UUID

java.lang.Object
- memeid.UUID

All Implemented Interfaces:

java.lang.Comparable<UUID>

Direct Known Subclasses:

UUID.UnknownVersion, UUID.V1, UUID.V2, UUID.V3, UUID.V4, UUID.V5
```
public class UUID
extends java.lang.Object
implements java.lang.Comparable<UUID>
```
A class that represents an immutable universally unique identifier (UUID). A UUID represents a 128-bit value.

See Also:

RFC-4122

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`UUID.UnknownVersion` Not standard-version UUIDs.
`static class`	`UUID.V1` Version 1 UUIDs are those generated using a timestamp and the MAC address of the computer on which it was generated.
`static class`	`UUID.V2` DCE Security version, with embedded POSIX UIDs.
`static class`	`UUID.V3` Version 3 UUIDs are those generated by hashing a namespace identifier and name using MD5 as the hashing algorithm.
`static class`	`UUID.V4` Version 4 UUIDs are those generated using random numbers.
`static class`	`UUID.V5` Version 5 UUIDs are those generated by hashing a namespace identifier and name using SHA-1 as the hashing algorithm.

Field Summary

Fields
Modifier and Type Field and Description

static byte[] nibbles

static UUID NIL
The nil UUID is special form of UUID that is specified to have all 128 bits set to zero.

Fields
Modifier and Type	Field and Description
`static byte[]`	`nibbles`
`static UUID`	`NIL` The nil UUID is special form of UUID that is specified to have all 128 bits set to zero.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`java.util.UUID`	`asJava()` Returns this `UUID` as a `UUID`.
`java.util.Optional<UUID.V1>`	`asV1()` Returns this `UUID` as a `UUID.V1` if versions match; otherwise, returns `Optional.empty()`.
`java.util.Optional<UUID.V2>`	`asV2()` Returns this `UUID` as a `UUID.V2` if versions match; otherwise, returns `Optional.empty()`.
`java.util.Optional<UUID.V3>`	`asV3()` Returns this `UUID` as a `UUID.V3` if versions match; otherwise, returns `Optional.empty()`.
`java.util.Optional<UUID.V4>`	`asV4()` Returns this `UUID` as a `UUID.V4` if versions match; otherwise, returns `Optional.empty()`.
`java.util.Optional<UUID.V5>`	`asV5()` Returns this `UUID` as a `UUID.V5` if versions match; otherwise, returns `Optional.empty()`.
`int`	`compareTo(UUID o)`
`boolean`	`equals(java.lang.Object obj)`
`static UUID`	`from(long msb, long lsb)` Creates a valid `UUID` from two `long` values representing the most/least significant bits.
`static UUID`	`fromString(java.lang.String name)` Creates a `UUID` from the string standard representation as described in the `toString()` method.
`static UUID`	`fromUUID(java.util.UUID juuid)` Creates a valid `UUID` from a `UUID`.
`long`	`getLeastSignificantBits()` Returns the most significant 64 bits of this UUID's 128 bit value.
`long`	`getMostSignificantBits()` Returns the most significant 64 bits of this UUID's 128 bit value.
`int`	`hashCode()`
`boolean`	`isNil()` Returns `true` if this UUID is a NIL UUID; otherwise, returns `false`.
`boolean`	`isV1()` Returns `true` if this UUID is a `UUID.V1`; otherwise, returns `false`.
`boolean`	`isV2()` Returns `true` if this UUID is a `UUID.V2`; otherwise, returns `false`.
`boolean`	`isV3()` Returns `true` if this UUID is a `UUID.V3`; otherwise, returns `false`.
`boolean`	`isV4()` Returns `true` if this UUID is a `UUID.V4`; otherwise, returns `false`.
`boolean`	`isV5()` Returns `true` if this UUID is a `UUID.V5`; otherwise, returns `false`.
`java.lang.String`	`toString()` Returns a `String` object representing this `UUID`.
`int`	`variant()` The variant field determines the layout of the `UUID`.
`int`	`version()` The version number associated with this `UUID`.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - nibbles
```
public static final byte[] nibbles
```
  - NIL
```
public static final UUID NIL
```
    The nil UUID is special form of UUID that is specified to have all 128 bits set to zero.
    
    See Also:
    
    RFC-4122
- Method Detail
  - from
```
public static UUID from(long msb,
                        long lsb)
```
    Creates a valid UUID from two long values representing the most/least significant bits.
    
    Parameters:
    
    msb - Most significant bit in long representation
    
    lsb - Least significant bit in long representation
    
    Returns:
    
    a new UUID constructed from msb and lsb
  - fromUUID
```
public static UUID fromUUID(java.util.UUID juuid)
```
    Creates a valid UUID from a UUID.
    
    Parameters:
    
    juuid - the UUID
    
    Returns:
    
    a valid UUID created from a UUID
  - fromString
```
public static UUID fromString(java.lang.String name)
```
    Creates a UUID from the string standard representation as described in the toString() method.
    
    Parameters:
    
    name - A string that specifies a UUID
    
    Returns:
    
    A UUID with the specified value
    
    Throws:
    
    java.lang.IllegalArgumentException - If name does not conform to the string representation as described in toString()
  - getMostSignificantBits
```
public long getMostSignificantBits()
```
    Returns the most significant 64 bits of this UUID's 128 bit value.
    
