org.apache.commons.id.uuid.clock
Class ThreadClockImpl

java.lang.Object
  java.lang.Thread
      org.apache.commons.id.uuid.clock.ThreadClockImpl

All Implemented Interfaces:

java.lang.Runnable, Clock

public final class ThreadClockImpl
extends java.lang.Thread
implements Clock

Clock provides a timing mechanism for returning the current time in 100-nano second intervals since 00:00:00.00, 15 October 1582.

This Class consumes a single thread which will die off if not utilized before the expiration. Subsequent calls after a thread expires start a new thread. Compensates for jvm time resolution issues. This clock should be used in instances where the system resolution does not perform adequately - the clocking resolution on some windows virtual machines can range from 10 to 50 milliseconds before the System.currentTimeMillis changes. In instances where 10,000 or more uuid's may be generated in a millisecond this Clock implementation may be required.

Version:

$Revision: 480488 $ $Date: 2006-11-29 08:57:26 +0000 (Wed, 29 Nov 2006) $

Author:

Commons-Id Team

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

static long

DEFAULT_THREAD_LIFE Default time to live of the Clock thread in milliseconds

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Fields inherited from interface org.apache.commons.id.uuid.clock.Clock

DEFAULT_CLOCK_IMPL, GREGORIAN_CHANGE_OFFSET, INTERVALS_PER_MILLI

Constructor Summary

ThreadClockImpl()
Public constructor to instantiate a Clock instance.

Method Summary

static long	getThreadLife() Returns the thread life in milliseconds.
long	getUUIDTime() Method returns the clocks current time in 100-nanosecond intervals since the Gregorian calander change.
void	run() Threads run method that increments the clock and resets the generated nano seconds counter.
static void	setThreadLife(long threadLifeLen)

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_THREAD_LIFE

public static final long DEFAULT_THREAD_LIFE

Default time to live of the Clock thread in milliseconds

See Also:

Constant Field Values

Constructor Detail

ThreadClockImpl

public ThreadClockImpl()

Public constructor to instantiate a Clock instance.

Method Detail

getThreadLife

public static long getThreadLife()

Returns the thread life in milliseconds. If the clock thread is not accessed within this time span the thread will die off.

Returns:

thread life time span in milliseconds

setThreadLife

public static void setThreadLife(long threadLifeLen)

Parameters:

threadLifeLen - milliseconds this thread should live for. Each call to getCurrentTime resets the expiration time value.

run

public void run()

Threads run method that increments the clock and resets the generated nano seconds counter.

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread

getUUIDTime

public long getUUIDTime()
                 throws OverClockedException

Method returns the clocks current time in 100-nanosecond intervals since the Gregorian calander change. Calendar.GREGORIAN_OFFSET

Specified by:

getUUIDTime in interface Clock

Returns:

Coordinated Universal Time (UTC) as a count of 100- nanosecond intervals since 00:00:00.00, 15 October 1582.

Throws:

OverClockedException - an exception when the number of timestamps generated exceeds the allowable timestamps for the system time interval.