com.berryworks.jquantify

Class SessionCounter

java.lang.Object

com.berryworks.jquantify.Metric

com.berryworks.jquantify.EventCounter

com.berryworks.jquantify.SessionCounter

All Implemented Interfaces:

Serializable

public class SessionCounter
extends EventCounter

This class is used to count and observe the frequency, duration, and concurrency of events that have distinct start/stop times.

SessionCounter events may overlap. In other words, a second event may start before the first one stops. For a given SessionCounter, its concurrency is the number of events that have started and not yet stopped.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.berryworks.jquantify.EventCounter

mCurrentInterval, mNow, mPeakEvents, mPriorInterval

Fields inherited from class com.berryworks.jquantify.Metric

intervalSeconds, startTime, totalIntervals

Constructor Summary

Constructors

Constructor and Description
SessionCounter()
SessionCounter(String inLabel) Constructs a new SessionCounter.
SessionCounter(String inLabel, int inIntervalSeconds) Constructor for the SessionCounter object

Method Summary

Methods

Modifier and Type	Method and Description
void	add(int inIgnored) Counts the beginning of a session.
protected void	createIntervals()
long	getConcurrency() Gets the current concurrency, the number of sessions that have been added (started) without having yet been removed (stopped).
long	getMaximumSessionStartTime()
long	getMaximumSessionTime() Gets the number of milliseconds that elapsed during the longest completed session.
long	getPeakConcurrency() Gets the peak concurrency observed over the life of the metric.
SessionCounterInterval	getPeakConcurrencyInterval() Gets the interval in which the highest concurrency was noted.
long	getRecentSessionTime() Gets the number of milliseconds that a recent completed session took.
static SessionCounter	getSessionCounter(String inLabel) Get an instance of a SessionCounter with a particular label from the MetricRepository, creating one if necessary.
static SessionCounter	getSessionCounter(String inLabel, int inIntervalSeconds) Get an instance of a SessionCounter with a particular label from the MetricRepository.
float	getSessionTime() Gets the number of milliseconds of elapsed time spent within sessions observed by this SessionCounter.
float	getSessionTimeMean() Gets the mean session time in milliseconds.
protected void	normalizeCurrent_ScenarioA()
protected void	normalizeCurrent_ScenarioB()
protected void	normalizePrior_ScenarioA()
protected void	normalizePrior_ScenarioB(long nEmptyIntervals)
void	remove() Removes a single event.
void	remove(int inCount) Informs this EventCounter that a previously added event is "finished" and no longer among the concurrent events.
void	reset() Reset this SessionCounter to its "zero" condition so that it can be reused, avoiding the overhead of constructing a new instance.
void	start() Functionally identical to add(), supporting the start/stop terminology which is more natural then add/remove when the emphasis is on measuring elapsed time within critical sections.
void	stop() Functionally identical to remove().

Methods inherited from class com.berryworks.jquantify.EventCounter

getCount, getCumulativeEvents, getCumulativeFreq, getCurrentFreq, getCurrentInterval, getEventCounter, getPeakEvents, getPeakEventsInterval, normalize

Methods inherited from class com.berryworks.jquantify.Metric

add, getAge, getAgeMillis, getIntervalSeconds, getLabel, getTotalIntervals, setLabel, uptime

Methods inherited from class java.lang.Object

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

Constructor Detail

SessionCounter

public SessionCounter()

SessionCounter

public SessionCounter(String inLabel,
              int inIntervalSeconds)

Constructor for the SessionCounter object

Parameters:

inLabel - Descriptive label for this SessionCounter

inIntervalSeconds - number of seconds in each interval of this SessionCounter

SessionCounter

public SessionCounter(String inLabel)

Constructs a new SessionCounter.

Parameters:

inLabel - Description of the Parameter

Method Detail

getSessionCounter

public static SessionCounter getSessionCounter(String inLabel)

Get an instance of a SessionCounter with a particular label from the MetricRepository, creating one if necessary.

Parameters:

inLabel - - descriptive label for this SessionCounter

Returns:

The sessionCounter value

getSessionCounter

public static SessionCounter getSessionCounter(String inLabel,
                               int inIntervalSeconds)

Get an instance of a SessionCounter with a particular label from the MetricRepository. If that SessionCounter does not already exist, one is created with the given label and the designated interval size.

Parameters:

inLabel - - descriptive label for this SessionCounter

inIntervalSeconds - number of seconds in each interval of this SessionCounter

Returns:

The sessionCounter value

reset

public void reset()

Reset this SessionCounter to its "zero" condition so that it can be reused, avoiding the overhead of constructing a new instance.

Overrides:

reset in class EventCounter

getConcurrency

public long getConcurrency()

Gets the current concurrency, the number of sessions that have been added (started) without having yet been removed (stopped).

Returns:

The concurrency value

getPeakConcurrency

public long getPeakConcurrency()

Gets the peak concurrency observed over the life of the metric. A convenience method equivalent to getPeakConcurrencyInterval().getPeakConcurrency()

Returns:

The peakConcurrency value

getPeakConcurrencyInterval

public SessionCounterInterval getPeakConcurrencyInterval()

Gets the interval in which the highest concurrency was noted.

Returns:

Interval - having the highest concurrency

getSessionTime

public float getSessionTime()

Gets the number of milliseconds of elapsed time spent within sessions observed by this SessionCounter. Incomplete sessions -- those that have been started and not stopped -- are not included.

Returns:

sum of session times for all completed sessions

getRecentSessionTime

public long getRecentSessionTime()

Gets the number of milliseconds that a recent completed session took. If sessions are happening concurrently, then this implementation may not be able to give a correct value; if this is the case, 0 is returned.

Returns:

The recentSessionTime value

getMaximumSessionTime

public long getMaximumSessionTime()

Gets the number of milliseconds that elapsed during the longest completed session. If sessions are happening concurrently, then this implementation cannot give a correct value and 0 is returned.

Returns:

The maximumSessionTime value

getMaximumSessionStartTime

public long getMaximumSessionStartTime()

getSessionTimeMean

public float getSessionTimeMean()

Gets the mean session time in milliseconds. In other words, the average amount of time spent within a session. Sessions that have not completed are not included in the computation.

Returns:

The sessionTimeMean value

add

public void add(int inIgnored)

Counts the beginning of a session.

The implementation supports adding only one session at a time. Hence, the argument is ignored and treated as 1.

Overrides:

add in class EventCounter

Parameters:

inIgnored - - ignored for SessionCounter

start

public void start()

Functionally identical to add(), supporting the start/stop terminology which is more natural then add/remove when the emphasis is on measuring elapsed time within critical sections.

stop

public void stop()

Functionally identical to remove(). See start().

remove

public void remove(int inCount)

Informs this EventCounter that a previously added event is "finished" and no longer among the concurrent events. The argument is ignored.

Parameters:

inCount - - number of events to be removed

remove

public void remove()

Removes a single event. Equivalent to remove(1).

createIntervals

protected void createIntervals()

Overrides:

createIntervals in class EventCounter

normalizeCurrent_ScenarioA

protected void normalizeCurrent_ScenarioA()

Overrides:

normalizeCurrent_ScenarioA in class EventCounter

normalizePrior_ScenarioA

protected void normalizePrior_ScenarioA()

Overrides:

normalizePrior_ScenarioA in class EventCounter

normalizeCurrent_ScenarioB

protected void normalizeCurrent_ScenarioB()

Overrides:

normalizeCurrent_ScenarioB in class EventCounter

normalizePrior_ScenarioB

protected void normalizePrior_ScenarioB(long nEmptyIntervals)

Overrides:

normalizePrior_ScenarioB in class EventCounter