    Returns:
    
    The most significant 64 bits of this UUID's 128 bit value
  - getLeastSignificantBits
```
public long getLeastSignificantBits()
```
    Returns the most significant 64 bits of this UUID's 128 bit value.
    
    Returns:
    
    The most significant 64 bits of this UUID's 128 bit value
  - variant
```
public int variant()
```
    The variant field determines the layout of the UUID.
    The variant field consists of a variable number of the most significant bits of octet 8 of the UUID.
    The variant number has the following meaning:
    - '''0''': Reserved for NCS backward compatibility
    - '''2''': RFC-4122
    - '''6''': Reserved, Microsoft Corporation backward compatibility
    - '''7''': Reserved for future definition
    Interoperability, in any form, with variants other than the one defined here is not guaranteed, and is not likely to be an issue in practice.
    Returns:
    
    The variant of this UUID
    
    See Also:
    
    RFC-4122
  - version
```
public int version()
```
    The version number associated with this UUID. The version number describes how this UUID was generated.
    The version number has the following meaning:
    - '''1''': Time-based UUID
    - '''2''': DCE security UUID
    - '''3''': Name-based UUID
    - '''4''': Randomly generated UUID
    - '''5''': The name-based version that uses SHA-1 hashing
    Returns:
    
    The version number of this UUID
    
    See Also:
    
    RFC-4122
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Overrides:
    
    equals in class java.lang.Object
  - compareTo
```
public int compareTo(UUID o)
```
    Specified by:
    
    compareTo in interface java.lang.Comparable<UUID>
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Returns a String object representing this UUID.
    The UUID string representation is as described by this BNF:
    UUID = <time_low> "-" <time_mid> "-" <time_high_and_version> "-" <variant_and_sequence> "-" <node> time_low = 4*<hexOctet> time_mid = 2*<hexOctet> time_high_and_version = 2*<hexOctet> variant_and_sequence = 2*<hexOctet> node = 6*<hexOctet> hexOctet = <hexDigit><hexDigit> hexDigit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" | "a" | "b" | "c" | "d" | "e" | "f" | "A" | "B" | "C" | "D" | "E" | "F"
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    A string representation of this UUID
  - asJava
```
public java.util.UUID asJava()
```
    Returns this UUID as a UUID.
    
    Returns:
    
    this UUID as a UUID
  - asV1
```
public java.util.Optional<UUID.V1> asV1()
```
    Returns this UUID as a UUID.V1 if versions match; otherwise, returns Optional.empty().
    
    Returns:
    
    this UUID as a UUID.V1 if versions match; otherwise, returns Optional.empty().
  - asV2
```
public java.util.Optional<UUID.V2> asV2()
```
    Returns this UUID as a UUID.V2 if versions match; otherwise, returns Optional.empty().
    
    Returns:
    
    this UUID as a UUID.V2 if versions match; otherwise, returns Optional.empty().
  - asV3
```
public java.util.Optional<UUID.V3> asV3()
```
    Returns this UUID as a UUID.V3 if versions match; otherwise, returns Optional.empty().
    
    Returns:
    
    this UUID as a UUID.V3 if versions match; otherwise, returns Optional.empty().
  - asV4
```
public java.util.Optional<UUID.V4> asV4()
```
    Returns this UUID as a UUID.V4 if versions match; otherwise, returns Optional.empty().
    
    Returns:
    
    this UUID as a UUID.V4 if versions match; otherwise, returns Optional.empty().
  - asV5
```
public java.util.Optional<UUID.V5> asV5()
```
    Returns this UUID as a UUID.V5 if versions match; otherwise, returns Optional.empty().
    
    Returns:
    
    this UUID as a UUID.V5 if versions match; otherwise, returns Optional.empty().
  - isNil
```
public boolean isNil()
```
    Returns true if this UUID is a NIL UUID; otherwise, returns false.
    
    Returns:
    
    true if this UUID is a NIL UUID; false otherwise
  - isV1
```
public boolean isV1()
```
    Returns true if this UUID is a UUID.V1; otherwise, returns false.
    
    Returns:
    
    true if this UUID is a UUID.V1; false otherwise
  - isV2
```
public boolean isV2()
```
    Returns true if this UUID is a UUID.V2; otherwise, returns false.
    
    Returns:
    
    true if this UUID is a UUID.V2; false otherwise
  - isV3
```
public boolean isV3()
```
    Returns true if this UUID is a UUID.V3; otherwise, returns false.
    
    Returns:
    
    true if this UUID is a UUID.V3; false otherwise
  - isV4
```
public boolean isV4()
```
    Returns true if this UUID is a UUID.V4; otherwise, returns false.
    
    Returns:
    
    true if this UUID is a UUID.V4; false otherwise
  - isV5
```
public boolean isV5()
```
    Returns true if this UUID is a UUID.V5; otherwise, returns false.
    
    Returns:
    
    true if this UUID is a UUID.V5; false otherwise

Class UUID

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

nibbles

NIL

Method Detail

from

fromUUID

fromString

getMostSignificantBits

getLeastSignificantBits

variant

version

equals

compareTo

hashCode

toString

asJava

asV1

asV2

asV3

asV4

asV5

isNil

isV1

isV2

isV3

isV4

isV5