com.almende.util.uuid.UUID Maven / Gradle / Ivy
/*
* UUID.java
*
* Created 07.02.2003
*
* eaio: UUID - an implementation of the UUID specification
* Copyright (c) 2003-2013 Johann Burkard ([email protected]) http://eaio.com.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
* NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package com.almende.util.uuid;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
/**
* Creates UUIDs according to the DCE Universal Token Identifier specification.
*
* All you need to know:
*
*
* UUID u = new UUID();
*
*
* @author Johann Burkard
* @version UUID.java 4688 2012-03-09 14:49:49Z johann $
* @see
* http://www.opengroup.org/onlinepubs/9629399/apdxa.htm
* @see
* http://www.uddi.org/pubs/draft-leach-uuids-guids-01.txt
* @see UUID
*/
public class UUID implements Comparable, Externalizable, Cloneable {
/**
* Hasn't ever changed between versions.
*/
static final long serialVersionUID = 7435962790062944603L;
/**
* The time field of the UUID.
*
* @serial
*/
private long time;
/**
* The clock sequence and node field of the UUID.
*
* @serial
*/
private long clockSeqAndNode;
/**
* Constructor for UUID. Constructs a new, unique UUID.
*
* @see UUIDGen#newTime()
* @see UUIDGen#getClockSeqAndNode()
*/
public UUID() {
this(UUIDGen.newTime(), UUIDGen.getClockSeqAndNode());
}
/**
* Constructor for UUID. Constructs a UUID from two long
* values.
*
* @param time
* the upper 64 bits
* @param clockSeqAndNode
* the lower 64 bits
*/
public UUID(final long time, final long clockSeqAndNode) {
this.time = time;
this.clockSeqAndNode = clockSeqAndNode;
}
/**
* Copy constructor for UUID. Values of the given UUID are copied.
*
* @param u
* the UUID, may not be null
*/
public UUID(final UUID u) {
this(u.time, u.clockSeqAndNode);
}
/**
* Parses a textual representation of a UUID.
*
* No validation is performed. If the {@link CharSequence} is shorter than
* 36 characters, {@link ArrayIndexOutOfBoundsException}s will be thrown.
*
* @param s
* the {@link CharSequence}, may not be null
*/
public UUID(final CharSequence s) {
this(Hex.parseLong(s.subSequence(0, 18)), Hex.parseLong(s.subSequence(
19, 36)));
}
/**
* Compares this UUID to another Object. Throws a {@link 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.
*
* @param t
* the other UUID, may not be null
* @return a value < 0, 0 or a value > 0
* @see java.lang.Comparable#compareTo(java.lang.Object)
*/
@Override
public int compareTo(final UUID t) {
if (this == t) {
return 0;
}
if (time > t.time) {
return 1;
}
if (time < t.time) {
return -1;
}
if (clockSeqAndNode > t.clockSeqAndNode) {
return 1;
}
if (clockSeqAndNode < t.clockSeqAndNode) {
return -1;
}
return 0;
}
/**
* Tweaked Serialization routine.
*
* @param out
* the out
* @throws IOException
* Signals that an I/O exception has occurred.
*/
@Override
public void writeExternal(final ObjectOutput out) throws IOException {
out.writeLong(time);
out.writeLong(clockSeqAndNode);
}
/**
* Tweaked Serialization routine.
*
* @param in
* the in
* @throws IOException
* Signals that an I/O exception has occurred.
*/
@Override
public void readExternal(final ObjectInput in) throws IOException {
time = in.readLong();
clockSeqAndNode = in.readLong();
}
/**
* Returns this UUID as a String.
*
* @return a String, never null
* @see java.lang.Object#toString()
* @see #toAppendable(Appendable)
*/
@Override
public final String toString() {
return toAppendable(null).toString();
}
/**
* Appends a String representation of this to the given {@link StringBuffer}
* or
* creates a new one if none is given.
*
* @param in
* the StringBuffer to append to, may be null
* @return a StringBuffer, never null
* @see #toAppendable(Appendable)
*/
public StringBuffer toStringBuffer(final StringBuffer in) {
StringBuffer out = in;
if (out == null) {
out = new StringBuffer(36);
} else {
out.ensureCapacity(out.length() + 36);
}
return (StringBuffer) toAppendable(out);
}
/**
* Appends a String representation of this object to the given.
*
* @param a
* the Appendable object, may be null
* @return an Appendable object, defaults to a {@link StringBuilder} if
* a is null {@link 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
* {@link IOException}s.
*
* I decided to ignore any possible IOExceptions in this method.
*/
public Appendable toAppendable(final Appendable a) {
Appendable out = a;
if (out == null) {
out = new StringBuilder(36);
}
try {
Hex.append(out, (int) (time >> 32)).append('-');
Hex.append(out, (short) (time >> 16)).append('-');
Hex.append(out, (short) time).append('-');
Hex.append(out, (short) (clockSeqAndNode >> 48)).append('-');
Hex.append(out, clockSeqAndNode, 12);
} catch (final IOException ex) {
// What were they thinking?
}
return out;
}
/**
* 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.
*
* @return an int representing the hash code
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return (int) ((time >> 32) ^ time ^ (clockSeqAndNode >> 32) ^ clockSeqAndNode);
}
/**
* Clones this UUID.
*
* @return a new UUID with identical values, never null
*/
@Override
public Object clone() {
try {
return super.clone();
} catch (final CloneNotSupportedException ex) {
// One of Sun's most epic fails.
return null;
}
}
/**
* Returns the time field of the UUID (upper 64 bits).
*
* @return the time field
*/
public final long getTime() {
return time;
}
/**
* Returns the clock and node field of the UUID (lower 64 bits).
*
* @return the clockSeqAndNode field
*/
public final long getClockSeqAndNode() {
return clockSeqAndNode;
}
/**
* Compares two Objects for equality.
*
* @param obj
* the Object to compare this UUID with, may be null
* @return true if the other Object is equal to this UUID,
* false if not
* @see java.lang.Object#equals(Object)
*/
@Override
public boolean equals(final Object obj) {
if (!(obj instanceof UUID)) {
return false;
}
return compareTo((UUID) obj) == 0;
}
/**
* 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.
*
* @return a nil UUID, never null
*/
public static UUID nilUUID() {
return new UUID(0, 0);
}
}