java.util
Class UUID
- Comparable<T>, Serializable
This class represents a 128-bit UUID value.
There are several types of UUID, and while this class can be used to store
them, only the Leach-Salz (variant 2) UUID specified in RFC-4122 will
give meaningful results from the method calls.
See: http://tools.ietf.org/html/4122 for the details
The format of a Leach-Salz (variant 2) time-based (version 1) UUID
is as follows:
time_low - upper 32 bits of the most significant 64 bits,
this is the least-significant part of the timestamp.
time_mid - bits 16-31 of the most significant 64 bits,
this is the middle portion of the timestamp.
version - bits 8-15 of the most significant 64 bits.
time_hi - bits 0-7 of the most significant 64 bits,
the most significant portion of the timestamp.
clock_and_reserved - bits 48-63 of the least significant 64 bits.
a variable number of bits hold the variant
(see the spec)
node identifier - bits 0-47 of the least signficant 64 bits.
These fields are valid only for version 1, in the remaining versions,
only the version and variant fields are set, all others are used for data.
UUID(long mostSigBits, long leastSigBits)- Constructs a new UUID.
|
int | clockSequence()- Returns the clock-sequence value of this UUID.
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int | compareTo(UUID o)- Compare this UUID to another.
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boolean | equals(Object obj)- Compare a (UUID) object to this one
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static UUID | fromString(String name)- Creates a UUID object from a Sting representation.
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long | getLeastSignificantBits()- Returns the least significant 64 bits of the UUID as a
long.
|
long | getMostSignificantBits()- Returns the most significant 64 bits of the UUID as a
long.
|
int | hashCode()- Returns a hash of this UUID.
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static UUID | nameUUIDFromBytes(byte[] name)- Creates a UUID version 3 object (name based with MD5 hashing)
from a series of bytes representing a name.
|
long | node()- Returns the 48-bit node value in a long.
|
static UUID | randomUUID()- Generate a Leach-Salz (Variant 2) randomly generated (version 4)
UUID.
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long | timestamp()- Returns the 60-bit timestamp value of the UUID in a long.
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String | toString()- Returns a String representation of the UUID.
|
int | variant()- Returns the variant of the UUID
This may be:
0 = Reserved for NCS backwards-compatibility
2 = Leach-Salz (supports the other methods in this class)
6 = Reserved for Microsoft backwards-compatibility
7 = (reserved for future use)
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int | version()- Returns the version # of the UUID.
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clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait |
UUID
public UUID(long mostSigBits,
long leastSigBits) Constructs a new UUID.
clockSequence
public int clockSequence()
Returns the clock-sequence value of this UUID.
This field only exists in a time-based (version 1) UUID.
compareTo
public int compareTo(UUID o)
Compare this UUID to another.
The comparison is performed as between two 128-bit integers.
- -1 if this <32val, 0 if they are equal, 1 if this > val.
fromString
public static UUID fromString(String name)
Creates a UUID object from a Sting representation.
For the format of the string,
getLeastSignificantBits
public long getLeastSignificantBits()
Returns the least significant 64 bits of the UUID as a long.
getMostSignificantBits
public long getMostSignificantBits()
Returns the most significant 64 bits of the UUID as a long.
nameUUIDFromBytes
public static UUID nameUUIDFromBytes(byte[] name)
Creates a UUID version 3 object (name based with MD5 hashing)
from a series of bytes representing a name.
node
public long node()
Returns the 48-bit node value in a long.
This field only exists in a time-based (version 1) UUID.
randomUUID
public static UUID randomUUID()
Generate a Leach-Salz (Variant 2) randomly generated (version 4)
UUID.
timestamp
public long timestamp()
Returns the 60-bit timestamp value of the UUID in a long.
This field only exists in a time-based (version 1) UUID.
toString
public String toString()
Returns a String representation of the UUID.
The format of the standard string representation (given in RFC4122) is:
time-low "-" time-mid "-"
time-high-and-version "-"
clock-seq-and-reserved
clock-seq-low "-" node
Where each field is represented as a hex string.
- toString in interface Object
- the String representation.
variant
public int variant()
Returns the variant of the UUID
This may be:
0 = Reserved for NCS backwards-compatibility
2 = Leach-Salz (supports the other methods in this class)
6 = Reserved for Microsoft backwards-compatibility
7 = (reserved for future use)
version
public int version()
Returns the version # of the UUID.
Valid version numbers for a variant 2 UUID are:
1 = Time based UUID
2 = DCE security UUID
3 = Name-based UUID using MD5 hashing
4 = Randomly generated UUID
5 = Name-based UUID using SHA-1 hashing
UUID.java -- Class that represents a UUID object.
Copyright (C) 2006 Free Software Foundation, Inc.
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