io.micrometer.core.instrument.distribution.TimeWindowPercentileHistogram Maven / Gradle / Ivy

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Application monitoring instrumentation facade
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/**
 * Copyright 2017 Pivotal Software, 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 io.micrometer.core.instrument.distribution;

import io.micrometer.core.instrument.Clock;
import org.HdrHistogram.DoubleHistogram;
import org.HdrHistogram.DoubleRecorder;

import java.io.PrintStream;

/**
 * A histogram implementation that supports the computation of percentiles by Micrometer for
 * publishing to a monitoring system.
 *
 * @author Jon Schneider
 * @author Trustin Heuiseung Lee
 */
public class TimeWindowPercentileHistogram extends AbstractTimeWindowHistogram {

    private final DoubleHistogram intervalHistogram;

    public TimeWindowPercentileHistogram(Clock clock, DistributionStatisticConfig distributionStatisticConfig,
                                         boolean supportsAggregablePercentiles) {
        super(clock, distributionStatisticConfig, DoubleRecorder.class, supportsAggregablePercentiles);
        intervalHistogram = new DoubleHistogram(percentilePrecision(distributionStatisticConfig));
        initRingBuffer();
    }

    @Override
    DoubleRecorder newBucket() {
        return new DoubleRecorder(percentilePrecision(distributionStatisticConfig));
    }

    @Override
    void recordDouble(DoubleRecorder bucket, double value) {
        bucket.recordValue(value);
    }

    @Override
    void recordLong(DoubleRecorder bucket, long value) {
        bucket.recordValue(value);
    }

    @Override
    void resetBucket(DoubleRecorder bucket) {
        bucket.reset();
    }

    @Override
    DoubleHistogram newAccumulatedHistogram(DoubleRecorder[] ringBuffer) {
        return new DoubleHistogram(percentilePrecision(distributionStatisticConfig));
    }

    @Override
    void accumulate() {
        currentHistogram().getIntervalHistogramInto(intervalHistogram);
        accumulatedHistogram().add(intervalHistogram);
    }

    @Override
    void resetAccumulatedHistogram() {
        accumulatedHistogram().reset();
    }

    @Override
    double valueAtPercentile(double percentile) {
        return accumulatedHistogram().getValueAtPercentile(percentile);
    }

    @Override
    double countAtValue(long value) {
        return accumulatedHistogram().getCountBetweenValues(0, value);
    }

    private int percentilePrecision(DistributionStatisticConfig config) {
        return config.getPercentilePrecision() == null ? 1 : config.getPercentilePrecision();
    }

    @Override
    void outputSummary(PrintStream out, double bucketScaling) {
        accumulatedHistogram().outputPercentileDistribution(out, bucketScaling);
    }
}