator	timeBasedEpochGenerator(Random random) Factory method for constructing UUID generator that generates UUID using version 7 (time+random based), using specified Ethernet address as the location part of UUID.
static TimeBasedGenerator	timeBasedGenerator() Factory method for constructing UUID generator that generates UUID using version 1 (time+location based).
static TimeBasedGenerator	timeBasedGenerator(EthernetAddress ethernetAddress) Factory method for constructing UUID generator that generates UUID using version 1 (time+location based), using specified Ethernet address as the location part of UUID.
static TimeBasedGenerator	timeBasedGenerator(EthernetAddress ethernetAddress, TimestampSynchronizer sync) Factory method for constructing UUID generator that generates UUID using version 1 (time+location based), using specified Ethernet address as the location part of UUID, and specified synchronizer (which may add additional restrictions to guarantee system-wide uniqueness).
static TimeBasedGenerator	timeBasedGenerator(EthernetAddress ethernetAddress, UUIDTimer timer) Factory method for constructing UUID generator that generates UUID using version 1 (time+location based), using specified Ethernet address as the location part of UUID, and specified UUIDTimer instance (which includes embedded synchronizer that defines synchronization behavior).
static TimeBasedReorderedGenerator	timeBasedReorderedGenerator() Factory method for constructing UUID generator that generates UUID using version 6 (time+location based, reordered for DB locality).
static TimeBasedReorderedGenerator	timeBasedReorderedGenerator(EthernetAddress ethernetAddress) Factory method for constructing UUID generator that generates UUID using version 6 (time+location based, reordered for DB locality), using specified Ethernet address as the location part of UUID.
static TimeBasedReorderedGenerator	timeBasedReorderedGenerator(EthernetAddress ethernetAddress, UUIDTimer timer) Factory method for constructing UUID generator that generates UUID using version 6 (time+location based, reordered for DB locality), using specified Ethernet address as the location part of UUID, and specified UUIDTimer instance (which includes embedded synchronizer that defines synchronization behavior).

Methods inherited from class java.lang.Object

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

Field Detail

_sharedTimer

protected static UUIDTimer _sharedTimer

If no explicit timer (and synchronizer it implicitly uses) is specified, we will create and use a single lazily-constructed timer, which uses in-JVM synchronization but no external file-based syncing.

_preferredIfAddr

protected static EthernetAddress _preferredIfAddr

The hardware address of the egress network interface.

Constructor Detail

Generators

public Generators()

Method Detail

randomBasedGenerator

public static RandomBasedGenerator randomBasedGenerator()

Factory method for constructing UUID generator that uses default (shared) random number generator for constructing UUIDs according to standard method number 4.

randomBasedGenerator

public static RandomBasedGenerator randomBasedGenerator(Random rnd)

Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 4.

nameBasedGenerator

public static NameBasedGenerator nameBasedGenerator()

Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 5, but without using a namespace. Digester to use will be SHA-1 as recommened by UUID spec.

nameBasedGenerator

public static NameBasedGenerator nameBasedGenerator(UUID namespace)

Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 5, with specified namespace (or without one if null is specified). Digester to use will be SHA-1 as recommened by UUID spec.

Parameters:

namespace - UUID that represents namespace to use; see NameBasedGenerator for 'standard' namespaces specified by UUID specs

nameBasedGenerator

public static NameBasedGenerator nameBasedGenerator(UUID namespace,
                                                    MessageDigest digester)

Factory method for constructing UUID generator that uses specified random number generator for constructing UUIDs according to standard method number 3 or 5, with specified namespace (or without one if null is specified), using specified digester. If digester is passed as null, a SHA-1 digester will be constructed.

