org.gridlab.gat.monitoring
Class Metric

java.lang.Object
  org.gridlab.gat.monitoring.Metric

All Implemented Interfaces:

Serializable

public class Metric
extends Object
implements Serializable

An instance of this class represents a measurable quantity within a monitoring system. There are two classes of metrics a monitoring system must deal with:

• Local metrics --- Local metrics are metrics that are directly measured on a resource. These can be highly dependent on the physical parameters of the resource. Thus, local metrics originating from two different resources are not necessarily comparable ( E.g. 1 hour CPU time on a 1 GHz Intel processor is different than 1 hour CPU time on an 800 MHz PPC processor although the numeric values are equal.) However resource administrators who know the configuration of the resource need local metrics for detailed monitoring of the status and operation of the resource.
• Grid metrics --- Grid metrics are metrics that have predefined semantics, thus they are resource independent. Grid metrics are derived from one or more local metrics by applying a specific, well defined algorithm (such as unit conversion, aggregation or averaging). Because of this transformation grid metrics may have less precision or they could be less specific but are guaranteed to be comparable between different resources. Unlike local metrics which a local resource is free to change grid metrics must be agreed upon, standardized and introduced by community consensus.

Instances of this class deal with both classes of metrics.

A metric definition contains the following information:

• Metric parameters
• Metric measurement frequency

Metric parameters The Metric parameters field in the metric definition contains the formal definition of the metric parameters. Many metrics can be measured at different places simultaneously. For example, CPU utilisation can be measured on several hosts or grid resources. The metric parameters can be used to distinguish between these different metric instances.

See Also:

Serialized Form

Constructor Summary

Metric(MetricDefinition definition, Map<String,Object> metricParameters)
Constructs a Metric instance from the passed Metric name and concrete values for the Metric parameters.

Metric(MetricDefinition definition, Map<String,Object> metricParameters, long frequency)
Constructs a Metric instance from the passed Metric name and concrete values for the Metric parameters.

Method Summary

boolean	equals(Object object) Tests this Metric for equality with the passed Object.
MetricDefinition	getDefinition() Gets the MetricDefinition.
long	getFrequency() Gets the measurement frequency in milliseconds.
Object	getMetricParameterByName(String name) Gets the Metric parameter value associated with the passed Metric parameter name.
Map<String,Object>	getMetricParameters() Gets the Metric parameters associated with this Metric.
String	toString()

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Metric

public Metric(MetricDefinition definition,
              Map<String,Object> metricParameters)

Constructs a Metric instance from the passed Metric name and concrete values for the Metric parameters. This constructor is used for DISCRETE metrics. Hence, there is no frequency specified.

The passed Metric name must be equal, as determined by String.equals(Object), to the Metric name in the desired target MetricDefinition. In addition, the passed concrete values for the Metric parameters must be of the same name and type as the Metric parameters in the desired target MetricDefinition. Also, all the required Metric parameters as specified in the MetricDefinition must be present.

Parameters:

definition - The MetricDefinition to create an instance of

metricParameters - The Metric parameters, a Map, for the desired MetricDefinition.

Metric

public Metric(MetricDefinition definition,
              Map<String,Object> metricParameters,
              long frequency)

Constructs a Metric instance from the passed Metric name and concrete values for the Metric parameters. This constructor is used for CONTINUOUS metrics. Hence, the frequency must be specified.

The passed Metric name must be equal, as determined by String.equals(Object), to the Metric name in the desired target MetricDefinition. In addition, the passed concrete values for the Metric parameters must be of the same name and type as the Metric parameters in the desired target MetricDefinition. Also, all the required Metric parameters as specified in the MetricDefinition must be present.

Parameters:

definition - The MetricDefinition to create an instance of

metricParameters - The Metric parameters, a Map, for the desired MetricDefinition

frequency - The measuring frequency.

Method Detail

equals

public boolean equals(Object object)

Tests this Metric for equality with the passed Object.

If the given object is not a Metric, then this method immediately returns false.

For two Metric instances to be considered as equal they must have equal descriptors, parameters and frequency.

Overrides:

equals in class Object

Parameters:

object - The Object to test for equality

Returns:

A boolean indicating equality

getMetricParameters

public Map<String,Object> getMetricParameters()

Gets the Metric parameters associated with this Metric.

Returns:

The Metric parameters, a Map

getFrequency

public long getFrequency()

Gets the measurement frequency in milliseconds.

Returns:

the measurement frequency in milliseconds.

getMetricParameterByName

public Object getMetricParameterByName(String name)

Gets the Metric parameter value associated with the passed Metric parameter name. The value null is returned if there is no Metric parameter value with the passed name.

Parameters:

name - The Metric parameter name, a String, for which to obtain the associated Metric

Returns:

The Metric parameter value, an Object, associated with the passed Metric parameter name.

getDefinition

public MetricDefinition getDefinition()

Gets the MetricDefinition.

Returns:

the MetricDefinition

toString

public String toString()

Overrides:

toString in class Object