Package org.glassfish.jersey.server.internal.monitoring.core

Class AbstractSlidingWindowTimeReservoir<V>

java.lang.Object

org.glassfish.jersey.server.internal.monitoring.core.AbstractSlidingWindowTimeReservoir<V>

Type Parameters:

V - The type of values to store in this sliding window reservoir

All Implemented Interfaces:

TimeReservoir<V>

Direct Known Subclasses:

AggregatedSlidingWindowTimeReservoir, SlidingWindowTimeReservoir

public abstract class AbstractSlidingWindowTimeReservoir<V>
extends java.lang.Object
implements TimeReservoir<V>

An abstract TimeReservoir implementation backed by a sliding window that stores only the measurements made in the last N seconds (or other startTime unit) and allows an update with data that happened in past (which is what makes it different from Dropwizard's Metrics SlidingTimeWindowReservoir.

The snapshot this reservoir returns has limitations as mentioned in TimeReservoir.

This reservoir is capable to store up to 2^ReservoirConstants.COLLISION_BUFFER_POWER, that is 256, in a granularity of nanoseconds. In other words, up to 256 values that occurred at the same nanosecond can be stored in this reservoir. For particular nanosecond, if the collision buffer exceeds, newly added values are thrown away.

See Also:

Dropwizard's
 Metrics SlidingTimeWindowReservoir

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	AbstractSlidingWindowTimeReservoir.DefaultSlidingWindowTrimmerHolder	The holder of the lazy loaded instance of the default trimmer.

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.concurrent.atomic.AtomicLong	greatestTick
private long	interval
private java.util.concurrent.TimeUnit	intervalUnit
private java.util.concurrent.ConcurrentNavigableMap<java.lang.Long,V>	measurements
private java.util.concurrent.atomic.AtomicLong	startTick
private SlidingWindowTrimmer<V>	trimmer
private java.util.concurrent.atomic.AtomicInteger	trimOff
private java.util.concurrent.atomic.AtomicLong	updateCount
private long	window

Constructor Summary

Constructors

Constructor	Description
AbstractSlidingWindowTimeReservoir(long window, java.util.concurrent.TimeUnit windowUnit, long startTime, java.util.concurrent.TimeUnit startTimeUnit)	Creates a new SlidingWindowTimeReservoir with the start time and window of startTime.
AbstractSlidingWindowTimeReservoir(long window, java.util.concurrent.TimeUnit windowUnit, long startTime, java.util.concurrent.TimeUnit startTimeUnit, SlidingWindowTrimmer<V> trimmer)	Creates a new base sliding time window reservoir with the start time and a specified time window.

Method Summary

Modifier and Type	Method	Description
private long	conditionallyUpdateGreatestTick(long tick)
private void	conditionallyUpdateStartTick(java.util.Map.Entry<java.lang.Long,V> firstEntry)	Updates the startTick in case that the sliding window was created AFTER the time of a value that updated this window.
UniformTimeSnapshot	getSnapshot(long time, java.util.concurrent.TimeUnit timeUnit)	Returns a snapshot of the reservoir's values at given time or newer.
long	interval(java.util.concurrent.TimeUnit timeUnit)	The time interval this reservoir stores data of.
private long	roundTick(long tick)	The purpose of this method is to deal with the fact that data for the same nanosecond can be distributed in an interval [0,256).
int	size(long time, java.util.concurrent.TimeUnit timeUnit)	Returns the number of values recorded at given time or newer.
protected abstract UniformTimeSnapshot	snapshot(java.util.Collection<V> values, long timeInterval, java.util.concurrent.TimeUnit timeIntervalUnit, long time, java.util.concurrent.TimeUnit timeUnit)	Subclasses are required to instantiate UniformTimeSnapshot on their own.
private long	tick(long time, java.util.concurrent.TimeUnit timeUnit)
private void	trim()
private void	trim(long baselineTick)
private boolean	trimEnabled()
void	update(V value, long time, java.util.concurrent.TimeUnit timeUnit)	Adds a new recorded value to the reservoir bound to a given time.

