net.i2p.router

Class RouterClock

java.lang.Object

net.i2p.util.Clock

net.i2p.router.RouterClock

All Implemented Interfaces:

Timestamper.UpdateListener

public class RouterClock
extends Clock

Alternate location for determining the time which takes into account an offset. This offset will ideally be periodically updated so as to serve as the difference between the local computer's current time and the time as known by some reference (such as an NTP synchronized clock). RouterClock is a subclass of Clock with access to router transports. Configuration permitting, it will block clock offset changes which would increase peer clock skew.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	RouterClock.ClockShiftListener Listener interface for receiving notifications when the router clock shifts.

Nested classes/interfaces inherited from class net.i2p.util.Clock

Clock.ClockUpdateListener

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_STRATUM

Fields inherited from class net.i2p.util.Clock

_alreadyChanged, _context, _isSystemClockBad, _offset, _startedOn, _statCreated, MAX_LIVE_OFFSET, MAX_OFFSET, MIN_OFFSET_CHANGE

Constructor Summary

Constructors

Constructor and Description
RouterClock(RouterContext context) Does not start.

Method Summary

Modifier and Type	Method and Description
void	addShiftListener(RouterClock.ClockShiftListener lsnr) Add a listener to be notified of massive system clock shifts.
long	getDeltaOffset() Deprecated.
Timestamper	getTimestamper() Get the timestamper used for time synchronization.
long	now() Retrieve the current time synchronized with whatever reference clock is in use.
void	removeShiftListener(RouterClock.ClockShiftListener lsnr) Remove a clock shift listener.
void	setNow(long realTime, int stratum) Set the current time, used by the timestamper when synchronizing.
void	setOffset(long offsetMs, boolean force) Specify how far away from the "correct" time the computer is - a positive value means that the system time is slow, while a negative value means the system time is fast.
void	start() Start the router clock and its associated timestamper.

Methods inherited from class net.i2p.util.Clock

addUpdateListener, fireOffsetChanged, getInstance, getLog, getOffset, getUpdatedSuccessfully, removeUpdateListener, setNow, setOffset

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_STRATUM

public static final int DEFAULT_STRATUM

See Also:

Constant Field Values

Constructor Detail

RouterClock

public RouterClock(RouterContext context)

Does not start. Caller MUST call start()

Method Detail

addShiftListener

public void addShiftListener(RouterClock.ClockShiftListener lsnr)

Add a listener to be notified of massive system clock shifts. These are shifts of one minute or more.

Parameters:

lsnr - the listener to add

getDeltaOffset

@Deprecated
public long getDeltaOffset()

Deprecated.

getTimestamper

public Timestamper getTimestamper()

Get the timestamper used for time synchronization.

Overrides:

getTimestamper in class Clock

Returns:

the RouterTimestamper instance

now

public long now()

Retrieve the current time synchronized with whatever reference clock is in use. Do really simple clock slewing, like NTP but without jitter prevention. Slew the clock toward the desired offset, but only up to a maximum slew rate, and never let the clock go backwards because of slewing. Take care to only access the volatile variables once for speed and to avoid having another thread change them This is called about a zillion times a second, so we can do the slewing right here rather than in some separate thread to keep it simple. Avoiding backwards clocks when updating in a thread would be hard too.

Overrides:

now in class Clock

removeShiftListener

public void removeShiftListener(RouterClock.ClockShiftListener lsnr)

Remove a clock shift listener.

Parameters:

lsnr - the listener to remove

setNow

public void setNow(long realTime,
                   int stratum)

Set the current time, used by the timestamper when synchronizing.

Specified by:

setNow in interface Timestamper.UpdateListener

Overrides:

setNow in class Clock

Parameters:

realTime - the current time from the time source

stratum - the stratum level of the time source (lower is better)

setOffset

public void setOffset(long offsetMs,
                      boolean force)

Specify how far away from the "correct" time the computer is - a positive value means that the system time is slow, while a negative value means the system time is fast.

Overrides:

setOffset in class Clock

Parameters:

offsetMs - the delta from System.currentTimeMillis() (NOT the delta from now())

start

public void start()

Start the router clock and its associated timestamper. The timestamper will begin synchronizing with NTP or peer time sources.