/*
 *  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.filter;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.annotation.ResourceConsumptionEstimator;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.OperatorResourceConsumptionHandler;

/**
 * Converts all string attributes to nominal attributes. Each string value is simply
 * used as nominal value of the new attribute. If the value is missing, the new value 
 * will be missing.
 * 
 * @author Ingo Mierswa
 */
public class String2Nominal extends AbstractFilteredDataProcessing {

	public String2Nominal(OperatorDescription description) {
		super(description);
	}

	@Override
	public ExampleSet applyOnFiltered(ExampleSet exampleSet) throws OperatorException {
		for (Attribute attribute : exampleSet.getAttributes()) {
			if (attribute.isNominal()) {
				Attribute newAttribute = AttributeFactory.changeValueType(attribute, Ontology.NOMINAL);
				exampleSet.getAttributes().replace(attribute, newAttribute);
			}
		}

		return exampleSet;
	}

	@Override
	public ExampleSetMetaData applyOnFilteredMetaData(ExampleSetMetaData emd) {
		for (AttributeMetaData amd : emd.getAllAttributes()) {
			if (amd.isNominal()) {
				amd.setType(Ontology.NOMINAL);
			}
		}
		return emd;
	}
	
	@Override
	protected int[] getFilterValueTypes() {
		return new int[] { Ontology.STRING };
	}
	
	@Override
	public boolean writesIntoExistingData() {
		return false;
	}
	
	@Override
	public ResourceConsumptionEstimator getResourceConsumptionEstimator() {
		return OperatorResourceConsumptionHandler.getResourceConsumptionEstimator(getInputPort(), String2Nominal.class, null);
	}
}