Package com.yahoo.concurrent.maintenance

Class Maintainer

java.lang.Object

com.yahoo.concurrent.maintenance.Maintainer

All Implemented Interfaces:

Runnable

public abstract class Maintainer
extends Object
implements Runnable

The base class for maintainers. A maintainer is some job which runs at a fixed rate to perform maintenance tasks.

Author:

bratseth, mpolden, jonmv

Field Summary

Fields

Modifier and Type	Field	Description
protected final Logger	log

Constructor Summary

Constructors

Constructor	Description
Maintainer(String name, Duration interval, Clock clock, JobControl jobControl, JobMetrics jobMetrics, List<String> clusterHostnames, boolean ignoreCollision)
Maintainer(String name, Duration interval, Clock clock, JobControl jobControl, JobMetrics jobMetrics, List<String> clusterHostnames, boolean ignoreCollision, double successFactorBaseline, boolean acquireLock)

Method Summary

Modifier and Type	Method	Description
protected final double	asSuccessFactorDeviation(int attempts, int failures)	Convenience methods to convert attempts and failures into a success factor deviation from the baseline, and return
void	awaitShutdown()	Waits for shutdown to complete, calling shutdown() if this hasn't been done already.
final void	doMaintain(boolean force)	Run this while holding the job lock, as necessary
protected Duration	interval()	Returns the interval at which this job is set to run
protected abstract double	maintain()	Called once each time this maintenance job should run.
final String	name()	Returns the simple name of this job
void	run()
void	shutdown()	Starts shutdown of this, typically by shutting down executors.
final boolean	shuttingDown()	Returns whether this is being shut down
final String	toString()

Methods inherited from class java.lang.Object

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

Field Details

log

protected final Logger log

Constructor Details

Maintainer

public Maintainer(String name,
 Duration interval,
 Clock clock,
 JobControl jobControl,
 JobMetrics jobMetrics,
 List<String> clusterHostnames,
 boolean ignoreCollision,
 double successFactorBaseline,
 boolean acquireLock)

Maintainer

public Maintainer(String name,
 Duration interval,
 Clock clock,
 JobControl jobControl,
 JobMetrics jobMetrics,
 List<String> clusterHostnames,
 boolean ignoreCollision)

Method Details

run

public void run()

Specified by:

run in interface Runnable

shutdown

public void shutdown()

Starts shutdown of this, typically by shutting down executors. awaitShutdown() waits for shutdown to complete.

awaitShutdown

public void awaitShutdown()

Waits for shutdown to complete, calling shutdown() if this hasn't been done already.

shuttingDown

public final boolean shuttingDown()

Returns whether this is being shut down

toString

public final String toString()

Overrides:

toString in class Object

maintain

protected abstract double maintain()

Called once each time this maintenance job should run.

Returns:

the degree to which the run successFactor deviated from the successFactorBaseline - a number between -1 (no success), to 0 (complete success) measured against the successFactorBaseline, or higher if the success factor is higher than the successFactorBaseline. The default successFactorBaseline is 1.0. If a maintainer is expected to fail sometimes, the successFactorBaseline should be set to a lower value. Note that this indicates whether something is wrong, so e.g. if the call did nothing because it should do nothing, 0.0 should be returned.

asSuccessFactorDeviation

protected final double asSuccessFactorDeviation(int attempts,
 int failures)

Convenience methods to convert attempts and failures into a success factor deviation from the baseline, and return

interval

protected Duration interval()

Returns the interval at which this job is set to run

doMaintain

public final void doMaintain(boolean force)

Run this while holding the job lock, as necessary

name

public final String name()

Returns the simple name of this job