public class UUID
extends java.lang.Object
implements java.io.Serializable, java.lang.Comparable
构造器和说明 |
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UUID(long mostSigBits,
long leastSigBits)
Constructs a new UUID using the specified data.
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限定符和类型 | 方法和说明 |
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int |
clockSequence()
The clock sequence value associated with this UUID.
|
int |
compareTo(java.lang.Object val)
Compares this UUID with the specified UUID.
|
boolean |
equals(java.lang.Object obj)
Compares this object to the specified object.
|
static UUID |
fromString(java.lang.String name)
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(byte[] name)
Static factory to retrieve a type 3 (name based) UUID based on
the specified byte array.
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long |
node()
The node value associated with this UUID.
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static UUID |
randomUUID()
Static factory to retrieve a type 4 (pseudo randomly generated) UUID.
|
long |
timestamp()
The timestamp value associated with this UUID.
|
java.lang.String |
toString()
Returns a
String object representing this
UUID . |
int |
variant()
The variant number associated with this UUID.
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int |
version()
The version number associated with this UUID.
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public UUID(long mostSigBits, long leastSigBits)
mostSigBits
- leastSigBits
- public static UUID randomUUID()
UUID
is generated using a cryptographically
strong pseudo random number generator.public static UUID nameUUIDFromBytes(byte[] name)
name
- a byte array to be used to construct a UUID.public static UUID fromString(java.lang.String name)
toString()
method.name
- a string that specifies a UUID.java.lang.IllegalArgumentException
- if name does not conform to the string representation as
described in toString()
.public long getLeastSignificantBits()
public long getMostSignificantBits()
public int version()
public int variant()
public long timestamp()
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.
java.lang.UnsupportedOperationException
- if this UUID is not a version 1 UUID.public int clockSequence()
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.
java.lang.UnsupportedOperationException
- if this UUID is not a version 1 UUID.public long node()
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.
java.lang.UnsupportedOperationException
- if this UUID is not a version 1 UUID.public java.lang.String toString()
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"
toString
在类中 java.lang.Object
public int hashCode()
UUID
.hashCode
在类中 java.lang.Object
public boolean equals(java.lang.Object obj)
equals
在类中 java.lang.Object
obj
- the object to compare with.true
if the objects are the same;
false
otherwise.public int compareTo(java.lang.Object val)
The first of two UUIDs follows the second if the most significant field in which the UUIDs differ is greater for the first UUID.
compareTo
在接口中 java.lang.Comparable
val
- UUID to which this UUID is to be
compared.