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monitoring::Metric Class Reference 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:. More... Collaboration diagram for monitoring::Metric: [legend]List of all members. Public Methods   Metric (String metricName, Map metricParameters)   Constructs a Metric instance from the passed Metric name and concrete values for the Metric parameters. boolean  equals (Object object)   Tests this Metric for equality with the passed Object. String  getMetricName ()   Gets the Metric name associated with this Metric. Map  getMetricParameters ()   Gets the Metric parameters associated with this Metric. Object  getMetricParameterByName (String name)   Gets the Metric parameter value associated with the passed Metric parameter name. Private Attributes String  metricName = null   This member variable holds the Metric name. Map  metricParameters = null   This member variable holds the Metric parameters. Detailed Description 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, standardised and introduced by community consensus. Instances of this class deal with both classes of metrics. A Metric can only be measured if there exists a sensor which can measure the quantity corresponding to the Metric. Such sensors are created by sensor developers and must embedded in a resource to allow the corresponding Metric or Metrics to be measured. (The creation of sensors is beyond the scope of this document and as such will not be covered.) Such sensors, once created, define the Metric or Metrics which they allow to be measured using a metric definitions. A metric definition contains the following information: Metric name Metric parameters Metric measurement type Metric data type Metric Unit Metric name The Metric name is used to identify the metric definition (e.g. CPU usage). It consists of dot separated words, e.g. host.cpu.user. The last component of a metric name is the actual name of the metric, the preceding components are called scope. The scope can be used to group metrics as well as to differentiate between similar metrics defined at different levels (for example, CPU utilisation can be measured on a per-job or per-host level). 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. Metric measurement type The Metric Measurement type can be <it>continuous</it> meaning data is always available or <it>event-like</it> meaning data only becomes available when some external event happens (e.g. a sensor embedded in an application can send events any time). Continuous metrics are only available using pull model delivery unless the user specifies a measurement frequency. (The reason for this is without a specified measurement frequency there is no event triggering the measurement of a continuous metric.) If the user asks for periodic measurements by specifying a measurement frequency the system will generate periodic events automatically. This avoids polling and allows the system to use the measurement frequency information to optimise measurements. Metric data type The Metric data type contains the definition of the storage used for representing measurement data. Metric Unit The Metric unit specifies the physical unit in which the metric is measured as a java.lang.String. It is only valid for simple numeric types and java.util.List's of these types. In the latter case it means the unit of all elements of the java.util.List. In using the Metric class one must make an instance of the Metric class. One does so using the Metric constructor; it takes the Metric name and concrete values for the Metric parameters and yields a Metric instance. The notion of Metric instances is necessary because the same metric could be measured at different places (e.g. on different hosts) at the same time. Metric instances are used to differentiate between these measurements, e.g. instances of a Metric describing the available memory on a host are distinguished by a parameter containing the hostname. Definition at line 84 of file Metric.java. Constructor & Destructor Documentation monitoring::Metric::Metric (  String    metricName, Map    metricParameters )  [inline]   Constructs a Metric instance from the passed Metric name and concrete values for the Metric parameters. The passed Metric name must be equal, as determined by the Equals method of the java.lang.String class, to the Metric name is the desired target Metric definition. 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 Metric definition. Also, all the required Metric parameters as specified in the Metric definition must be present. Parameters: metricName  The Metric name, a java.lang.String, of the desired target Metric definition metricParameters  The Metric parameters, a java.util.Map, for the desired Metric definition Definition at line 112 of file Metric.java. References monitoring::Metric::metricName, and monitoring::Metric::metricParameters. Member Function Documentation boolean monitoring::Metric::equals (  Object    object )  [inline]   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 Metric names, a java.lang.String, as determined my the Equals method on java.lang.String. In addition, they must have equal Metric parameters as determined by the Equals method on java.util.Map. Parameters: object  The Object to test for equality Returns: A boolean indicating equality Definition at line 130 of file Metric.java. References monitoring::Metric::metricName, and monitoring::Metric::metricParameters. String monitoring::Metric::getMetricName (    )  [inline]   Gets the Metric name associated with this Metric. Returns: The Metric name, a java.lang.String Definition at line 152 of file Metric.java. References monitoring::Metric::metricName. Map monitoring::Metric::getMetricParameters (    )  [inline]   Gets the Metric parameters associated with this Metric. Returns: The Metric parameters, a java.util.Map Definition at line 161 of file Metric.java. References monitoring::Metric::metricParameters. Object monitoring::Metric::getMetricParameterByName (  String    name )  [inline]   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 java.lang.String, for which to obtain the associated Metric Returns: The Metric parameter value, an Object, associated with the passed Metric parameter name. Definition at line 175 of file Metric.java. References monitoring::Metric::metricParameters. Member Data Documentation String monitoring::Metric::metricName = null [private]   This member variable holds the Metric name. Definition at line 89 of file Metric.java. Referenced by monitoring::Metric::equals(), monitoring::Metric::getMetricName(), and monitoring::Metric::Metric(). Map monitoring::Metric::metricParameters = null [private]   This member variable holds the Metric parameters. Definition at line 94 of file Metric.java. Referenced by monitoring::Metric::equals(), monitoring::Metric::getMetricParameterByName(), monitoring::Metric::getMetricParameters(), and monitoring::Metric::Metric(). The documentation for this class was generated from the following file: Metric.java