/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 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;

import java.util.Iterator;
import java.util.List;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.DoubleArrayDataRow;
import com.rapidminer.example.table.MemoryExampleTable;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;


/** <p>Build the cartesian product of two example sets. In contrast to the {@link ExampleSetJoin}
 *  operator, this operator does not depend on Id attributes. The result example set will
 *  consist of the union set or the union list (depending on parameter
 *  setting double attributes will be removed or renamed) of both feature sets. In case of removing 
 *  double attribute the attribute values must be the same for the examples of both example set, otherwise
 *  an exception will be thrown.</p>
 * 
 *  <p>Please note that this check for double attributes will only be applied for regular attributes. 
 *  Special attributes of the second input example set which do not exist in the first example set will
 *  simply be added. If they already exist they are simply skipped.</p>
 *  
 * @author Peter B. Volk
 * @version $Id: ExampleSetCartesian.java,v 1.3 2008/05/09 19:22:54 ingomierswa Exp $
 */
public class ExampleSetCartesian extends AbstractExampleSetJoin {

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

    /**
     * Joins the data WITHOUT a WHERE criteria. 
     * @param es1
     * @param es2
     * @param originalAttributeSources
     * @param unionAttributeList
     * @return the table with the joined data
     * @throws OperatorException
     */
    protected MemoryExampleTable joinData(ExampleSet es1, ExampleSet es2, List<AttributeSource> originalAttributeSources, List<Attribute> unionAttributeList) throws OperatorException {
        MemoryExampleTable unionTable = new MemoryExampleTable(unionAttributeList);
        Iterator<Example> reader = es1.iterator();
        while (reader.hasNext()) {
            Example example1 = reader.next();
            Iterator reader2 = es2.iterator();
            while (reader2.hasNext()) {
                Example example2 = (Example) reader2.next();
                double[] unionDataRow = new double[unionAttributeList.size()];
                Iterator<AttributeSource> a = originalAttributeSources.iterator();
                int index = 0;
                while (a.hasNext()) {
                    AttributeSource source = a.next();
                    if (source.getSource() == AttributeSource.FIRST_SOURCE) {
                        unionDataRow[index] = example1.getValue(source.getAttribute());
                    } else if (source.getSource() == AttributeSource.SECOND_SOURCE) {
                        unionDataRow[index] = example2.getValue(source.getAttribute());
                    }
                    index++;
                }

                unionTable.addDataRow(new DoubleArrayDataRow(unionDataRow));
                checkForStop();
            }
        }

        return unionTable;
    }

    protected boolean isIdNeeded() {
        return false;
    }
}