atg.service.statistics
Class Sampler

java.lang.Object
  atg.nucleus.logging.VariableArgumentApplicationLoggingImpl
      atg.nucleus.GenericService
          atg.nucleus.TimedOperationService
              atg.service.statistics.Sampler

All Implemented Interfaces:

NameContextBindingListener, NameContextElement, NameResolver, AdminableService, ApplicationLogging, atg.nucleus.logging.ApplicationLoggingSender, atg.nucleus.logging.TraceApplicationLogging, atg.nucleus.logging.VariableArgumentApplicationLogging, ComponentNameResolver, Service, ServiceListener, Schedulable, java.util.EventListener

public class Sampler
extends TimedOperationService
implements Schedulable

A Sampler is the base class for services that wish to keep a list of statistics about other services. The sampler is configured with a list of properties to be sampled. Each property is specified in the form {service name}.{property name}.The list is assigned to the property "sampleSources". For example:

 sampleSources=\
      /servers/HttpServer.handledRequestCount,\
      /requesthandling/FileCache.cacheHitRatio
 

On demand, the Sampler can sample all of the properties in the list and produce a SampleEvent, which contains the samples in the order they were specified.

The Sampler can also send out a SampleEvent as an event to all SampleListeners. This can happen on demand as well.

Finally, if Scheduler and Schedule properties are defined, then this Sampler will send out events to SampleListeners according to the given Schedule.

Field Summary

static java.lang.String	CLASS_VERSION Class version string
protected atg.service.statistics.Sampler.SampleSource[]	mSources The sample sources

Fields inherited from class atg.nucleus.GenericService

SERVICE_INFO_KEY

Fields inherited from interface atg.nucleus.logging.TraceApplicationLogging

DEFAULT_LOG_TRACE_STATUS

Fields inherited from interface atg.nucleus.logging.ApplicationLogging

DEFAULT_LOG_DEBUG_STATUS, DEFAULT_LOG_ERROR_STATUS, DEFAULT_LOG_INFO_STATUS, DEFAULT_LOG_WARNING_STATUS

Constructor Summary

Sampler()
Constructs a blank new Sampler

Method Summary

void	addSampleListener(SampleListener pListener) Adds a listener to the list of listeners to be notified when a new sample is taken.
void	doStartService() This will start the thread running
void	doStopService() This will stop the scheduler thread
protected Sample	getSample(atg.service.statistics.Sampler.SampleSource pSource, Sample pPreviousSample) Obtains a sample from the given source
int	getSampleListenerCount() Returns the number of sample listeners
SampleListener[]	getSampleListeners() Returns an array of the sample listeners
java.lang.String[]	getSampleSources() Returns the list of {service}.{property} values to be included in every sample.
Schedule	getSchedule() Returns the Schedule on which this sampler will run.
Scheduler	getScheduler() Returns the Scheduler that will run this sampler
void	initSources() Initializes the array of sources to be sampled from the SampleSources property
void	performScheduledTask(Scheduler pScheduler, ScheduledJob pJob) Obtains a sample and sends it to the listeners
void	removeSampleListener(SampleListener pListener) Removes a listener from the list of listeners to be notified when a new sample is taken.
SampleEvent	sample() Performs a sample on all of the sources in the sample list and returns the result without notifying the listeners.
SampleEvent	sample(boolean pNotifyListeners) Performs a sample on all of the sources in the sample list and returns the result.
void	setSampleSources(java.lang.String[] pSampleSources) Sets the list of {service}.{property} values to be included in every sample.
void	setSchedule(Schedule pSchedule) Sets the Schedule on which this sampler will run.
void	setScheduler(Scheduler pScheduler) Sets the Scheduler that will run this sampler

Methods inherited from class atg.nucleus.TimedOperationService

getAverageRequestHandlingTime, getHandledRequestCount, getRequestStartTime, getTotalRequestHandlingTime, isKeepingStatistics, notifyHandledRequest, resetStatistics, setKeepingStatistics

