Class AnchoredClock

java.lang.Object

io.opentelemetry.sdk.trace.AnchoredClock

@Immutable
final class AnchoredClock
extends Object

A utility for returning wall times anchored to a given point in time. Wall time measurements will not be taken from the system, but instead are computed by adding monotonic time to the anchor point.

This is needed because Java has lower granularity for epoch times and tracing events are recorded more often. There is also a performance improvement in avoiding referencing the system's wall time where possible. Instead of computing a true wall time for every timestamp within a trace, we compute it once at the local root and then anchor all descendant span timestamps to this root's timestamp.

Field Summary

Fields

Modifier and Type	Field	Description
private final Clock	clock
private final long	epochNanos
private final long	nanoTime

Constructor Summary

Constructors

Modifier	Constructor	Description
private	AnchoredClock(Clock clock, long epochNanos, long nanoTime)

Method Summary

Modifier and Type	Method	Description
static AnchoredClock	create(Clock clock)	Returns a AnchoredClock.
(package private) long	now()	Returns the current epoch timestamp in nanos calculated using System.nanoTime() since the reference time read in the constructor.
(package private) long	startTime()	Returns the start time in nanos of this AnchoredClock.

Methods inherited from class Object

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

Field Details

clock

private final Clock clock

epochNanos

private final long epochNanos

nanoTime

private final long nanoTime

Constructor Details

AnchoredClock

private AnchoredClock(Clock clock,
 long epochNanos,
 long nanoTime)

Method Details

create

public static AnchoredClock create(Clock clock)

Returns a AnchoredClock.

Parameters:

clock - the Clock to be used to read the current epoch time and nanoTime.

Returns:

a MonotonicClock.

now

long now()

Returns the current epoch timestamp in nanos calculated using System.nanoTime() since the reference time read in the constructor. This time can be used for computing durations.

Returns:

the current epoch timestamp in nanos.

startTime

long startTime()

Returns the start time in nanos of this AnchoredClock.