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* Copyright 2010-2013 Coda Hale and Yammer, Inc., 2014-2015 Dropwizard Team
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package org.glassfish.jersey.server.internal.monitoring;
import java.util.Arrays;
import java.util.Collection;
import java.util.concurrent.TimeUnit;
import static java.lang.Math.floor;
/**
* A statistical snapshot of a {@link UniformTimeValuesSnapshot}.
*
* @author Stepan Vavra (stepan.vavra at oracle.com)
* @author Dropwizard Team
* @see <a href="https://github.com/dropwizard/metrics">https://github.com/dropwizard/metrics</a>
*/
class UniformTimeValuesSnapshot extends AbstractTimeSnapshot {
private final long[] values;
/**
* Create a new snapshot with the given values.
*
* @param values an unordered set of values in the reservoir
* @param timeInterval The time interval this snapshot relates to
* @param timeIntervalUnit The time unit of the time interval
*/
public UniformTimeValuesSnapshot(Collection<Long> values, final long timeInterval, final TimeUnit timeIntervalUnit) {
super(timeInterval, timeIntervalUnit);
final Object[] copy = values.toArray();
this.values = new long[copy.length];
for (int i = 0; i < copy.length; i++) {
this.values[i] = (Long) copy[i];
}
Arrays.sort(this.values);
}
/**
* Returns the value at the given quantile.
*
* @param quantile a given quantile, in {@code [0..1]}
* @return the value in the distribution at {@code quantile}
*/
public double getValue(double quantile) {
if (quantile < 0.0 || quantile > 1.0 || Double.isNaN(quantile)) {
throw new IllegalArgumentException(quantile + " is not in [0..1] range");
}
if (values.length == 0) {
return 0.0;
}
final double pos = quantile * (values.length + 1);
final int index = (int) pos;
if (index < 1) {
return values[0];
}
if (index >= values.length) {
return values[values.length - 1];
}
final double lower = values[index - 1];
final double upper = values[index];
return lower + (pos - floor(pos)) * (upper - lower);
}
/**
* Returns the number of values in the snapshot.
*
* @return the number of values
*/
@Override
public long size() {
return values.length;
}
/**
* Returns the entire set of values in the snapshot.
*
* @return the entire set of values
*/
public long[] getValues() {
return Arrays.copyOf(values, values.length);
}
/**
* Returns the highest value in the snapshot.
*
* @return the highest value
*/
@Override
public long getMax() {
if (values.length == 0) {
return 0;
}
return values[values.length - 1];
}
/**
* Returns the lowest value in the snapshot.
*
* @return the lowest value
*/
@Override
public long getMin() {
if (values.length == 0) {
return 0;
}
return values[0];
}
/**
* Returns the arithmetic mean of the values in the snapshot.
*
* @return the arithmetic mean
*/
@Override
public double getMean() {
if (values.length == 0) {
return 0;
}
double sum = 0;
for (long value : values) {
sum += value;
}
return sum / values.length;
}
}