IT. Expert System.

All Implemented Interfaces:

Serializable, Comparable<UUID>

public final class UUID
extends Object
implements Serializable, Comparable<UUID>

Since:

1.5

See Also:

Serialized Form

• Constructor Summary

  Constructors

  Constructor and Description
  UUID(long mostSigBits, long leastSigBits) Constructs an instance with the specified bits.

• Method Summary

  Methods

  Modifier and Type	Method and Description
  int	clockSequence() The clock sequence value of the version 1, variant 2 UUID as per RFC 4122.
  int	compareTo(UUID uuid) Compares this UUID to the specified UUID.
  boolean	equals(Object object) Compares this UUID to another object for equality.
  static UUID	fromString(String uuid) Parses a UUID string with the format defined by toString().
  long	getLeastSignificantBits() The 64 least significant bits of the UUID.
  long	getMostSignificantBits() The 64 most significant bits of the UUID.
  int	hashCode() Returns a hash value for this UUID that is consistent with the equals(Object) method.
  static UUID	nameUUIDFromBytes(byte[] name) Generates a variant 2, version 3 (name-based, MD5-hashed) UUID as per RFC 4122.
  long	node() The node value of the version 1, variant 2 UUID as per RFC 4122.
  static UUID	randomUUID() Generates a variant 2, version 4 (randomly generated number) UUID as per RFC 4122.
  long	timestamp() The timestamp value of the version 1, variant 2 UUID as per RFC 4122.
  String	toString() Returns a string representation of this UUID in the following format, as per RFC 4122.
  int	variant() The variant of the UUID as per RFC 4122.
  int	version() The version of the variant 2 UUID as per RFC 4122.

  • Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

• Constructor Detail

  • UUID

    public UUID(long mostSigBits,
        long leastSigBits)

    Constructs an instance with the specified bits.

    Parameters:

    mostSigBits - The 64 most significant bits of the UUID.

    leastSigBits - The 64 least significant bits of the UUID.

• Method Detail

  • randomUUID

    public static UUID randomUUID()

    Generates a variant 2, version 4 (randomly generated number) UUID as per RFC 4122.

    Returns:

    an UUID instance.

  • nameUUIDFromBytes

    public static UUID nameUUIDFromBytes(byte[] name)

    Generates a variant 2, version 3 (name-based, MD5-hashed) UUID as per RFC 4122.

    Parameters:

    name - the name used as byte array to create an UUID.

    Returns:

    an UUID instance.

  • fromString

    public static UUID fromString(String uuid)

    Parses a UUID string with the format defined by toString().

    Parameters:

    uuid - the UUID string to parse.

    Returns:

    an UUID instance.

    Throws:

    NullPointerException - if uuid is null.

    IllegalArgumentException - if uuid is not formatted correctly.

  • getLeastSignificantBits

    public long getLeastSignificantBits()

    The 64 least significant bits of the UUID.

    Returns:

    the 64 least significant bits.

  • getMostSignificantBits

    public long getMostSignificantBits()

    The 64 most significant bits of the UUID.

    Returns:

    the 64 most significant bits.

  • version

    public int version()

    The version of the variant 2 UUID as per RFC 4122. If the variant is not 2, then the version will be 0.

    • 1 - Time-based UUID
    • 2 - DCE Security UUID
    • 3 - Name-based with MD5 hashing UUID (nameUUIDFromBytes(byte[]))
    • 4 - Randomly generated UUID (randomUUID())
    • 5 - Name-based with SHA-1 hashing UUID

    Returns:

    an int value.

  • variant

    public int variant()

    The variant of the UUID as per RFC 4122.

    • 0 - Reserved for NCS compatibility
    • 2 - RFC 4122/Leach-Salz
    • 6 - Reserved for Microsoft Corporation compatibility
    • 7 - Reserved for future use

    Returns:

    an int value.

  • timestamp

    public long timestamp()

    The timestamp value of the version 1, variant 2 UUID as per RFC 4122.

    Returns:

    a long value.

    Throws:

    UnsupportedOperationException - if version() is not 1.

  • clockSequence

    public int clockSequence()

    The clock sequence value of the version 1, variant 2 UUID as per RFC 4122.

    Returns:

    a long value.

    Throws:

    UnsupportedOperationException - if version() is not 1.

  • node

    public long node()

    The node value of the version 1, variant 2 UUID as per RFC 4122.

    Returns:

    a long value.

    Throws:

    UnsupportedOperationException - if version() is not 1.

  • compareTo

    public int compareTo(UUID uuid)

    Compares this UUID to the specified UUID. The natural ordering of UUIDs is based upon the value of the bits from most significant to least significant.

    Specified by:

    compareTo in interface Comparable<UUID>

    Parameters:

    uuid - the UUID to compare to.

    Returns:

    a value of -1, 0 or 1 if this UUID is less than, equal to or greater than uuid.

  • equals

    public boolean equals(Object object)

    Compares this UUID to another object for equality. If object is not null, is a UUID instance, and all bits are equal, then true is returned.

    Overrides:

    equals in class Object

    Parameters:

    object - the Object to compare to.

    Returns:

    true if this UUID is equal to object or false if not.

    See Also:

    Object.hashCode()

  • hashCode

    public int hashCode()

    Returns a hash value for this UUID that is consistent with the equals(Object) method.

    Overrides:

    hashCode in class Object

    Returns:

    an int value.

    See Also:

    Object.equals(java.lang.Object)

  • toString

    public String toString()

    Returns a string representation of this UUID in the following format, as per RFC 4122.

                UUID                   = time-low "-" time-mid "-"
                                         time-high-and-version "-"
                                         clock-seq-and-reserved
                                         clock-seq-low "-" node
                time-low               = 4hexOctet
                time-mid               = 2hexOctet
                time-high-and-version  = 2hexOctet
                clock-seq-and-reserved = hexOctet
                clock-seq-low          = hexOctet
                node                   = 6hexOctet
                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 Object

    Returns:

    a String instance.