AbsoluteSamplingSequenceGenerator.java

/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.operator.preprocessing.sampling.sequences;

import com.rapidminer.tools.RandomGenerator;

/**
 * This sampling sequence guarantees that the resulting sequence will contain either 
 * all elements or exactly as much as given as target.
 * 
 * @author Sebastian Land
 */
public class AbsoluteSamplingSequenceGenerator extends SamplingSequenceGenerator {
	private int toCome;
	
	private int toAccept;
	
	public AbsoluteSamplingSequenceGenerator(int source, int target, RandomGenerator random) {
		super(random);
		this.toCome = source;
		this.toAccept = target;
	}
	
	@Override
	public boolean useNext() {			
		boolean accept = (random.nextInt(toCome) + 1) <= toAccept;
		if (accept) {
			toAccept--;
		}
		toCome--;
		return accept;
	}		
}