Added in API level 1

UUID

class UUID : Serializable, Comparable<UUID!>

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