java.lang.Object
- com.github.f4b6a3.uuid.alt.GUID

All Implemented Interfaces:

Serializable, Comparable<GUID>
```
public final class GUID
extends Object
implements Serializable, Comparable<GUID>
```
A class that represents and generates GUIDs/UUIDs.
It serves as an alternative to the classic JDK's UUID.
It also serves as a self-contained generator, independent of the rest of the library. This can result in fewer classes being loaded.
This generator was designed to be an alternative to UuidCreator with three primary objectives in mind: clean interface, simple implementation, and high performance. It was inspired by popular libraries for Javascript and Python.
The name GUID was chosen to avoid confusion with the classic JDK's UUID class. This naming choice was made so that when you see the word GUID in the source code, you can be sure it's not the JDK's built-in UUID.
Instances of this class are immutable and static methods of this class are thread safe.

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`GUID_BYTES`	Number of bytes of a GUID.
`static int`	`GUID_CHARS`	Number of characters of a GUID.
`static byte`	`LOCAL_DOMAIN_GROUP`	The group domain, interpreted as POSIX GID domain on POSIX systems.
`static byte`	`LOCAL_DOMAIN_ORG`	The organization domain, site-defined.
`static byte`	`LOCAL_DOMAIN_PERSON`	The principal domain, interpreted as POSIX UID domain on POSIX systems.
`static GUID`	`MAX`	A special GUID that has all 128 bits set to ONE.
`static GUID`	`NAMESPACE_DNS`	Name space to be used when the name string is a fully-qualified domain name.
`static GUID`	`NAMESPACE_OID`	Name space to be used when the name string is an ISO OID.
`static GUID`	`NAMESPACE_URL`	Name space to be used when the name string is a URL.
`static GUID`	`NAMESPACE_X500`	Name space to be used when the name string is an X.500 DN (DER or text).
`static GUID`	`NIL`	A special GUID that has all 128 bits set to ZERO.

Constructor Summary

Constructors
Constructor	Description
`GUID(byte[] bytes)`	Creates a new GUID.
`GUID(long mostSignificantBits, long leastSignificantBits)`	Creates a new GUID.
`GUID(GUID guid)`	Creates a new GUID.
`GUID(String string)`	Creates a new GUID.
`GUID(UUID uuid)`	Creates a new GUID.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`compareTo(GUID other)`	Compares two GUIDs as unsigned 128-bit integers.
`boolean`	`equals(Object other)`	Checks if some other GUID is equal to this one.
`int`	`hashCode()`	Returns a hash code value for the GUID.
`byte[]`	`toBytes()`	Converts the GUID into a byte array.
`String`	`toString()`	Converts the GUID into a canonical string.
`UUID`	`toUUID()`	Converts the GUID into a JDK's UUID.
`static GUID`	`v1()`	Returns a gregorian time-based unique identifier (UUIDv1).
`static GUID`	`v2(byte localDomain, int localIdentifier)`	Returns a DCE Security unique identifier (UUIDv2).
`static GUID`	`v3(GUID namespace, String name)`	Returns a name-based unique identifier that uses MD5 hashing (UUIDv3).
`static GUID`	`v4()`	Returns a random-based unique identifier (UUIDv4).
`static GUID`	`v5(GUID namespace, String name)`	Returns a name-based unique identifier that uses SHA-1 hashing (UUIDv5).
`static GUID`	`v6()`	Returns a reordered gregorian time-based unique identifier (UUIDv6).
`static GUID`	`v7()`	Returns a Unix epoch time-based unique identifier (UUIDv7).
`static GUID`	`v8(GUID namespace, String name)`	Returns a name-based unique identifier that uses SHA-256 hashing (UUIDv8).
`static boolean`	`valid(String string)`	Checks if the GUID string is valid.
`int`	`version()`	Returns the version number of this GUID.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - NIL
```
public static final GUID NIL
```
    A special GUID that has all 128 bits set to ZERO.
  - MAX
```
public static final GUID MAX
```
    A special GUID that has all 128 bits set to ONE.
  - NAMESPACE_DNS
```
public static final GUID NAMESPACE_DNS
```
    Name space to be used when the name string is a fully-qualified domain name.
  - NAMESPACE_URL
```
public static final GUID NAMESPACE_URL
```
    Name space to be used when the name string is a URL.
  - NAMESPACE_OID
```
public static final GUID NAMESPACE_OID
```
    Name space to be used when the name string is an ISO OID.
  - NAMESPACE_X500
```
public static final GUID NAMESPACE_X500
```
    Name space to be used when the name string is an X.500 DN (DER or text).
  - LOCAL_DOMAIN_PERSON
```
public static final byte LOCAL_DOMAIN_PERSON
```
    The principal domain, interpreted as POSIX UID domain on POSIX systems.
    
