com.github.tomakehurst.wiremock.http.LogNormal Maven / Gradle / Ivy
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/*
* Copyright (C) 2015-2021 Thomas Akehurst
*
* 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.github.tomakehurst.wiremock.http;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.concurrent.ThreadLocalRandom;
/**
* Returns log normally distributed values. Takes two parameters, the median (50th percentile) of
* the lognormal and the standard deviation of the underlying normal distribution.
*
* The larger the standard deviation the longer the tails.
*
* @see lognormal
* example
*/
public final class LogNormal implements DelayDistribution {
@JsonProperty("median")
private final double median;
@JsonProperty("sigma")
private final double sigma;
/**
* @param median 50th percentile of the distribution in millis
* @param sigma standard deviation of the distribution, a larger value produces a longer tail
*/
@JsonCreator
public LogNormal(@JsonProperty("median") double median, @JsonProperty("sigma") double sigma) {
this.median = median;
this.sigma = sigma;
}
@Override
public long sampleMillis() {
return Math.round(Math.exp(ThreadLocalRandom.current().nextGaussian() * sigma) * median);
}
}