/*
* Copyright (c) 2013-2014, Parallel Universe Software Co. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 3.0
* as published by the Free Software Foundation.
*/
package co.paralleluniverse.common.monitoring;
import com.codahale.metrics.Reservoir;
import com.codahale.metrics.Snapshot;
import java.util.concurrent.atomic.LongAccumulator;
import java.util.concurrent.atomic.LongAdder;
/**
* This is a false reservoir that merely records the precise max and min, as well as an approximate mean.
*
* @author pron
*/
public class SimpleReservoir implements Reservoir {
private final LongAdder num = new LongAdder();
private final LongAdder sum = new LongAdder();
private final LongAccumulator max = new LongAccumulator(Math::max, 0);
private final LongAccumulator min = new LongAccumulator(Math::min, Long.MAX_VALUE);
@Override
public int size() {
return 0;
}
@Override
public void update(long value) {
num.increment();
sum.add(value);
max.accumulate(value);
min.accumulate(value);
}
@Override
public Snapshot getSnapshot() {
return new Snapshot(new long[0]) {
private final long num = SimpleReservoir.this.num.sumThenReset();
private final long sum = SimpleReservoir.this.sum.sumThenReset();
private final long max = SimpleReservoir.this.max.getThenReset();
private final long min = SimpleReservoir.this.min.getThenReset();
@Override
public int size() {
return 0;
}
@Override
public long getMax() {
return max;
}
@Override
public long getMin() {
return min;
}
@Override
public double getMean() {
return (double) sum / (double) num;
}
};
}
}