/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
/***************************************************************************************
* Attribution Notice
*
* This file is imported from Metrics (https://github.com/codahale/metrics subproject metrics-core).
* Metrics is Copyright (c) 2010-2012 Coda Hale, Yammer.com
* Metrics is Published under Apache Software License 2.0, see LICENSE in root folder.
*
* Thank you for the Metrics developers efforts in making their library available under an Apache license.
* EsperTech incorporates Metrics version 0.2.2 in source code form since Metrics depends on SLF4J
* and this dependency is not possible to introduce for Esper.
* *************************************************************************************
*/
package com.espertech.esper.metrics.codahale_metrics.metrics.util;
import com.espertech.esper.metrics.codahale_metrics.metrics.core.Gauge;
import static java.lang.Double.isInfinite;
import static java.lang.Double.isNaN;
/**
* A gauge which measures the ratio of one value to another.
* If the denominator is zero, not a number, or infinite, the resulting ratio is not a number.
*/
public abstract class RatioGauge extends Gauge<Double> {
/**
* Returns the numerator (the value on the top half of the fraction or the left-hand side of the
* ratio).
*
* @return the numerator
*/
protected abstract double getNumerator();
/**
* Returns the denominator (the value on the bottom half of the fraction or the right-hand side
* of the ratio).
*
* @return the denominator
*/
protected abstract double getDenominator();
@Override
public Double value() {
final double d = getDenominator();
if (isNaN(d) || isInfinite(d) || d == 0.0) {
return Double.NaN;
}
return getNumerator() / d;
}
}