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

Async state wrapper for a metric with one enum dimension (MetricType.ASYNC_GAUGE or MetricType.ASYNC_DOUBLE_GAUGE).

Two-callback contract (enforces cardinality control)

This class registers exactly ONE OTel observable gauge per metric entity. The caller provides:

1. AsyncMetricResolvers.LiveStateResolverOneEnum — maps an enum value to its backing state, or null when the combo is dormant. The null return is the liveness signal: the SDK never sees an attribute set for a dormant combo, so the cardinality cap is only charged for combos that actually have data.
2. AsyncMetricResolvers.ValueResolverOneEnum — reads the numeric value from the resolved state. Only invoked when AsyncMetricResolvers.LiveStateResolverOneEnum.resolve(E) returned non-null.

Splitting the two phases forces the caller to think about liveness: there is no path from "combo" to "value" that skips the state resolution, so it is impossible to accidentally emit a dormant attribute set.

Attribute sets are precomputed once per enum value at construction and cached. Per-collection cost is O(|E|) liveStateResolver calls plus one measurement.record(...) per emitted combo.

Method Summary

Modifier and Type	Method	Description
static <E extends Enum<E> & VeniceDimensionInterface, S> AsyncMetricEntityStateOneEnum<E>	create(MetricEntity metricEntity, VeniceOpenTelemetryMetricsRepository otelRepository, Map<VeniceMetricsDimensions,String> baseDimensionsMap, Class<E> enumTypeClass, AsyncMetricResolvers.LiveStateResolverOneEnum<E,S> liveStateResolver, AsyncMetricResolvers.ValueResolverOneEnum<S,E> valueResolver)	Creates a state wrapper and registers a single multi-emit observable gauge.
boolean	emitOpenTelemetryMetrics()
EnumMap<E,io.opentelemetry.api.common.Attributes>	getAttributesByEnum()	Visible for testing — the cached attributes per enum value, or null if OTel is disabled.
Object	getInstrument()	Visible for testing — the underlying SDK instrument handle, or null if OTel disabled.

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,
S>
AsyncMetricEntityStateOneEnum<E> create(MetricEntity metricEntity,
 VeniceOpenTelemetryMetricsRepository otelRepository,
 Map<VeniceMetricsDimensions,String> baseDimensionsMap,
 Class<E> enumTypeClass,
 AsyncMetricResolvers.LiveStateResolverOneEnum<E,S> liveStateResolver,
 AsyncMetricResolvers.ValueResolverOneEnum<S,E> valueResolver)

Creates a state wrapper and registers a single multi-emit observable gauge. On every collection the SDK invokes the callback, which for each enum value:

• calls liveStateResolver.resolve(enumValue) — if null, skips this combo for this cycle;
• otherwise calls valueResolver.extractValue(state, enumValue) and emits a data point with the precomputed attributes.

When OTel is disabled, no registration happens and neither callback is invoked.

Type Parameters:

S - the state type returned by liveStateResolver. Can be any reference type (wrapper, task, counter, etc.) — the infra never inspects it beyond null-check.

emitOpenTelemetryMetrics

public boolean emitOpenTelemetryMetrics()

getAttributesByEnum

public EnumMap<E,io.opentelemetry.api.common.Attributes> getAttributesByEnum()

Visible for testing — the cached attributes per enum value, or null if OTel is disabled.

getInstrument

public Object getInstrument()

Visible for testing — the underlying SDK instrument handle, or null if OTel disabled.