System +attributes

System information is represented as system attributes. Each system +attribute consists of an entity and a key. The entity broadly +represents a device component or feature, such as battery or connectivity. +The key is an attribute of the entity. Entities can have multiple keys, with +each entity-key pair representing a single system attribute. For example, +battery strength and charging status are attributes of battery. The system +attributes for these are Battery - BatteryStrength and Battery +- ChargingStatus, respectively (see Table: +Battery system attributes). Each system attribute has a value that +contains data about the attribute. For some system attributes, the value can +be modified.

For more information about the supported system attributes, see section Supported system attributes (entities and keys).

For more information about the system data types that determine system +attribute values, see section System data types.

In JavaScript, +a system attribute is represented as an object, with the entity, key, and +value as properties of that object:

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**Table:** System attribute +object
+ Property +	+ Description +	+ Type +	+ Value +
+ `Entity` +	+ Specifies the entity of the system attribute. + Together with `Key`, this specifies the system attribute. +	+ string +	+ For a complete list of supported entities, see section Supported system attributes (entities and keys). +
+ `Key` +	+ Specifies the key of the system attribute. The available keys depend +on the entity. + Together with `Entity`, this specifies the system +attribute. +	+ string +	+ For a complete list of supported keys per entity, see the Key column +of the tables in section Supported system attributes (entities and keys). +
+ <`Value`> +	+ Specifies the value of the system attribute. + + The name, type, and content of this property depend on the system attribute +and whether the system attribute object is used as input or output: + INPUT + If the system attribute object is used as input for a method call, this +property is an object named `SystemData`. The actual system +attribute value is represented as one or more properties of the `SystemData` object. +The exact set of properties depends on the specific +system attribute and its system +data type for input. + For example: If you input the `Battery - BatteryStrength` system +attribute, whose input data type is `Status`, the `criteria` argument takes the following +properties: + + `criteria.Entity` + + `criteria.Key` + + `criteria.SystemData.Status` + + + Here, `criteria` is the input object representing +the system attribute, `SystemData` is the object containing +the system attribute value, and `Status` is the object +property specifying the actual value (as defined by the system data type). + Similarly, if you input the `Memory - DriveInfo` system +attribute, whose input data type is `DriveInfo`, the `criteria` argument takes the following +properties: + + `criteria.Entity` + + `criteria.Key` + + `criteria.SystemData.Drive` + + `criteria.SystemData.<...>` (other +properties associated with `DriveInfo`) + + OUTPUT + If the system attribute object is received as output from a method call, +the system attribute value is represented as one or more properties of the `ReturnValue` object +returned by the call. The exact set of properties depends on the specific +system attribute and its system +data type for output. + For example: If the `Battery - BatteryStrength` system +attribute, whose output data type is `Status`, is received as output, the `ReturnValue` object +contains the following properties: + + `ReturnValue.Entity` + `ReturnValue.Key` + `ReturnValue.Status` + + Here, `ReturnValue` is the output object representing +the system attribute, and `Status` is the object property +specifying the system attribute value (as defined by the system data type). + Similarly, if the `Memory - DriveInfo` system attribute, +whose output data type is `DriveInfo`, is received as output, the `ReturnValue` object +contains the following properties: + + `ReturnValue.Entity` + `ReturnValue.Key` + `ReturnValue.Drive` + `ReturnValue.TotalSpace` + `ReturnValue.FreeSpace` + `ReturnValue.CriticalSpace` + `ReturnValue.MediaType` + `ReturnValue.BatteryState` + `ReturnValue.DriveName` + +		+ See the Input and Output columns of the tables in section Supported system attributes (entities and keys). +