com.eaio.uuid

Class UUID

java.lang.Object

com.eaio.uuid.UUID

All Implemented Interfaces:

Externalizable, Serializable, Cloneable, Comparable<UUID>, IDLEntity

public class UUID
extends Object
implements Comparable<UUID>, Externalizable, Cloneable, IDLEntity

Creates UUIDs according to the DCE Universal Token Identifier specification.

All you need to know:

 UUID u = new UUID();
 

Version:

$Id: UUID.java 4688 2012-03-09 14:49:49Z johann $

Author:

Johann Burkard

See Also:

http://www.opengroup.org/onlinepubs/9629399/apdxa.htm , http://www.uddi.org/pubs/draft-leach-uuids-guids-01.txt , UUID, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
long	clockSeqAndNode The clock sequence and node field of the UUID.
long	time The time field of the UUID.

Constructor Summary

Constructors

Constructor and Description
UUID() Constructor for UUID.
UUID(CharSequence s) Parses a textual representation of a UUID.
UUID(long time, long clockSeqAndNode) Constructor for UUID.
UUID(UUID u) Copy constructor for UUID.

Method Summary

Methods

Modifier and Type	Method and Description
Object	clone() Clones this UUID.
int	compareTo(UUID t) Compares this UUID to another Object.
boolean	equals(Object obj) Compares two Objects for equality.
long	getClockSeqAndNode() Returns the clock and node field of the UUID (lower 64 bits).
long	getTime() Returns the time field of the UUID (upper 64 bits).
int	hashCode() Returns a hash code of this UUID.
static UUID	nilUUID() Returns the nil UUID (a UUID whose values are both set to zero).
void	readExternal(ObjectInput in) Tweaked Serialization routine.
Appendable	toAppendable(Appendable a) Appends a String representation of this object to the given Appendable object.
String	toString() Returns this UUID as a String.
StringBuffer	toStringBuffer(StringBuffer in) Appends a String representation of this to the given StringBuffer or creates a new one if none is given.
void	writeExternal(ObjectOutput out) Tweaked Serialization routine.

Methods inherited from class java.lang.Object

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

Field Detail

time

public long time

The time field of the UUID.

clockSeqAndNode

public long clockSeqAndNode

The clock sequence and node field of the UUID.

Constructor Detail

UUID

public UUID()

Constructor for UUID. Constructs a new, unique UUID.

See Also:

UUIDGen.newTime(), UUIDGen.getClockSeqAndNode()

UUID

public UUID(long time,
    long clockSeqAndNode)

Constructor for UUID. Constructs a UUID from two long values.

Parameters:

time - the upper 64 bits

clockSeqAndNode - the lower 64 bits

UUID

public UUID(UUID u)

Copy constructor for UUID. Values of the given UUID are copied.

Parameters:

u - the UUID, may not be null

UUID

public UUID(CharSequence s)

Parses a textual representation of a UUID.

No validation is performed. If the CharSequence is shorter than 36 characters, ArrayIndexOutOfBoundsExceptions will be thrown.

Parameters:

s - the CharSequence, may not be null

Method Detail

compareTo

public int compareTo(UUID t)

Compares this UUID to another Object. Throws a ClassCastException if the other Object is not an instance of the UUID class. Returns a value smaller than zero if the other UUID is "larger" than this UUID and a value larger than zero if the other UUID is "smaller" than this UUID.

Specified by:

compareTo in interface Comparable<UUID>

Parameters:

t - the other UUID, may not be null

Returns:

a value < 0, 0 or a value > 0

Throws:

ClassCastException

See Also:

Comparable.compareTo(java.lang.Object)

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Tweaked Serialization routine.

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException

Tweaked Serialization routine.

Specified by:

readExternal in interface Externalizable

Throws:

IOException

toString

public final String toString()

Returns this UUID as a String.

Overrides:

toString in class Object

Returns:

a String, never null

See Also:

Object.toString(), toAppendable(Appendable)

toStringBuffer

public StringBuffer toStringBuffer(StringBuffer in)

Appends a String representation of this to the given StringBuffer or creates a new one if none is given.

Parameters:

in - the StringBuffer to append to, may be null

Returns:

a StringBuffer, never null

See Also:

toAppendable(Appendable)

toAppendable

public Appendable toAppendable(Appendable a)

Appends a String representation of this object to the given Appendable object.

For reasons I'll probably never understand, Sun has decided to have a number of I/O classes implement Appendable which forced them to destroy an otherwise nice and simple interface with IOExceptions.

I decided to ignore any possible IOExceptions in this method.

Parameters:

a - the Appendable object, may be null

Returns:

an Appendable object, defaults to a StringBuilder if a is null

hashCode

public int hashCode()

Returns a hash code of this UUID. The hash code is calculated by XOR'ing the upper 32 bits of the time and clockSeqAndNode fields and the lower 32 bits of the time and clockSeqAndNode fields.

Overrides:

hashCode in class Object

Returns:

an int representing the hash code

See Also:

Object.hashCode()

clone

public Object clone()

Clones this UUID.

Overrides:

clone in class Object

Returns:

a new UUID with identical values, never null

getTime

public final long getTime()

Returns the time field of the UUID (upper 64 bits).

Returns:

the time field

getClockSeqAndNode

public final long getClockSeqAndNode()

Returns the clock and node field of the UUID (lower 64 bits).

Returns:

the clockSeqAndNode field

equals

public boolean equals(Object obj)

Compares two Objects for equality.

Overrides:

equals in class Object

Parameters:

obj - the Object to compare this UUID with, may be null

Returns:

true if the other Object is equal to this UUID, false if not

See Also:

Object.equals(Object)

nilUUID

public static UUID nilUUID()

Returns the nil UUID (a UUID whose values are both set to zero).

Starting with version 2.0, this method does return a new UUID instance every time it is called. Earlier versions returned one instance. This has now been changed because this UUID has public, non-final instance fields. Returning a new instance is therefore more safe.

Returns:

a nil UUID, never null