com.sun.enterprise.admin.monitor.stats

Class MutableBoundedRangeStatisticImpl

java.lang.Object

com.sun.enterprise.admin.monitor.stats.MutableBoundedRangeStatisticImpl

All Implemented Interfaces:

MutableCountStatistic, MutableStatistic, Serializable, BoundaryStatistic, BoundedRangeStatistic, RangeStatistic, Statistic

public class MutableBoundedRangeStatisticImpl
extends Object
implements BoundedRangeStatistic, MutableCountStatistic

An implementation of MutableCountStatistic that provides ways to change the state externally through mutators. Convenience class that is useful for components that gather the statistical data. By merely changing the count (which is a mandatory measurement), rest of the statistical information could be deduced.

Since:

S1AS8.0

Version:

1.0

Author:

Kedar Mhaswade

See Also:

for an immutable implementation, Serialized Form

Constructor Summary

Constructors

Constructor and Description
MutableBoundedRangeStatisticImpl(BoundedRangeStatistic initial) Constructs an instance of MutableCountStatistic that encapsulates the given Statistic.

Method Summary

Methods

Modifier and Type	Method and Description
long	getCurrent() The current value of this attribute.
String	getDescription() A human-readable description of the Statistic.
long	getHighWaterMark() The highest value this attribute has held since the beginning of the measurement.
long	getLastSampleTime() The time of the last measurement represented as a long, whose value is the number of milliseconds since January 1, 1970, 00:00:00.
long	getLowerBound() The lower limit of the value of this attribute.The upper limit of the value of this attribute.
long	getLowWaterMark() The lowest value this attribute has held since the beginning of the measurement.
String	getName() The name of this Statistic.
long	getStartTime() The time of the first measurement represented as a long, whose value is the number of milliseconds since January 1, 1970, 00:00:00.
String	getUnit() The unit of measurement for this Statistic.
long	getUpperBound() The upper limit of the value of this attribute.
Statistic	modifiableView() Returns an instance of Statistic whose state can be changed by the caller.
void	reset() Resets to the initial state.
void	setCount(long current) Changes the current value of the encapsulated BoundedRangeStatistic to the given value.
void	setDescription(String s)
Statistic	unmodifiableView() This method is the essence of this class.

Methods inherited from class java.lang.Object

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

Constructor Detail

MutableBoundedRangeStatisticImpl

public MutableBoundedRangeStatisticImpl(BoundedRangeStatistic initial)

Constructs an instance of MutableCountStatistic that encapsulates the given Statistic. The only parameter denotes the initial state of this statistic. It is guaranteed that the initial state is preserved internally, so that one can reset to the initial state.

Parameters:

initial - an instance of BoundedRangeStatistic that represents initial state

Method Detail

reset

public void reset()

Resets to the initial state. It is guaranteed that following changes occur to the statistic if this method is called:

• The current value is reset to initial value.
• The lastSampleTime is reset to current time in milliseconds.
• The startTime is reset to lastSampleTime.
• The highWaterMark is reset to the initial value.
• The lowWaterMark is reset to the initial value.

The remaining meta data in the encapsulated statistic is unchanged. The upper and lower bounds are untouched.

Specified by:

reset in interface MutableStatistic

setCount

public void setCount(long current)

Changes the current value of the encapsulated BoundedRangeStatistic to the given value. Since this is the only mutator exposed here, here are the other side effects of calling this method:

• lastSampleTime is set to current time in milliseconds.
• highWaterMark is accordingly adjusted.
• lowWaterMark is accordingly adjusted.

In a real-time system with actual probes for measurement, the lastSampleTime could be different from the instant when this method is called, but that is deemed insignificant.

Specified by:

setCount in interface MutableCountStatistic

Parameters:

count - long that represents the current value of the Statistic.

unmodifiableView

public Statistic unmodifiableView()

This method is the essence of this class. It provides the read-only view of encapsulated Statistic. If the clients have to know the Statistic, this is what should be called by actual data collecting component to return the value to them. The principle advantage is from the data collecting component's standpoint, in that it does not have to create instances of BoundedRangeStatistic when its current value is queried/measured.

Specified by:

unmodifiableView in interface MutableStatistic

Returns:

instance of BoundedRangeStatistic

See Also:

reset(), setCount(long)

getDescription

public String getDescription()

Description copied from interface: Statistic

A human-readable description of the Statistic.

Specified by:

getDescription in interface Statistic

getLastSampleTime

public long getLastSampleTime()

Description copied from interface: Statistic

The time of the last measurement represented as a long, whose value is the number of milliseconds since January 1, 1970, 00:00:00.

Specified by:

getLastSampleTime in interface Statistic

getName

public String getName()

Description copied from interface: Statistic

The name of this Statistic.

Specified by:

getName in interface Statistic

getStartTime

public long getStartTime()

Description copied from interface: Statistic

The time of the first measurement represented as a long, whose value is the number of milliseconds since January 1, 1970, 00:00:00.

Specified by:

getStartTime in interface Statistic

getUnit

public String getUnit()

Description copied from interface: Statistic

The unit of measurement for this Statistic. Valid values for TimeStatistic measurements are "HOUR", "MINUTE", "SECOND", "MILLISECOND", "MICROSECOND" and "NANOSECOND".

Specified by:

getUnit in interface Statistic

modifiableView

public Statistic modifiableView()

Description copied from interface: MutableStatistic

Returns an instance of Statistic whose state can be changed by the caller. It is important to know that caller should not cache the return value from this method. In general, there is a problem in this contract in that, a client would not know from a Stats.getCreateCount() method whether the return value is something that is being modified or is invariant. Hence the caller should not cache the returned value in a collection and then collectively process it. The main idea behind providing this method is to control the number of instances created (per Mahesh's Suggestion).

Specified by:

modifiableView in interface MutableStatistic

Returns:

an instance of Statistic interface that should not be cached.

getCurrent

public long getCurrent()

Description copied from interface: RangeStatistic

The current value of this attribute.

Specified by:

getCurrent in interface RangeStatistic

getHighWaterMark

public long getHighWaterMark()

Description copied from interface: RangeStatistic

The highest value this attribute has held since the beginning of the measurement.

Specified by:

getHighWaterMark in interface RangeStatistic

getLowWaterMark

public long getLowWaterMark()

Description copied from interface: RangeStatistic

The lowest value this attribute has held since the beginning of the measurement.

Specified by:

getLowWaterMark in interface RangeStatistic

getLowerBound

public long getLowerBound()

Description copied from interface: BoundaryStatistic

The lower limit of the value of this attribute.The upper limit of the value of this attribute.

Specified by:

getLowerBound in interface BoundaryStatistic

getUpperBound

public long getUpperBound()

Description copied from interface: BoundaryStatistic

The upper limit of the value of this attribute.

Specified by:

getUpperBound in interface BoundaryStatistic

setDescription

public void setDescription(String s)