    See Also:
    
    Constant Field Values
  - LOCAL_DOMAIN_GROUP
```
public static final byte LOCAL_DOMAIN_GROUP
```
    The group domain, interpreted as POSIX GID domain on POSIX systems.
    
    See Also:
    
    Constant Field Values
  - LOCAL_DOMAIN_ORG
```
public static final byte LOCAL_DOMAIN_ORG
```
    The organization domain, site-defined.
    
    See Also:
    
    Constant Field Values
  - GUID_CHARS
```
public static final int GUID_CHARS
```
    Number of characters of a GUID.
    
    See Also:
    
    Constant Field Values
  - GUID_BYTES
```
public static final int GUID_BYTES
```
    Number of bytes of a GUID.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - GUID
```
public GUID(GUID guid)
```
    Creates a new GUID.
    Useful to make copies of GUIDs.
    
    Parameters:
    
    guid - a GUID
    
    Throws:
    
    IllegalArgumentException - if the input is null
  - GUID
```
public GUID(UUID uuid)
```
    Creates a new GUID.
    Useful to make copies of JDK's UUIDs.
    
    Parameters:
    
    uuid - a JDK's UUID
    
    Throws:
    
    IllegalArgumentException - if the input is null
  - GUID
```
public GUID(long mostSignificantBits,
            long leastSignificantBits)
```
    Creates a new GUID.
    
    Parameters:
    
    mostSignificantBits - the first 8 bytes as a long value
    
    leastSignificantBits - the last 8 bytes as a long value
  - GUID
```
public GUID(byte[] bytes)
```
    Creates a new GUID.
    
    Parameters:
    
    bytes - an array of 16 bytes
    
    Throws:
    
    IllegalArgumentException - if bytes are null or its length is not 16
  - GUID
```
public GUID(String string)
```
    Creates a new GUID.
    
    Parameters:
    
    string - a canonical string
    
    Throws:
    
    IllegalArgumentException - if the input string is invalid
- Method Detail
  - v1
```
public static GUID v1()
```
    Returns a gregorian time-based unique identifier (UUIDv1).
    The clock sequence and node bits are reset to a pseudo-random value for each new UUIDv1 generated.
    Usage:
    GUID guid = GUID.v1();
    Returns:
    
    a GUID
  - v2
```
public static GUID v2(byte localDomain,
                      int localIdentifier)
```
    Returns a DCE Security unique identifier (UUIDv2).
    Usage:
    GUID guid = GUID.v2(Uuid.LOCAL_DOMAIN_PERSON, 1234567890);
    Parameters:
    
    localDomain - a custom local domain byte
    
    localIdentifier - a local identifier
    
    Returns:
    
    a GUID
  - v3
```
public static GUID v3(GUID namespace,
                      String name)
```
    Returns a name-based unique identifier that uses MD5 hashing (UUIDv3).
    Usage:
    GUID guid = GUID.v3(Uuid.NAMESPACE_DNS, "www.example.com");
    Parameters:
    
    namespace - a GUID
    
    name - a string
    
    Returns:
    
    a GUID
  - v4
```
public static GUID v4()
```
    Returns a random-based unique identifier (UUIDv4).
    It is an extremely fast and non-blocking alternative to UUID.randomUUID().
    It employs ThreadLocalRandom which works very well, although not cryptographically strong.
    Usage:
    GUID guid = GUID.v4();
    Returns:
    
