com.netflix.spectator.api.histogram.PercentileDistributionSummary Maven / Gradle / Ivy
/**
* Copyright 2015 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.netflix.spectator.api.histogram;
import com.netflix.spectator.api.Counter;
import com.netflix.spectator.api.DistributionSummary;
import com.netflix.spectator.api.Id;
import com.netflix.spectator.api.Measurement;
import com.netflix.spectator.api.Registry;
import java.util.Collections;
/**
* Distribution summary that buckets the counts to allow for estimating percentiles.
*/
public class PercentileDistributionSummary implements DistributionSummary {
/**
* Creates a distribution summary object that can be used for estimating percentiles.
*
* @param registry
* Registry to use.
* @param id
* Identifier for the metric being registered.
* @return
* Distribution summary that keeps track of counts by buckets that can be used to estimate
* the percentiles for the distribution.
*/
public static PercentileDistributionSummary get(Registry registry, Id id) {
return new PercentileDistributionSummary(registry, id);
}
private final Id id;
private final DistributionSummary summary;
private final Counter[] counters;
/** Create a new instance. */
PercentileDistributionSummary(Registry registry, Id id) {
this.id = id;
this.summary = registry.distributionSummary(id);
this.counters = new Counter[PercentileBuckets.length()];
for (int i = 0; i < counters.length; ++i) {
Id counterId = id.withTag("percentile", String.format("D%04X", i));
counters[i] = registry.counter(counterId);
}
}
@Override public Id id() {
return id;
}
@Override public Iterable measure() {
return Collections.emptyList();
}
@Override public boolean hasExpired() {
return summary.hasExpired();
}
@Override public void record(long amount) {
if (amount >= 0L) {
summary.record(amount);
counters[PercentileBuckets.indexOf(amount)].increment();
}
}
/**
* Computes the specified percentile for this distribution summary.
*
* @param p
* Percentile to compute, value must be {@code 0.0 <= p <= 100.0}.
* @return
* An approximation of the {@code p}`th percentile in seconds.
*/
public double percentile(double p) {
long[] counts = new long[PercentileBuckets.length()];
for (int i = 0; i < counts.length; ++i) {
counts[i] = counters[i].count();
}
return PercentileBuckets.percentile(counts, p);
}
@Override public long count() {
return summary.count();
}
@Override public long totalAmount() {
return summary.totalAmount();
}
}