co.codewizards.cloudstore.core

Class Uid

java.lang.Object

co.codewizards.cloudstore.core.Uid

All Implemented Interfaces:

Serializable, Comparable<Uid>

public class Uid
extends Object
implements Comparable<Uid>, Serializable

Universal identifier similar to a UUID.

The main difference is the encoding which is optimized for brevity. In contrast to the hex-encoding used by UUID, the toString() method uses standard base64url (RFC 4648). The difference to normal base64 is that base64url replaces '+' by '-' and '/' by '_' in order to make the encoded string usable in URLs without any escaping.

Important: The string-representation is case-sensitive!

Examples showing the difference of UUID vs. Uid:

 WQL8yMHUQ4FhZrB0cLux5g
 WCRAGMeiz-2PPaKdmn-iww
 Jd6_KRqpMivfuxXO4JmwtQ
 284tn0-92bIMRNV_4M53Tg
 8b726260-f9f3-439b-bf21-615bb4b6731d
 34fadc2b-5a58-4de8-b04c-6f315a6598cd
 15c3f6cb-6275-4557-b24c-2cd57cd07a6d
 11934d8c-d201-4a95-a714-e03ff48f5053
 46875d87-01ef-4ece-98cf-5a96a5946ef7

A string-encoded UUID always has a length 36 characters, while a Uid always has a length of 22 characters. In other words, the strings are 38.89% shorter.

Instances of this class are immutable.

Author:

Marco หงุ่ยตระกูล-Schulze - marco at codewizards dot co

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	LENGTH_BYTES Gets the length of an Uid in bytes.
static int	LENGTH_STRING Gets the length of an Uid in its String representation.

Constructor Summary

Constructors

Constructor and Description
Uid() Creates a new random Uid.
Uid(byte[] bytes)
Uid(long hi, long lo) Creates a new Uid with the given value.
Uid(String uidString) Creates a new Uid instance from the encoded value in uidString.

Method Summary

Modifier and Type	Method and Description
int	compareTo(Uid other)
boolean	equals(Object obj)
int	hashCode()
byte[]	toBytes()
String	toString() Gets a base64url-encoded string-representation of this Uid.

Methods inherited from class java.lang.Object

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

Field Detail

LENGTH_BYTES

public static final int LENGTH_BYTES

Gets the length of an Uid in bytes.

See Also:

Constant Field Values

LENGTH_STRING

public static final int LENGTH_STRING

Gets the length of an Uid in its String representation.

See Also:

Constant Field Values

Constructor Detail

Uid

public Uid()

Creates a new random Uid.

Uid

public Uid(long hi,
           long lo)

Creates a new Uid with the given value.

This constructor is equivalent to UUID(long, long).

Parameters:

hi - the most significant bits of the new Uid.

lo - the least significant bits of the new Uid.

Uid

public Uid(byte[] bytes)

Uid

public Uid(String uidString)

Creates a new Uid instance from the encoded value in uidString.

This constructor is symmetric to the toString() method: The output of toString() can be passed to this constructor to create a new instance with the same value as (and thus being equal to) the first instance.

Parameters:

uidString - the string-encoded value of the Uid.

See Also:

toString()

Method Detail

toBytes

public byte[] toBytes()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Gets a base64url-encoded string-representation of this Uid.

The string returned by this method can be passed to Uid(String) to create a new equal Uid instance.

Important: The string-representation is case-sensitive!

Inherited documentation:

Overrides:

toString in class Object

compareTo

public int compareTo(Uid other)

Specified by:

compareTo in interface Comparable<Uid>