org.apache.hadoop.hbase.util

Class MovingAverage<T>

java.lang.Object

org.apache.hadoop.hbase.util.MovingAverage<T>

Direct Known Subclasses:

SimpleMovingAverage, WindowMovingAverage

@InterfaceAudience.Private
public abstract class MovingAverage<T>
extends Object

The purpose of introduction of MovingAverage mainly is to measure execution time of a specific method, which can help us to know its performance fluctuation in response to different machine states or situations, better case, then to act accordingly.
In different situation, different MovingAverage algorithm can be used based on needs.

Field Summary

Fields

Modifier and Type	Field and Description
protected String	label
private static org.slf4j.Logger	LOG

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MovingAverage(String label)

Method Summary

Modifier and Type	Method and Description
abstract double	getAverageTime() Get average execution time of the measured method.
T	measure(TimeMeasurable<T> measurable) Measure elapsed time of a measurable method.
protected long	start() Mark start time of an execution.
protected long	stop(long startTime) Mark end time of an execution, and return its interval.
protected abstract void	updateMostRecentTime(long elapsed) Update the most recent data.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final org.slf4j.Logger LOG

label

protected final String label

Constructor Detail

MovingAverage

protected MovingAverage(String label)

Method Detail

start

protected long start()

Mark start time of an execution.

Returns:

time in ns.

stop

protected long stop(long startTime)

Mark end time of an execution, and return its interval.

Parameters:

startTime - start time of an execution

Returns:

elapsed time

measure

public T measure(TimeMeasurable<T> measurable)

Measure elapsed time of a measurable method.

Parameters:

measurable - method implements TimeMeasurable

Returns:

T it refers to the original return type of the measurable method

updateMostRecentTime

protected abstract void updateMostRecentTime(long elapsed)

Update the most recent data.

Parameters:

elapsed - elapsed time of the most recent measurement

getAverageTime

public abstract double getAverageTime()

Get average execution time of the measured method.

Returns:

average time in ns