Struct KafkaMetric 

pub struct KafkaMetric { /* private fields */ }

A metric tracked by the registry. Holds a MetricName, a (mutable) MetricConfig and a MetricValueProvider.

In Java the config field is volatile and metricValue/measurableValue read under a per-metric lock to make the stat read consistent with sensor records. Because our simple stats are themselves lock-free (atomic), the value read needs no extra lock; we still guard config with a Mutex so the config(new) setter is observed atomically, matching Java’s synchronized setter + volatile read.

Implementations

impl KafkaMetric

pub fn config(&self) -> Arc<MetricConfig>

Get the configuration of this metric.

pub fn set_config(&self, config: Arc<MetricConfig>)

Set the metric config.

pub fn is_measurable(&self) -> bool

Determine if the metric value provider is of type Measurable.

pub fn measurable(&self) -> Result<&dyn Measurable, Error>

Get the underlying Measurable value provider.

Returns Error::LocalIllegalState when the provider is a MetricValueProvider::Gauge instead — Java’s measurable() throws IllegalStateException("Not a measurable: " + class) in that case (KafkaMetric.java). Per CLAUDE.md §12.2 an unchecked-but-recoverable Java exception becomes a Result rather than a panic.

Java returns the provider so callers can compare it by identity (see KafkaMetricTest.testIsMeasurable); Rust returns a borrow of the boxed trait object, which is the closest equivalent — trait objects have no meaningful value equality, so callers assert on is_ok() / the measured value instead.

Trait Implementations

impl Metric for KafkaMetric

fn metric_name(&self) -> &MetricName

A name for this metric.

fn metric_value(&self) -> MetricValue

The value of the metric, which may be measurable or a non-measurable gauge.