Package io.prometheus.client.exemplars

Class DefaultExemplarSampler

java.lang.Object

io.prometheus.client.exemplars.DefaultExemplarSampler

All Implemented Interfaces:

CounterExemplarSampler, ExemplarSampler, HistogramExemplarSampler

public class DefaultExemplarSampler
extends Object
implements ExemplarSampler

Default Exemplar sampler.

Keeps each Exemplar for a minimum of ~7 seconds, then samples a new one.

Constructor Summary

Constructors

Constructor	Description
DefaultExemplarSampler(io.prometheus.client.exemplars.tracer.common.SpanContextSupplier spanContextSupplier)

Method Summary

Modifier and Type	Method	Description
Exemplar	sample(double value, double bucketFrom, double bucketTo, Exemplar previous)
Exemplar	sample(double increment, Exemplar previous)

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultExemplarSampler

public DefaultExemplarSampler(io.prometheus.client.exemplars.tracer.common.SpanContextSupplier spanContextSupplier)

Method Detail

sample

public Exemplar sample(double increment,
                       Exemplar previous)

Specified by:

sample in interface CounterExemplarSampler

Parameters:

increment - the value added to the counter on this event

previous - the previously sampled exemplar, or null if there is none.

Returns:

an Exemplar to be sampled, or null if the previous exemplar does not need to be updated. Returning null and returning previous is equivalent.

sample

public Exemplar sample(double value,
                       double bucketFrom,
                       double bucketTo,
                       Exemplar previous)

Specified by:

sample in interface HistogramExemplarSampler

Parameters:

value - the value to be observed.

bucketFrom - upper boundary of the previous bucket in the histogram. Will be Double.NEGATIVE_INFINITY if there is no previous bucket.

bucketTo - upper boundary of this histogram bucket. Will be Double.POSITIVE_INFINITY if this is the last bucket.

previous - the previously sampled exemplar, or null if there is none.

Returns:

an Exemplar to be sampled, or null if the previous exemplar does not need to be updated. Returning null and returning previous is equivalent.