in api/src/main/java/com/spotify/metrics/core/MetricIdCache.java [339:356]
public Any mapBuilder(final MapBuilder mapBuilder) {
if (mapBuilder == null) {
throw new IllegalArgumentException("'mapBuilder' must not be null");
}
return new Any(metricId, new CacheBuilder() {
@Override
public <T> Cache<T> build(Loader<T> loader) {
final ConcurrentMap<T, MetricId> map = mapBuilder.build();
if (map == null) {
throw new IllegalStateException("'mapBuilder' must not return null");
}
return new ConcurrentMapCache<T>(map, loader);
}
});
}