Module io.prometheus.metrics.core

Package io.prometheus.metrics.core.metrics

Class SlidingWindow<T>

java.lang.Object

io.prometheus.metrics.core.metrics.SlidingWindow<T>

public class SlidingWindow<T>
extends Object

Maintains a ring buffer of T to implement a sliding time window.

This is used to maintain a sliding window of CKMSQuantiles for Summary metrics.

It is implemented in a generic way so that 3rd party libraries can use it for implementing sliding windows.

TODO: The current implementation is synchronized. There is likely room for optimization.

Constructor Summary

Constructors

Constructor	Description
SlidingWindow(Class<T> clazz, Supplier<T> constructor, ObjDoubleConsumer<T> observeFunction, long maxAgeSeconds, int ageBuckets)	Example: If the maxAgeSeconds is 60 and ageBuckets is 3, then 3 instances of T are maintained and the sliding window moves to the next instance of T every 20 seconds.

Method Summary

Modifier and Type	Method	Description
T	current()	Get the currently active instance of T.
void	observe(double value)	Observe a value.

Methods inherited from class java.lang.Object

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

Constructor Details

SlidingWindow

public SlidingWindow(Class<T> clazz,
 Supplier<T> constructor,
 ObjDoubleConsumer<T> observeFunction,
 long maxAgeSeconds,
 int ageBuckets)

Example: If the maxAgeSeconds is 60 and ageBuckets is 3, then 3 instances of T are maintained and the sliding window moves to the next instance of T every 20 seconds.

Parameters:

clazz - type of T

constructor - for creating a new instance of T as the old one gets evicted

observeFunction - for observing a value (e.g. calling t.observe(value)

maxAgeSeconds - after this amount of time an instance of T gets evicted.

ageBuckets - number of age buckets.

Method Details

current

public T current()

Get the currently active instance of T.

observe

public void observe(double value)

Observe a value.