com.linecorp.armeria.internal.common.metric

Class MicrometerUtil

java.lang.Object

com.linecorp.armeria.internal.common.metric.MicrometerUtil

public final class MicrometerUtil
extends Object

A utility that prevents double instantiation of an object for a certain MeterIdPrefix. This can be useful when you need to make sure you do not register the same Meter more than once.

See Also:

RequestMetricSupport, CaffeineMetricSupport

Method Summary

Modifier and Type	Method and Description
static <T> T	register(MeterRegistry registry, MeterIdPrefix idPrefix, Class<T> type, BiFunction<MeterRegistry,MeterIdPrefix,T> factory) Associates a newly-created object with the specified MeterIdPrefix or returns an existing one if exists already.
static <T> void	registerLater(MeterRegistry registry, MeterIdPrefix idPrefix, Class<T> type, BiFunction<MeterRegistry,MeterIdPrefix,T> factory) Similar to register(MeterRegistry, MeterIdPrefix, Class, BiFunction), but used when a registration has to be nested, because otherwise the registration may enter an infinite loop, as described here.

Methods inherited from class java.lang.Object

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

Method Detail

register

public static <T> T register(MeterRegistry registry,
                             MeterIdPrefix idPrefix,
                             Class<T> type,
                             BiFunction<MeterRegistry,MeterIdPrefix,T> factory)

Associates a newly-created object with the specified MeterIdPrefix or returns an existing one if exists already.

Parameters:

idPrefix - the MeterIdPrefix of the object

type - the type of the object created by factory

factory - a factory that creates an object of type, to be associated with idPrefix

Returns:

the object of type, which may or may not be created by factory

Throws:

IllegalStateException - if there is already an object of different class associated for the same MeterIdPrefix

registerLater

public static <T> void registerLater(MeterRegistry registry,
                                     MeterIdPrefix idPrefix,
                                     Class<T> type,
                                     BiFunction<MeterRegistry,MeterIdPrefix,T> factory)

Similar to register(MeterRegistry, MeterIdPrefix, Class, BiFunction), but used when a registration has to be nested, because otherwise the registration may enter an infinite loop, as described here. For example:

 // OK
 register(registry, idPrefix, type, (r, i) -> {
     registerLater(registry, anotherIdPrefix, anotherType, ...);
     return ...;
 });

 // Not OK
 register(registry, idPrefix, type, (r, i) -> {
     register(registry, anotherIdPrefix, anotherType, ...);
     return ...;
 });