io.prometheus.client.metrics.histogram.buckets.Distributions.java Source code

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Here is the source code for io.prometheus.client.metrics.histogram.buckets.Distributions.java

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/*
 * Copyright 2013 Prometheus Team 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.prometheus.client.metrics.histogram.buckets;

import java.util.List;

import com.google.common.collect.ImmutableList;

/**
 * @author matt.proud@gmail.com (Matt T. Proud)
 */
public class Distributions {
    public static List<Float> equallySizedBucketsFor(final float lower, final float upper, final int count) {
        final ImmutableList.Builder<Float> builder = ImmutableList.builder();

        final float partitionSize = (upper - lower) / count;

        for (int i = 0; i < count; i++) {
            builder.add(lower + ((float) i * partitionSize));
        }

        return builder.build();
    }

    public static List<Float> logarithmicSizedBucketsFor(final float lower, final float upper) {
        final ImmutableList.Builder<Float> builder = ImmutableList.builder();
        final int bucketCount = (int) Math.ceil(Math.log(upper) / Math.log(2));

        for (int i = 0; i < bucketCount; i++) {
            final float j = (float) Math.pow(2, i + 1);
            builder.add(j);
        }

        return builder.build();
    }
}