Package com.linkedin.venice.stats.metrics

Class AsyncMetricEntityStateOneEnum<E extends Enum<E> & VeniceDimensionInterface>

java.lang.Object

com.linkedin.venice.stats.metrics.AsyncMetricEntityStateOneEnum<E>

public class AsyncMetricEntityStateOneEnum<E extends Enum<E> & VeniceDimensionInterface>
extends Object

This class is used when the async metric (MetricType.ASYNC_GAUGE or MetricType.ASYNC_DOUBLE_GAUGE) has one dynamic dimension which is an Enum implementing VeniceDimensionInterface.

For each enum value, a separate AsyncMetricEntityStateBase is created with its own callback. This allows polling different values based on the dimension (e.g., different VersionRole values).

Callers always provide a DoubleSupplier callback. The factory dispatches to the correct OTel instrument type based on the MetricEntity's MetricType:

• ASYNC_GAUGE creates an ObservableLongGauge (value cast to long)
• ASYNC_DOUBLE_GAUGE creates an ObservableDoubleGauge (value used as-is)

EnumMap is used here as it is more efficient than HashMap as it is backed by an array and does not require hashing of the keys resulting in constant time complexity for get() and put() operations.

Method Summary

Modifier and Type	Method	Description
static <E extends Enum<E> & VeniceDimensionInterface> AsyncMetricEntityStateOneEnum<E>	create(MetricEntity metricEntity, VeniceOpenTelemetryMetricsRepository otelRepository, Map<VeniceMetricsDimensions,String> baseDimensionsMap, Class<E> enumTypeClass, Function<E,DoubleSupplier> callbackProvider)	Factory method that accepts a DoubleSupplier callback for each enum value.
boolean	emitOpenTelemetryMetrics()
AsyncMetricEntityStateBase	getMetricState(E enumValue)
EnumMap<E,AsyncMetricEntityStateBase>	getMetricStatesByEnum()	Visible for testing

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

create

public static <E extends Enum<E> & VeniceDimensionInterface>
AsyncMetricEntityStateOneEnum<E> create(MetricEntity metricEntity,
 VeniceOpenTelemetryMetricsRepository otelRepository,
 Map<VeniceMetricsDimensions,String> baseDimensionsMap,
 Class<E> enumTypeClass,
 Function<E,DoubleSupplier> callbackProvider)

Factory method that accepts a DoubleSupplier callback for each enum value. Dispatches to the correct OTel instrument type based on MetricEntity.getMetricType(): ASYNC_GAUGE wraps as long (no rounding — simple truncation cast), and ASYNC_DOUBLE_GAUGE passes the double directly.

Callers with long values can pass them directly in the lambda — Java auto-widens long to double, which is lossless for all practical metric values.

emitOpenTelemetryMetrics

public boolean emitOpenTelemetryMetrics()

getMetricState

public AsyncMetricEntityStateBase getMetricState(E enumValue)

getMetricStatesByEnum

public EnumMap<E,AsyncMetricEntityStateBase> getMetricStatesByEnum()

Visible for testing