BasicUUIDFactory (Apache Derby V10.14 Internals)

java.lang.Object
- org.apache.derby.impl.services.uuid.BasicUUIDFactory

All Implemented Interfaces:

UUIDFactory
```
public final class BasicUUIDFactory
extends java.lang.Object
implements UUIDFactory
```
A hack implementation of something similar to a DCE UUID generator. Generates unique 128-bit numbers based on the current machine's internet address, the current time, and a sequence number. This implementation should be made to conform to the DCE specification. ("DEC/HP, Network Computing Architecture, Remote Procedure Call Runtime Extensions Specification, version OSF TX1.0.11," Steven Miller, July 23, 1992. This is part of the OSF DCE Documentation. Chapter 10 describes the UUID generation algorithm.)
Some known deficiencies:
- Rather than using the 48-bit hardware network address, it uses the 32-bit IP address. IP addresses are not guaranteed to be unique.
- There is no provision for generating a suitably unique number if no IP address is available.
- Two processes running on this machine which start their respective UUID services within a millisecond of one another may generate duplicate UUIDS.
However, the intention is that UUIDs generated from this class will be unique with respect to UUIDs generated by other DCE UUID generators.

Field Summary

Fields
Modifier and Type	Field	Description
`private long`	`currentValue`
`private static long`	`INITIAL_VALUE`
`private long`	`majorId`
`private static long`	`MODULUS`
`private static long`	`MULTIPLIER`
`private static long`	`STEP`
`private long`	`timemillis`

Constructor Summary

Constructors
Constructor Description

BasicUUIDFactory()

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`private void`	`bumpMajor()`
`UUID`	`createUUID()`	Generate a new UUID.
`private static ModuleFactory`	`getMonitor()`	Privileged Monitor lookup.
`UUID`	`recreateUUID(java.lang.String uuidstring)`	Recreate a UUID previously generated UUID value.
`private void`	`resetCounters()`

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

- Field Detail
  - majorId
```
private long majorId
```
  - timemillis
```
private long timemillis
```
  - MODULUS
```
private static final long MODULUS
```
    See Also:
    
    Constant Field Values
  - MULTIPLIER
```
private static final long MULTIPLIER
```
    See Also:
    
    Constant Field Values
  - STEP
```
private static final long STEP
```
    See Also:
    
    Constant Field Values
  - INITIAL_VALUE
```
private static final long INITIAL_VALUE
```
    See Also:
    
    Constant Field Values
  - currentValue
```
private long currentValue
```
- Constructor Detail
  - BasicUUIDFactory
```
public BasicUUIDFactory()
```
- Method Detail
  - createUUID
```
public UUID createUUID()
```
    Generate a new UUID.
    
    Specified by:
    
    createUUID in interface UUIDFactory
    
    Returns:
    
    The UUID.
    
    See Also:
    
    UUIDFactory.createUUID()
  - recreateUUID
```
public UUID recreateUUID(java.lang.String uuidstring)
```
    Recreate a UUID previously generated UUID value.
    
    Specified by:
    
    recreateUUID in interface UUIDFactory
    
    Returns:
    
    The UUID.
    
    See Also:
    
    UUIDFactory.recreateUUID(java.lang.String)
  - bumpMajor
```
private void bumpMajor()
```
  - resetCounters
```
private void resetCounters()
```
  - getMonitor
```
private static ModuleFactory getMonitor()
```
    Privileged Monitor lookup. Must be private so that user code can't call this entry point.