Package io.opentelemetry.sdk.common
Interface Clock
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- All Known Implementing Classes:
SystemClock
@ThreadSafe public interface Clock
Interface for getting the current time.
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description static Clock
getDefault()
Returns a defaultClock
which reads from system time.long
nanoTime()
Returns a time measurement with nanosecond precision that can only be used to calculate elapsed time.long
now()
Returns the current epoch timestamp in nanos from this clock.default long
now(boolean highPrecision)
Returns the current epoch timestamp in nanos from this clock.
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Method Detail
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now
long now()
Returns the current epoch timestamp in nanos from this clock. This timestamp should only be used to compute a current time. To compute a duration, timestamps should always be obtained usingnanoTime()
. For example, this usage is correct.long startNanos = clock.nanoTime(); // Spend time... long durationNanos = clock.nanoTime() - startNanos;
This usage is NOT correct.
long startNanos = clock.now(); // Spend time... long durationNanos = clock.now() - startNanos;
Calling this is equivalent to calling
now(boolean)
withhighPrecision=true
.
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now
default long now(boolean highPrecision)
Returns the current epoch timestamp in nanos from this clock.This overload of
now()
includes ahighPrecision
argument which specifies whether the implementation should attempt to resolve higher precision at the potential expense of performance. For example, in java 9+ its sometimes possible to resolve ns precision higher than the ms precision ofSystem.currentTimeMillis()
, but doing so incurs a performance penalty which some callers may wish to avoid. In contrast, we don't currently know if resolving ns precision is possible in java 8, regardless of the value ofhighPrecision
.See
now()
javadoc for details on usage.- Since:
- 1.38.0
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nanoTime
long nanoTime()
Returns a time measurement with nanosecond precision that can only be used to calculate elapsed time.
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