Zipf.java

/*******************************************************************************
 * gMix open source project - https://svs.informatik.uni-hamburg.de/gmix/
 * Copyright (C) 2014  SVS
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package staticContent.evaluation.loadGenerator.randomVariable;

import org.apache.commons.math.MathException;

public class Zipf extends RandomVariable {

	private final String errorMessage =
			"invalid syntax for random variable "
			+this.getClass().getName()
			+"; distribution variable must be in the following form: "
			+"[RAND_VAR:Zipf(int numberOfElements, double exponent)]";
	
	private final int numberOfParameters = 2;
	private final int numberOfElements;
	private final double exponent;
	
	
	public Zipf(String[] parameters) {
		super(parameters);
		if (parameters.length != numberOfParameters)
			throw new RuntimeException(errorMessage); 
		try {
			this.numberOfElements = Integer.parseInt(parameters[0]); 
			this.exponent = Double.parseDouble(parameters[1]); 
			// test:
			this.randomDataImpl.nextZipf(numberOfElements, exponent);
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(errorMessage); 
		}
	}
	

	@Override
	public int drawIntSample() {
		try {
			return randomDataImpl.nextZipf(numberOfElements, exponent);
		} catch (MathException e) {
			e.printStackTrace();
			throw new RuntimeException(errorMessage); 
		}
	}

}