/*
* Created on Oct 08, 2004
* Created by Alon Rohter
* Copyright (C) 2004, 2005, 2006 Aelitis, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* AELITIS, SAS au capital de 46,603.30 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package com.aelitis.azureus.core.util.average;
/**
* Implements a basic moving average.
*/
public class MovingAverage implements Average {
private final int periods;
private double data[];
private int pos = 0;
private double total;
/**
* Create a new moving average.
*/
public MovingAverage(int periods) {
this.periods = periods;
reset();
}
public void reset(){
pos = 0;
total = 0;
data = new double[periods];
}
/**
* Update average and return average-so-far.
*/
public double update(final double newValue) {
total -= data[pos];
total += newValue;
data[pos] = newValue;
pos++;
if (pos == periods) pos = 0;
return calculateAve();
}
/**
* Return average-so-far.
*/
public double getAverage() { return calculateAve(); }
private double calculateAve() {
if ( pos == 0 ){
// resync (I'd prefer not to do this but just in case)
double sum = 0.0;
for (int i=0; i < periods; i++) {
sum += data[i];
}
total = sum;
}
return total / periods;
}
}