ObservableCounter<T extends num> class

ObservableCounter is an asynchronous instrument that reports monotonically increasing values when observed.

An ObservableCounter is used to measure monotonically increasing values where measurements are made by a callback function. For example, CPU time, bytes received, or number of operations.

Implemented types

• APIObservableCounter<T>
• SDKObservableInstrument

Constructors

ObservableCounter({required APIObservableCounter<T> apiCounter, required Meter meter})

Creates a new ObservableCounter instance.

Properties

advisory → InstrumentAdvisory?

Returns the advisory parameters of this observable counter.

no setter, override

callbacks → List<ObservableCallback<T>>

Returns the current list of callbacks registered to this instrument.

no setter, override

description → String?

Returns the description of this observable counter.

no setter, override

hashCode → int

The hash code for this object.

no setter, inherited

meter → APIMeter

Returns the meter that created this observable counter.

no setter, override

name → String

Returns the name of this observable counter.

no setter, override

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

unit → String?

Returns the unit of this observable counter.

no setter, override

Methods

addCallback(ObservableCallback<T> callback) → APICallbackRegistration<T>

Registers a callback function that will be invoked when the instrument is observed. Returns a registration handle that can be used to unregister the callback.

override

collect() → List<Measurement<T>>

Collects measurements from all registered callbacks and from any batch callbacks that observed this instrument since the last collection.

override

collectMetrics() → List<Metric>

Collects metrics for the SDK metric export.

override

collectPoints() → List<MetricPoint<T>>

Gets the current points for this counter. This is used by the SDK to collect metrics.

getValue([Attributes? attributes]) → T

Gets the current value of the counter for a specific set of attributes. If no attributes are provided, returns the sum of all recorded values.

isEnabled() → bool

Returns whether the instrument is enabled and will record measurements.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

observeFromBatch(num value, Attributes? attributes) → void

Queues a measurement observed by a batch callback for the next collection. The value is converted to the instrument's numeric type.

override

removeCallback(ObservableCallback<T> callback) → void

Removes a callback from this instrument by direct reference.

override

reset() → void

Resets the counter. This is only used for testing.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited