/*
 *  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.features.construction;

import java.util.LinkedList;
import java.util.List;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.set.AttributeWeightedExampleSet;
import com.rapidminer.generator.ConstantGenerator;
import com.rapidminer.generator.FeatureGenerator;
import com.rapidminer.tools.RandomGenerator;


/**
 * This PopulationOperator generates new random constant attribute in an
 * individual's example table.
 * 
 * @author Ingo Mierswa
 *          Exp $
 */
public class ConstantGeneration extends ExampleSetBasedIndividualOperator {

	/** The probability for generating new constants. */
	private double prob;

    private RandomGenerator random;
    
    
	/** Creates a new constant generator. */
	public ConstantGeneration(double prob, RandomGenerator random) {
		this.prob = prob;
        this.random = random;
	}

	@Override
	public List<ExampleSetBasedIndividual> operate(ExampleSetBasedIndividual individual) throws Exception {
		AttributeWeightedExampleSet exampleSet = individual.getExampleSet();
		if (random.nextDouble() < prob) {
			FeatureGenerator generator = new ConstantGenerator(random.nextDoubleInRange(-10.0d, 10.0d));
			List<FeatureGenerator> generatorList = new LinkedList<FeatureGenerator>();
			generatorList.add(generator);
			List<Attribute> newAttributes = FeatureGenerator.generateAll(exampleSet.getExampleTable(), generatorList);
			for (Attribute newAttribute : newAttributes)
				exampleSet.getAttributes().addRegular(newAttribute);
		}
		List<ExampleSetBasedIndividual> result = new LinkedList<ExampleSetBasedIndividual>();
		result.add(new ExampleSetBasedIndividual(exampleSet));
		return result;
	}
}