/**
* 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 Exponential
* distribution.
*
* <br><br>Copyright (c) 2003
* <br>Politecnico di Milano - dipartimento di Elettronica e Informazione
* @author Fabrizio Frontera - ffrontera@yahoo.it
* @author Bertoli Marco 10-oct-2005
*
*/
public class ExponentialPar extends AbstractParameter implements Parameter {
private double lambda;
/**
* It creates a new empty exponential parameter that must be set to be used.
*
*/
public ExponentialPar() {
}
/**
* It creates a new exponential parameter using the value provided by the user.
* @param lambda double containing the lambda parameter.
*
* @throws IncorrectDistributionParameterException if the value provided is not greater than zero.
*
*/
public ExponentialPar(double lambda) throws IncorrectDistributionParameterException {
setLambda(lambda);
}
public ExponentialPar(Double wlambda) throws IncorrectDistributionParameterException {
this(wlambda.doubleValue());
}
/**
* It returns the value of the parameter lambda of the exponential distribution.
*
* @return double with lamda
*
*/
public double getLambda() {
return lambda;
}
/**
* it change the value of lambda.
* It allow the user to modify the value of the parameter lamda of the
* exponential distribution and verify if the value is correct that is if it is
* greater than zero.
*
* @param lambda double indicating the new value of the parameter lambda
* @throws IncorrectDistributionParameterException if the provided value is not greater than zero.
*
*/
public void setLambda(double lambda) throws IncorrectDistributionParameterException {
if (lambda > 0) //verify that the parameter lambda is gtz, as required.
{
this.lambda = lambda;
} else {
throw new IncorrectDistributionParameterException("Remember: parameter lambda must be gtz");
}
}
/**
* It controls if the parameter is correct or not.
* For the exponential distribution, the parameter is right if lambda is greater
* than zero.
*
* @return boolean, indicating wether the parameter is correct or not.
*
*/
@Override
public boolean check() {
if (lambda > 0) {
return true;
} else {
return false;
}
}
/**
* Sets mean for a given distribution parameter. This method is required to adjust distributions
* mean values into Load Dependent Service Time Strategy
* @param meanValue new mean value for this distribution
* Author: Bertoli Marco
* @throws IncorrectDistributionParameterException if mean value is invalid for this distribution
*/
@Override
public void setMean(double meanValue) throws IncorrectDistributionParameterException {
if (meanValue <= 0 || Double.isInfinite(meanValue)) {
throw new IncorrectDistributionParameterException("Mean value must be finite and greater than zero");
}
lambda = 1 / meanValue;
}
} // end ExponentialPar