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CARP Documentation

Measure

Defines one type of data to collect passively as part of a task.

A measure names a data type (e.g., dk.cachet.carp.geolocation) and is added to a TaskConfiguration. When the task is triggered, the client collects this data type, typically through a probe.

Key points:

var task = BackgroundTask(measures: [
  Measure(type: CarpDataTypes.STEP_COUNT),
  Measure(type: CarpDataTypes.GEOLOCATION),
]);
Inheritance
Annotations

Constructors

Measure.fromJson

Measure.fromJson(
  1. Map<String, dynamic> json
)

Measure

Measure({
  1. required String type,
  2. SamplingConfiguration? samplingConfiguration,
})

Create a measure by specifying its type and optionally a samplingConfiguration to override the default sampling configuration.

Properties

dataType

  1. @JsonKey(includeFromJson: false, includeToJson: false)
DataType get dataType

The type of measure as a DataType.

fromJsonFunction

Function get fromJsonFunction
override

The function which can convert a JSON string to an object of this type.

hashCode

int get hashCode
override

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

jsonType

String get jsonType
override

Return the __type to be used for JSON serialization of this class. Default is runtimeType. Only specify this if you need another type.

overrideSamplingConfiguration

SamplingConfiguration? overrideSamplingConfiguration
getter/setter pair

Optionally, override the default configuration on how to sample the data stream of the matching type on the device. In case null is specified, the default configuration is derived from the DeviceConfiguration.

type

String type
getter/setter pair

The type of measure to do.

The fully qualified data type to collect, e.g., "dk.cachet.carp.geolocation". See CarpDataTypes for the core types.

Methods

toJson

Map<String, dynamic> toJson()
override

Return a JSON encoding of this object.

toString

String toString()
override

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Operators

operator ==

bool operator ==(
  1. Object other
)
override

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

  • Total: It must return a boolean for all arguments. It should never throw.

  • Reflexive: For all objects o, o == o must be true.

  • Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

  • Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.