com.bigdata.ganglia

Class TimestampMetricValue

java.lang.Object

com.bigdata.ganglia.TimestampMetricValue

All Implemented Interfaces:

ITimestampMetricValue

public class TimestampMetricValue
extends Object
implements ITimestampMetricValue

A reported or observed metric value with a timestamp. This is used to report metric values which are unchanged no more frequently than tmax seconds.

Note: This class deliberately does not use a generic for the data type. The data type of the last sampled value remains fluid within instances of this class. The data type will be converted to the IGangliaMetadataMessage.getMetricType() when an IGangliaMetricMessage is generated from the current value.

Constructor Summary

Constructors

Constructor and Description
TimestampMetricValue(IGangliaMetadataMessage decl)

Method Summary

Methods

Modifier and Type	Method and Description
int	getAge() The age in seconds of the last reported/received value (this reports seconds for compatibility with tmax and dmax, both of which also use seconds).
IGangliaMetadataMessage	getMetadata() The metadata declaration for this metric.
long	getTimestamp() The timestamp of the last reported/received value (milliseconds).
Object	getValue() The last reported/received value and null if no value has been reported/received.
int	priority() Return the priority.
void	resetTimestamp() Reset the timestamp.
boolean	setValue(Object newValue) Update the value associated with the metric.
String	toString() Human readable representation.
void	update() Update the timestamp.

Methods inherited from class java.lang.Object

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

Constructor Detail

TimestampMetricValue

public TimestampMetricValue(IGangliaMetadataMessage decl)

Method Detail

getMetadata

public IGangliaMetadataMessage getMetadata()

Description copied from interface: ITimestampMetricValue

The metadata declaration for this metric.

Specified by:

getMetadata in interface ITimestampMetricValue

getTimestamp

public long getTimestamp()

Description copied from interface: ITimestampMetricValue

The timestamp of the last reported/received value (milliseconds).

Note: Tmax is expressed in seconds, so be sure to do the conversion when necessary.

Specified by:

getTimestamp in interface ITimestampMetricValue

resetTimestamp

public void resetTimestamp()

Reset the timestamp. The next time the metric is updated it will self-report that it's value needs to be sent to ganglia listeners.

getAge

public int getAge()

Description copied from interface: ITimestampMetricValue

The age in seconds of the last reported/received value (this reports seconds for compatibility with tmax and dmax, both of which also use seconds).

Specified by:

getAge in interface ITimestampMetricValue

getValue

public Object getValue()

Description copied from interface: ITimestampMetricValue

The last reported/received value and null if no value has been reported/received.

Specified by:

getValue in interface ITimestampMetricValue

setValue

public boolean setValue(Object newValue)

Update the value associated with the metric.

This method handles any translation which must be applied to the value to bring it into line with the IGangliaMetadataMessage for the metric.

The as stored data type is not important as long as it remains either String or a Number. The IGangliaMessageEncoder is responsible for encoding the value according to the ganglia data type declaration in the IGangliaMetadataMessage.

Parameters:

newValue - The new value.

Returns:

true if the value changed enough to be worth reporting or if tmax has expired so we need to report the value anyway.

Throws:

IllegalArgumentException - if newValue is null.

IllegalArgumentException - if the metricType is numeric and newValue is not a Number.

update

public void update()

Update the timestamp.

priority

public int priority()

Return the priority. The priority orders metrics which have never been reported first (timestamp is ZERO) followed by metrics in descending tmax - age, where age is now - timestamp.

The highest priority is associated with the most negative value. The lowest priority is associated with the most positive value. These ar the semantics used by a PriorityBlockingQueue.

toString

public String toString()

Human readable representation.

Overrides:

toString in class Object