io.github.resilience4j.core.metrics

Class FixedSizeSlidingWindowMetrics

java.lang.Object

io.github.resilience4j.core.metrics.FixedSizeSlidingWindowMetrics

All Implemented Interfaces:

Metrics

public class FixedSizeSlidingWindowMetrics
extends java.lang.Object
implements Metrics

A Metrics implementation is backed by a sliding window that aggregates only the last N calls.

The sliding window is implemented with a circular array of N measurements. If the time window size is 10, the circular array has always 10 measurements.

The sliding window incrementally updates a total aggregation. The total aggregation is updated incrementally when a new call outcome is recorded. When the oldest measurement is evicted, the measurement is subtracted from the total aggregation. (Subtract-on-Evict)

The time to retrieve a Snapshot is constant 0(1), since the Snapshot is pre-aggregated and is independent of the window size. The space requirement (memory consumption) of this implementation should be O(n).

Nested Class Summary

Nested classes/interfaces inherited from interface io.github.resilience4j.core.metrics.Metrics

Metrics.Outcome

Constructor Summary

Constructors

Constructor and Description
FixedSizeSlidingWindowMetrics(int windowSize) Creates a new FixedSizeSlidingWindowMetrics with the given window size.

Method Summary

Modifier and Type	Method and Description
Snapshot	getSnapshot() Returns a snapshot.
Snapshot	record(long duration, java.util.concurrent.TimeUnit durationUnit, Metrics.Outcome outcome) Records a call.

Methods inherited from class java.lang.Object

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

Constructor Detail

FixedSizeSlidingWindowMetrics

public FixedSizeSlidingWindowMetrics(int windowSize)

Creates a new FixedSizeSlidingWindowMetrics with the given window size.

Parameters:

windowSize - the window size

Method Detail

record

public Snapshot record(long duration,
                       java.util.concurrent.TimeUnit durationUnit,
                       Metrics.Outcome outcome)

Description copied from interface: Metrics

Records a call.

Specified by:

record in interface Metrics

Parameters:

duration - the duration of the call

durationUnit - the time unit of the duration

outcome - the outcome of the call

getSnapshot

public Snapshot getSnapshot()

Description copied from interface: Metrics

Returns a snapshot.

Specified by:

getSnapshot in interface Metrics

Returns:

a snapshot