Added in API level 1

UUID

class UUID : Comparable<UUID!>, Serializable

kotlin.Any
↳	java.util.UUID

A class that represents an immutable universally unique identifier (UUID). A UUID represents a 128-bit value.

There exist different variants of these global identifiers. The methods of this class are for manipulating the Leach-Salz variant, although the constructors allow the creation of any variant of UUID (described below).

The layout of a variant 2 (Leach-Salz) UUID is as follows: The most significant long consists of the following unsigned fields:

0xFFFFFFFF00000000 time_low
  0x00000000FFFF0000 time_mid
  0x000000000000F000 version
  0x0000000000000FFF time_hi

The least significant long consists of the following unsigned fields:

0xC000000000000000 variant
  0x3FFF000000000000 clock_seq
  0x0000FFFFFFFFFFFF node

The variant field contains a value which identifies the layout of the UUID. The bit layout described above is valid only for a UUID with a variant value of 2, which indicates the Leach-Salz variant.

The version field holds a value that describes the type of this UUID. There are four different basic types of UUIDs: time-based, DCE security, name-based, and randomly generated UUIDs. These types have a version value of 1, 2, 3 and 4, respectively.

For more information including algorithms used to create UUIDs, see RFC 4122: A Universally Unique IDentifier (UUID) URN Namespace, section 4.2 "Algorithms for Creating a Time-Based UUID".

Summary

Public constructors
`UUID(mostSigBits: Long, leastSigBits: Long)` Constructs a new `UUID` using the specified data.

Public methods
Int	`clockSequence()` The clock sequence value associated with this UUID.
Int	`compareTo(other: UUID!)` Compares this UUID with the specified UUID.
Boolean	`equals(other: Any?)` Compares this object to the specified object.
static UUID!	`fromString(name: String!)` Creates a `UUID` from the string standard representation as described in the `toString` method.
Long	`getLeastSignificantBits()` Returns the least 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()` Returns a hash code for this `UUID`.
static UUID!	`nameUUIDFromBytes(name: ByteArray!)` Static factory to retrieve a type 3 (name based) `UUID` based on the specified byte array.
Long	`node()` The node value associated with this UUID.
static UUID!	`randomUUID()` Static factory to retrieve a type 4 (pseudo randomly generated) UUID.
Long	`timestamp()` The timestamp value associated with this UUID.
String	`toString()` Returns a `String` object representing this `UUID`.
Int	`variant()` The variant number associated with this `UUID`.
Int	`version()` The version number associated with this `UUID`.

Public constructors

UUID

Added in API level 1

UUID(
    mostSigBits: Long, 
    leastSigBits: Long)

Constructs a new UUID using the specified data. mostSigBits is used for the most significant 64 bits of the UUID and leastSigBits becomes the least significant 64 bits of the UUID.

Parameters
`mostSigBits`	Long: The most significant bits of the `UUID`
`leastSigBits`	Long: The least significant bits of the `UUID`

Public methods

clockSequence

Added in API level 1

fun clockSequence(): Int

The clock sequence value associated with this UUID.

The 14 bit clock sequence value is constructed from the clock sequence field of this UUID. The clock sequence field is used to guarantee temporal uniqueness in a time-based UUID.

The clockSequence value is only meaningful in a time-based UUID, which has version type 1. If this UUID is not a time-based UUID then this method throws UnsupportedOperationException.

Return
`Int`	The clock sequence of this `UUID`

Exceptions
`java.lang.UnsupportedOperationException`	If this UUID is not a version 1 UUID

compareTo

Added in API level 1

fun compareTo(other: UUID!): Int

Compares this UUID with the specified UUID.

The first of two UUIDs is greater than the second if the most significant field in which the UUIDs differ is greater for the first UUID.

Parameters
`o`	the object to be compared.
`val`	`UUID` to which this `UUID` is to be compared

Return
`Int`	-1, 0 or 1 as this `UUID` is less than, equal to, or greater than `val`

Exceptions
`java.lang.NullPointerException`	if the specified object is null
`java.lang.ClassCastException`	if the specified object's type prevents it from being compared to this object.

equals

Added in API level 1

fun equals(other: Any?): Boolean

Compares this object to the specified object. The result is true if and only if the argument is not null, is a UUID object, has the same variant, and contains the same value, bit for bit, as this UUID.