Methods inherited from class java.lang.Object

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

Field Detail

measurements

private final java.util.concurrent.ConcurrentNavigableMap<java.lang.Long,V> measurements

window

private final long window

greatestTick

private final java.util.concurrent.atomic.AtomicLong greatestTick

updateCount

private final java.util.concurrent.atomic.AtomicLong updateCount

startTick

private final java.util.concurrent.atomic.AtomicLong startTick

trimOff

private final java.util.concurrent.atomic.AtomicInteger trimOff

trimmer

private final SlidingWindowTrimmer<V> trimmer

interval

private final long interval

intervalUnit

private final java.util.concurrent.TimeUnit intervalUnit

Constructor Detail

AbstractSlidingWindowTimeReservoir

public AbstractSlidingWindowTimeReservoir(long window,
                                          java.util.concurrent.TimeUnit windowUnit,
                                          long startTime,
                                          java.util.concurrent.TimeUnit startTimeUnit)

Creates a new SlidingWindowTimeReservoir with the start time and window of startTime.

Parameters:

window - The window of startTime

windowUnit - The unit of window

startTime - The start time from which this reservoir calculates measurements

startTimeUnit - The start time unit

AbstractSlidingWindowTimeReservoir

public AbstractSlidingWindowTimeReservoir(long window,
                                          java.util.concurrent.TimeUnit windowUnit,
                                          long startTime,
                                          java.util.concurrent.TimeUnit startTimeUnit,
                                          SlidingWindowTrimmer<V> trimmer)

Creates a new base sliding time window reservoir with the start time and a specified time window.

Parameters:

window - The window of startTime.

windowUnit - The unit of window.

startTime - The start time from which this reservoir calculates measurements.

startTimeUnit - The start time unit.

trimmer - The trimmer to use for trimming, if null, default trimmer is used.

Method Detail

size

public int size(long time,
                java.util.concurrent.TimeUnit timeUnit)

Description copied from interface: TimeReservoir

Returns the number of values recorded at given time or newer. It may not be supported to return a size in past due to performance optimizations.

Specified by:

size in interface TimeReservoir<V>

Parameters:

time - The time to get the size for

timeUnit - Time unit of the provided time

Returns:

the number of values recorded for given time or newer

update

public void update(V value,
                   long time,
                   java.util.concurrent.TimeUnit timeUnit)

Description copied from interface: TimeReservoir

Adds a new recorded value to the reservoir bound to a given time.

Specified by:

update in interface TimeReservoir<V>

Parameters:

value - a new recorded value

time - The time the recorded value occurred at

timeUnit - Time unit of the provided time

interval

public long interval(java.util.concurrent.TimeUnit timeUnit)

Description copied from interface: TimeReservoir

The time interval this reservoir stores data of.

Specified by:

interval in interface TimeReservoir<V>

Parameters:

timeUnit - The time unit in which to get the interval

Returns:

The time interval of this time reservoir

conditionallyUpdateGreatestTick

private long conditionallyUpdateGreatestTick(long tick)

conditionallyUpdateStartTick

private void conditionallyUpdateStartTick(java.util.Map.Entry<java.lang.Long,V> firstEntry)

Updates the startTick in case that the sliding window was created AFTER the time of a value that updated this window.

Parameters:

firstEntry - The first entry of the windowed measurments

snapshot

protected abstract UniformTimeSnapshot snapshot(java.util.Collection<V> values,
                                                long timeInterval,
                                                java.util.concurrent.TimeUnit timeIntervalUnit,
                                                long time,
                                                java.util.concurrent.TimeUnit timeUnit)

Subclasses are required to instantiate UniformTimeSnapshot on their own.

Parameters:

values - The values to create the snapshot from

timeInterval - The time interval this snapshot conforms to

timeIntervalUnit - The interval unit of the time interval

time - The time of the request of the snapshot

timeUnit - The unit of the time of the snapshot request

Returns:

The snapshot

getSnapshot

public UniformTimeSnapshot getSnapshot(long time,
                                       java.util.concurrent.TimeUnit timeUnit)

Description copied from interface: TimeReservoir

Returns a snapshot of the reservoir's values at given time or newer. It may not be supported to return a snapshot in past due to performance optimizations.

Specified by:

getSnapshot in interface TimeReservoir<V>

Parameters:

time - The time for which to get the snapshot

timeUnit - Time unit of the provided time

Returns:

a snapshot of the reservoir's values for given time or newer

tick

private long tick(long time,
                  java.util.concurrent.TimeUnit timeUnit)

trim

private void trim()

trim

private void trim(long baselineTick)

trimEnabled

private boolean trimEnabled()

roundTick

private long roundTick(long tick)

The purpose of this method is to deal with the fact that data for the same nanosecond can be distributed in an interval [0,256). By rounding the tick, we get the tick to which all the other ticks from the same interval belong.

Parameters:

tick - The tick

Returns:

The rounded tick