/**
* Copyright (C) 2006, Laboratorio di Valutazione delle Prestazioni - Politecnico di Milano
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package jmt.engine.random;
import jmt.common.exception.IncorrectDistributionParameterException;
/**
*
* This is the parameter that should be passed to the Poisson
* distribution.
*
* <br><br>Copyright (c) 2003
* <br>Politecnico di Milano - dipartimento di Elettronica e Informazione
* @author Fabrizio Frontera - ffrontera@yahoo.it
*
*/
public class PoissonPar extends AbstractParameter implements Parameter {
private double mean;
/**
* It creates a new poisson parameter with the mean required by the user. It also
* verify that the required mean is correct (mean must be greater than zero).
*
* @param mean double containing the mean of the distribution (also called lambda).
*
* @throws IncorrectDistributionParameterException if mean is not greater than zero.
*
*/
public PoissonPar(double mean) throws IncorrectDistributionParameterException {
if (mean <= 0) {
throw new IncorrectDistributionParameterException("mean must be gtz");
} else {
this.mean = mean;
}
}
public PoissonPar(Double wmean) throws IncorrectDistributionParameterException {
this(wmean.doubleValue());
}
/**
* It verify that the parameter is correct. For the poisson distribution the
* parameter is correct if the mean is greater than zero.
*
* @return boolean, indicating wether the parameter is correct or not.
*
*/
@Override
public boolean check() {
if (mean <= 0) {
return false;
} else {
return true;
}
}
/**
* it returns the mean of the distribution.
* It return the value of the mean of the poisson distribution (also calleda
* lambda in the definition).
*
* @return double with the value of the mean of the poisson distribution.
*
*/
public double getMean() {
return mean;
}
/**
* it change the mean of the distribution.
* It allow the user to change the mean of the poisson distribution and it
* verify that the new value is correct (the mean must be greater than zero).
*
* @param mean double indicating the new value of the parameter mean (or lambda).
* @throws IncorrectDistributionParameterException if the provided value is not greater than zero.
*
*/
@Override
public void setMean(double mean) throws IncorrectDistributionParameterException {
if (mean <= 0) {
throw new IncorrectDistributionParameterException("mean must be gtz");
} else {
this.mean = mean;
}
}
} // end PoissonPar