    a GUID
  - v5
```
public static GUID v5(GUID namespace,
                      String name)
```
    Returns a name-based unique identifier that uses SHA-1 hashing (UUIDv5).
    Usage:
    GUID guid = GUID.v5(Uuid.NAMESPACE_DNS, "www.example.com");
    Parameters:
    
    namespace - a GUID
    
    name - a string
    
    Returns:
    
    a GUID
  - v6
```
public static GUID v6()
```
    Returns a reordered gregorian time-based unique identifier (UUIDv6).
    The clock sequence and node bits are reset to a pseudo-random value for each new UUIDv6 generated.
    Usage:
    GUID guid = GUID.v6();
    Returns:
    
    a GUID
  - v7
```
public static GUID v7()
```
    Returns a Unix epoch time-based unique identifier (UUIDv7).
    Usage:
    GUID guid = GUID.v7();
    Returns:
    
    a GUID
  - v8
```
public static GUID v8(GUID namespace,
                      String name)
```
    Returns a name-based unique identifier that uses SHA-256 hashing (UUIDv8).
    Usage:
    GUID guid = GUID.v8(Uuid.NAMESPACE_DNS, "www.example.com");
    Parameters:
    
    namespace - a GUID
    
    name - a string
    
    Returns:
    
    a GUID
  - valid
```
public static boolean valid(String string)
```
    Checks if the GUID string is valid.
    
    Parameters:
    
    string - a GUID string
    
    Returns:
    
    true if valid, false if invalid
  - toBytes
```
public byte[] toBytes()
```
    Converts the GUID into a byte array.
    
    Returns:
    
    an byte array.
  - toString
```
public String toString()
```
    Converts the GUID into a canonical string.
    
    Overrides:
    
    toString in class Object
  - toUUID
```
public UUID toUUID()
```
    Converts the GUID into a JDK's UUID.
    It simply copies all 128 bits into a new JDK's UUID.
    You can think of the GUID class as a JDK's UUID wrapper. This method unwraps a JDK's UUID instance so that you can store it in the built-in format or access its classic interface.
    Usage:
    UUID uuid = GUID.v4().toUUID();
    Returns:
    
    a JDK's UUID.
  - version
```
public int version()
```
    Returns the version number of this GUID.
    
    Returns:
    
    a version number
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for the GUID.
    
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object other)
```
    Checks if some other GUID is equal to this one.
    
    Overrides:
    
    equals in class Object
  - compareTo
```
public int compareTo(GUID other)
```
    Compares two GUIDs as unsigned 128-bit integers.
    The first of two GUIDs is greater than the second if the most significant byte in which they differ is greater for the first GUID.
    If the second GUID is null, then it is treated as a NIL GUID, which has all its bits set to ZERO, instead of throwing a NullPointerException.
    This method differs from JDK's UUID.compareTo(UUID) as this method compares two GUIDs as unsigned 128-bit integers.
    It can be useful because JDK's UUID.compareTo(UUID) can lead to unexpected behavior due to its signed 64-bit comparison. Another reason is that JDK's UUID.compareTo(UUID) throws NullPointerException if it receives a null UUID.
    
    Specified by:
    
    compareTo in interface Comparable<GUID>
    
    Parameters:
    
    other - a second GUID to be compared with
    
    Returns:
    
    -1, 0 or 1 as this is less than, equal to, or greater than that

Class GUID

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NIL

MAX

NAMESPACE_DNS

NAMESPACE_URL

NAMESPACE_OID

NAMESPACE_X500

LOCAL_DOMAIN_PERSON

LOCAL_DOMAIN_GROUP

LOCAL_DOMAIN_ORG

GUID_CHARS

GUID_BYTES

Constructor Detail

GUID

GUID

GUID

GUID

GUID

Method Detail

v1

v2

v3

v4

v5

v6

v7

v8

valid

toBytes

toString

toUUID

version

hashCode

equals

compareTo