Methods inherited from class atg.nucleus.GenericService

addLogListener, createAdminServlet, getAbsoluteName, getAdminServlet, getLoggingForVlogging, getLogListenerCount, getLogListeners, getName, getNameContext, getNucleus, getRoot, getServiceConfiguration, getServiceInfo, isLoggingDebug, isLoggingError, isLoggingInfo, isLoggingTrace, isLoggingWarning, isRunning, logDebug, logDebug, logDebug, logError, logError, logError, logInfo, logInfo, logInfo, logTrace, logTrace, logTrace, logWarning, logWarning, logWarning, nameContextElementBound, nameContextElementUnbound, removeLogListener, resolveName, resolveName, resolveName, resolveName, sendLogEvent, setLoggingDebug, setLoggingError, setLoggingInfo, setLoggingTrace, setLoggingWarning, setNucleus, setServiceInfo, startService, stopService

Methods inherited from class atg.nucleus.logging.VariableArgumentApplicationLoggingImpl

vlogDebug, vlogDebug, vlogDebug, vlogDebug, vlogError, vlogError, vlogError, vlogError, vlogInfo, vlogInfo, vlogInfo, vlogInfo, vlogTrace, vlogTrace, vlogTrace, vlogTrace, vlogWarning, vlogWarning, vlogWarning, vlogWarning

Methods inherited from class java.lang.Object

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

Field Detail

CLASS_VERSION

public static java.lang.String CLASS_VERSION

Class version string

mSources

protected atg.service.statistics.Sampler.SampleSource[] mSources

The sample sources

Constructor Detail

Sampler

public Sampler()

Constructs a blank new Sampler

Method Detail

sample

public SampleEvent sample(boolean pNotifyListeners)
                   throws ServiceException

Performs a sample on all of the sources in the sample list and returns the result.

Parameters:

pNotifyListeners - if true, then all SampleListeners will also be notified.

Throws:

ServiceException - if an error occurred while obtaining a sample.

sample

public SampleEvent sample()
                   throws ServiceException

Performs a sample on all of the sources in the sample list and returns the result without notifying the listeners.

Throws:

ServiceException - if an error occurred while obtaining a sample.

getSample

protected Sample getSample(atg.service.statistics.Sampler.SampleSource pSource,
                           Sample pPreviousSample)
                    throws ServiceException

Obtains a sample from the given source

Throws:

ServiceException - if an error occurred while obtaining the sample.

performScheduledTask

public void performScheduledTask(Scheduler pScheduler,
                                 ScheduledJob pJob)

Obtains a sample and sends it to the listeners

Specified by:

performScheduledTask in interface Schedulable

Parameters:

pScheduler - calling the job

pJob - the ScheduledJob

setSampleSources

public void setSampleSources(java.lang.String[] pSampleSources)

Sets the list of {service}.{property} values to be included in every sample.

getSampleSources

public java.lang.String[] getSampleSources()

Returns the list of {service}.{property} values to be included in every sample.

setScheduler

public void setScheduler(Scheduler pScheduler)

Sets the Scheduler that will run this sampler

getScheduler

public Scheduler getScheduler()

Returns the Scheduler that will run this sampler

setSchedule

public void setSchedule(Schedule pSchedule)

Sets the Schedule on which this sampler will run.

getSchedule

public Schedule getSchedule()

Returns the Schedule on which this sampler will run.

addSampleListener

public void addSampleListener(SampleListener pListener)

Adds a listener to the list of listeners to be notified when a new sample is taken.

removeSampleListener

public void removeSampleListener(SampleListener pListener)

Removes a listener from the list of listeners to be notified when a new sample is taken.

getSampleListenerCount

public int getSampleListenerCount()

Returns the number of sample listeners

getSampleListeners

public SampleListener[] getSampleListeners()

Returns an array of the sample listeners

doStartService

public void doStartService()
                    throws ServiceException

This will start the thread running

Overrides:

doStartService in class GenericService

Throws:

ServiceException - if the Service had a problem starting up

initSources

public void initSources()
                 throws ServiceException

Initializes the array of sources to be sampled from the SampleSources property

Throws:

ServiceException

doStopService

public void doStopService()

This will stop the scheduler thread

Overrides:

doStopService in class GenericService