com.spotify.metrics.core

Class MetricIdCache<T>

java.lang.Object

com.spotify.metrics.core.MetricIdCache<T>

Type Parameters:

T - The key type for loading the metric id.

public class MetricIdCache<T>
extends Object

A utility class that simplifies mutating and storing a MetricId.

Example

 // example using Guava.
 final MetricIdCache.CacheBuilder cacheBuilder = new MetricIdCache.CacheBuilder() {
     public  ConcurrentMap build() {
         return CacheBuilder.newBuilder()
             .expireAfterWrite(12, TimeUnit.HOURS).build().asMap()
     }
 };

 final MetricIdCache.Builder builder = MetricIdCache.builder().cacheBuilder(cacheBuilder);

 final MetricIdCache cache = builder.metricId(MetricId.build().tagged("foo", "bar"))
 .loader(new MetricIdCache.Loader() {
     public MetricId load(MetricId base, String key) {
         base.tagged("key", key);
     }
 }).build();

 cache.get("hello"); // MetricId(foo=bar, key=hello)
 cache.get("world"); // MetricId(foo=bar, key=world)

 // subsequent calls with cache.get("hello"), or cache.get("world") will return the same
 MetricId instance.
 

Author:

udoprog

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MetricIdCache.Any A metric id cache builder that can take any type.
static interface	MetricIdCache.Cache<T>
static interface	MetricIdCache.CacheBuilder
static interface	MetricIdCache.Loader<T>
static interface	MetricIdCache.MapBuilder
static class	MetricIdCache.Typed<T> A builder for which the metric id cache has a given type.

Method Summary

Modifier and Type	Method and Description
static MetricIdCache.Any	builder()
MetricId	get(T key) Get the value for the specified key.
void	invalidate(T key)
void	invalidateAll()

Methods inherited from class java.lang.Object

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

Method Detail

builder

public static MetricIdCache.Any builder()

get

public MetricId get(T key)

Get the value for the specified key.

This method is guaranteed to return the same instance of the associated MetricId, regardless of how many threads invoke it.

The configured Loader could be called multiple times, and should be idempotent to that.

Parameters:

key - The given key to get MetricId for.

Returns:

A metric id for the given key.

Throws:

IllegalStateException - if loader returns null.

invalidate

public void invalidate(T key)

invalidateAll

public void invalidateAll()