/*
 *  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.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.preprocessing.AbstractValueProcessing;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.math.container.Range;


/**
 * This operator simply replaces all values by their absolute
 * respective value.
 * 
 * @author Ingo Mierswa, Sebastian Land, Tobias Malbrecht
 */
public class AbsoluteValueFilter extends AbstractValueProcessing {

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

	@Override
	public ExampleSetMetaData applyOnFilteredMetaData(ExampleSetMetaData metaData) {
		for (AttributeMetaData amd: metaData.getAllAttributes()) {
			if (amd.isNumerical() && !amd.isSpecial()) {
				Range range = amd.getValueRange();
				amd.setValueRange(new Range(0, Math.max(Math.abs(range.getLower()), Math.abs(range.getUpper()))), amd.getValueSetRelation());
				amd.getMean().setUnkown();
			}
		}

		return metaData;
	}

	@Override
	public ExampleSet applyOnFiltered(ExampleSet exampleSet) throws OperatorException {		
		for (Example example : exampleSet) {
			for (Attribute attribute : exampleSet.getAttributes()) {
				if (attribute.isNumerical()) {
					double value = example.getValue(attribute);
					value = Math.abs(value);
					example.setValue(attribute, value);
				}
			}
		}		
		return exampleSet;
	}

	@Override
	protected int[] getFilterValueTypes() {
		return new int[] { Ontology.NUMERICAL };
	}
	
	@Override
	public boolean writesIntoExistingData() {
		return true;
	}
}