Package io.micrometer.core.instrument.binder.cache

Class CacheMeterBinder<C>

java.lang.Object

io.micrometer.core.instrument.binder.cache.CacheMeterBinder<C>

All Implemented Interfaces:

MeterBinder

Direct Known Subclasses:

CaffeineCacheMetrics, EhCache2Metrics, GuavaCacheMetrics, HazelcastCacheMetrics, JCacheMetrics

@NonNullApi
@NonNullFields
public abstract class CacheMeterBinder<C>
extends Object
implements MeterBinder

A common base class for cache metrics that ensures that all caches are instrumented with the same basic set of metrics while allowing for additional detail that is specific to an individual implementation.

Having this common base set of metrics ensures that you can reason about basic cache performance in a dimensional slice that spans different cache implementations in your application.

Constructor Summary

Constructors

Constructor	Description
CacheMeterBinder(C cache, String cacheName, Iterable<Tag> tags)

Method Summary

Modifier and Type	Method	Description
protected abstract void	bindImplementationSpecificMetrics(MeterRegistry registry)	Bind detailed metrics that are particular to the cache implementation, e.g.
final void	bindTo(MeterRegistry registry)
protected abstract Long	evictionCount()
protected C	getCache()
protected Iterable<Tag>	getTagsWithCacheName()
protected abstract long	hitCount()
protected abstract Long	missCount()
protected abstract long	putCount()	The put mechanism is unimportant - this count applies to entries added to the cache according to a pre-defined load function such as exists in Guava/Caffeine caches as well as manual puts.
protected abstract Long	size()	MOST cache implementations provide a means of retrieving the number of entries.

Methods inherited from class java.lang.Object

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

Constructor Details

CacheMeterBinder

public CacheMeterBinder(C cache,
 String cacheName,
 Iterable<Tag> tags)

Method Details

getCache

@Nullable
protected C getCache()

bindTo

public final void bindTo(MeterRegistry registry)

Specified by:

bindTo in interface MeterBinder

size

@Nullable
protected abstract Long size()

MOST cache implementations provide a means of retrieving the number of entries. Even if

Returns:

Total number of cache entries. This value may go up or down with puts, removes, and evictions. Returns null if the cache implementation does not provide a way to track cache size.

hitCount

protected abstract long hitCount()

Returns:

Get requests that resulted in a "hit" against an existing cache entry. Monotonically increasing hit count.

missCount

@Nullable
protected abstract Long missCount()

Returns:

Get requests that resulted in a "miss", or didn't match an existing cache entry. Monotonically increasing count. Returns null if the cache implementation does not provide a way to track miss count, especially in distributed caches.

evictionCount

@Nullable
protected abstract Long evictionCount()

Returns:

Total number of entries that have been evicted from the cache. Monotonically increasing eviction count. Returns null if the cache implementation does not support eviction, or does not provide a way to track the eviction count.

putCount

protected abstract long putCount()

The put mechanism is unimportant - this count applies to entries added to the cache according to a pre-defined load function such as exists in Guava/Caffeine caches as well as manual puts. Note that Guava/Caffeine caches don't count manual puts.

Returns:

Total number of entries added to the cache. Monotonically increasing count.

bindImplementationSpecificMetrics

protected abstract void bindImplementationSpecificMetrics(MeterRegistry registry)

Bind detailed metrics that are particular to the cache implementation, e.g. load duration for Caffeine caches, heap and disk size for EhCache caches. These metrics are above and beyond the basic set of metrics that is common to all caches.

Parameters:

registry - The registry to bind metrics to.

getTagsWithCacheName

protected Iterable<Tag> getTagsWithCacheName()