Parameters
`obj`	The object to be compared

Return
`Boolean`	`true` if the objects are the same; `false` otherwise

fromString

Added in API level 1

static fun fromString(name: String!): UUID!

Creates a UUID from the string standard representation as described in the toString method.

Parameters
`name`	String!: A string that specifies a `UUID`

Return
`UUID!`	A `UUID` with the specified value

Exceptions
`java.lang.IllegalArgumentException`	If name does not conform to the string representation as described in `toString`

getLeastSignificantBits

Added in API level 1

fun getLeastSignificantBits(): Long

Returns the least significant 64 bits of this UUID's 128 bit value.

Return
`Long`	The least significant 64 bits of this UUID's 128 bit value

getMostSignificantBits

Added in API level 1

fun getMostSignificantBits(): Long

Returns the most significant 64 bits of this UUID's 128 bit value.

Return
`Long`	The most significant 64 bits of this UUID's 128 bit value

hashCode

Added in API level 1

fun hashCode(): Int

Returns a hash code for this UUID.

Return
`Int`	A hash code value for this `UUID`

nameUUIDFromBytes

Added in API level 1

static fun nameUUIDFromBytes(name: ByteArray!): UUID!

Static factory to retrieve a type 3 (name based) UUID based on the specified byte array.

Parameters
`name`	ByteArray!: A byte array to be used to construct a `UUID`

Return
`UUID!`	A `UUID` generated from the specified array

node

Added in API level 1

fun node(): Long

The node value associated with this UUID.

The 48 bit node value is constructed from the node field of this UUID. This field is intended to hold the IEEE 802 address of the machine that generated this UUID to guarantee spatial uniqueness.

The node value is only meaningful in a time-based UUID, which has version type 1. If this UUID is not a time-based UUID then this method throws UnsupportedOperationException.

Return
`Long`	The node value of this `UUID`

Exceptions
`java.lang.UnsupportedOperationException`	If this UUID is not a version 1 UUID

randomUUID

Added in API level 1

static fun randomUUID(): UUID!

Static factory to retrieve a type 4 (pseudo randomly generated) UUID. The UUID is generated using a cryptographically strong pseudo random number generator.

Return
`UUID!`	A randomly generated `UUID`

timestamp

Added in API level 1

fun timestamp(): Long

The timestamp value associated with this UUID.

The 60 bit timestamp value is constructed from the time_low, time_mid, and time_hi fields of this UUID. The resulting timestamp is measured in 100-nanosecond units since midnight, October 15, 1582 UTC.

The timestamp value is only meaningful in a time-based UUID, which has version type 1. If this UUID is not a time-based UUID then this method throws UnsupportedOperationException.

Return
`Long`	The timestamp of this `UUID`.

Exceptions
`java.lang.UnsupportedOperationException`	If this UUID is not a version 1 UUID

toString

Added in API level 1

fun toString(): String

Returns a String object representing this UUID.

The UUID string representation is as described by this BNF:

<code>UUID                   = &lt;time_low&gt; "-" &lt;time_mid&gt; "-"
                           &lt;time_high_and_version&gt; "-"
                           &lt;variant_and_sequence&gt; "-"
                           &lt;node&gt;
  time_low               = 4*&lt;hexOctet&gt;
  time_mid               = 2*&lt;hexOctet&gt;
  time_high_and_version  = 2*&lt;hexOctet&gt;
  variant_and_sequence   = 2*&lt;hexOctet&gt;
  node                   = 6*&lt;hexOctet&gt;
  hexOctet               = &lt;hexDigit&gt;&lt;hexDigit&gt;
  hexDigit               =
        "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
        | "a" | "b" | "c" | "d" | "e" | "f"
        | "A" | "B" | "C" | "D" | "E" | "F"
  </code>

Return
`String`	A string representation of this `UUID`

variant

Added in API level 1

fun variant(): Int

The variant number associated with this UUID. The variant number describes the layout of the UUID. The variant number has the following meaning:

0 Reserved for NCS backward compatibility
2 IETF RFC 4122 (Leach-Salz), used by this class
6 Reserved, Microsoft Corporation backward compatibility
7 Reserved for future definition

Return
`Int`	The variant number of this `UUID`

version

Added in API level 1

fun version(): Int

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

Return
`Int`	The version number of this `UUID`