Parameters:

namespace - UUID that represents namespace to use; see NameBasedGenerator for 'standard' namespaces specified by UUID specs

digester - Digester to use; should be a MD5 or SHA-1 digester.

timeBasedEpochGenerator

public static TimeBasedEpochGenerator timeBasedEpochGenerator()

Factory method for constructing UUID generator that generates UUID using version 7 (Unix Epoch time+random based).

timeBasedEpochGenerator

public static TimeBasedEpochGenerator timeBasedEpochGenerator(Random random)

Factory method for constructing UUID generator that generates UUID using version 7 (time+random based), using specified Ethernet address as the location part of UUID. No additional external synchronization is used.

defaultTimeBasedGenerator

public static TimeBasedGenerator defaultTimeBasedGenerator()

Factory method for constructing UUID generator that generates UUID using variant 1 (time+location based). This method will use the ethernet address of the interface that routes to the default gateway, or if that cannot be found, then the address of an indeterminately selected non-loopback interface. For most simple and common networking configurations this will be the most appropriate address to use. The default interface is determined by the calling EthernetAddress.fromPreferredInterface() method. Note that this will only identify the preferred interface once: if you have a complex network setup where your outbound routes/interfaces may change dynamically. If you want your UUIDs to accurately reflect a deterministic selection of network interface, you should instead use a generator implementation that uses an explicitly specified address, such as timeBasedGenerator(EthernetAddress).

Since:

4.2

timeBasedGenerator

public static TimeBasedGenerator timeBasedGenerator()

Factory method for constructing UUID generator that generates UUID using version 1 (time+location based). Since no Ethernet address is passed, a bogus broadcast address will be constructed for purpose of UUID generation; usually it is better to instead access one of host's NIC addresses using EthernetAddress.fromInterface() which will use one of available MAC (Ethernet) addresses available.

timeBasedGenerator

public static TimeBasedGenerator timeBasedGenerator(EthernetAddress ethernetAddress)

Factory method for constructing UUID generator that generates UUID using version 1 (time+location based), using specified Ethernet address as the location part of UUID. No additional external synchronization is used.

timeBasedGenerator

public static TimeBasedGenerator timeBasedGenerator(EthernetAddress ethernetAddress,
                                                    TimestampSynchronizer sync)

Factory method for constructing UUID generator that generates UUID using version 1 (time+location based), using specified Ethernet address as the location part of UUID, and specified synchronizer (which may add additional restrictions to guarantee system-wide uniqueness).

Parameters:

ethernetAddress - (optional) MAC address to use; if null, a transient random address is generated.

See Also:

FileBasedTimestampSynchronizer

timeBasedGenerator

public static TimeBasedGenerator timeBasedGenerator(EthernetAddress ethernetAddress,
                                                    UUIDTimer timer)

Factory method for constructing UUID generator that generates UUID using version 1 (time+location based), using specified Ethernet address as the location part of UUID, and specified UUIDTimer instance (which includes embedded synchronizer that defines synchronization behavior).

timeBasedReorderedGenerator

public static TimeBasedReorderedGenerator timeBasedReorderedGenerator()

Factory method for constructing UUID generator that generates UUID using version 6 (time+location based, reordered for DB locality). Since no Ethernet address is passed, a bogus broadcast address will be constructed for purpose of UUID generation; usually it is better to instead access one of host's NIC addresses using EthernetAddress.fromInterface() which will use one of available MAC (Ethernet) addresses available.

timeBasedReorderedGenerator

public static TimeBasedReorderedGenerator timeBasedReorderedGenerator(EthernetAddress ethernetAddress)

Factory method for constructing UUID generator that generates UUID using version 6 (time+location based, reordered for DB locality), using specified Ethernet address as the location part of UUID. No additional external synchronization is used.

timeBasedReorderedGenerator

public static TimeBasedReorderedGenerator timeBasedReorderedGenerator(EthernetAddress ethernetAddress,
                                                                      UUIDTimer timer)

Factory method for constructing UUID generator that generates UUID using version 6 (time+location based, reordered for DB locality), using specified Ethernet address as the location part of UUID, and specified UUIDTimer instance (which includes embedded synchronizer that defines synchronization behavior).