/*
 *  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.datatable;

import java.util.Iterator;

import com.rapidminer.operator.visualization.dependencies.NumericalMatrix;


/**
 *  This iterator iterates over examples of a numerical matrix and creates
 *  {@link com.rapidminer.datatable.CorrelationMatrixRow2DataTableRowWrapper} objects.
 *  If matrix is symetrical, it will iterate only over the pairs of the lower left triangle of the matrix,
 *  sparing the diagonal. Otherwise it will return all pairs.
 * 
 *   @author Ingo Mierswa, Sebastian Land
 */
public class PairwiseMatrix2DataTableRowIterator implements Iterator<DataTableRow> {

    private NumericalMatrix matrix;

    private int firstAttribute;

    private int secondAttribute;

    private boolean showSymetrically;

    /** Creates a new DataTable iterator for the given numerical matrix. If the idAttribute is null the DataTableRows
     *  will not be able to deliver an Id. */
    public PairwiseMatrix2DataTableRowIterator(NumericalMatrix matrix) {
        this(matrix, true);
    }

    /**
     * Creates a new iterator that will show the matrix symetrically only if matrix is symetrically
     * and parameter showSymetrically is true.
     */
    public PairwiseMatrix2DataTableRowIterator(NumericalMatrix matrix, boolean showSymetrically) {
        this.showSymetrically = showSymetrically;
        this.matrix = matrix;
        this.firstAttribute = 0;
        if (matrix.isSymmetrical())
            this.secondAttribute = 1;
        else
            this.secondAttribute = 0;
    }

    @Override
    public boolean hasNext() {
        return (firstAttribute < matrix.getNumberOfRows()) && (secondAttribute < matrix.getNumberOfColumns());
    }

    @Override
    public DataTableRow next() {
        DataTableRow row = new PairwiseMatrix2DataTableRowWrapper(matrix, firstAttribute, secondAttribute);
        if (matrix.isSymmetrical() && showSymetrically) {
            secondAttribute++;
            if (secondAttribute >= matrix.getNumberOfColumns()) {
                firstAttribute++;
                secondAttribute = firstAttribute + 1;
            }
        } else {
            secondAttribute++;
            if (secondAttribute >= matrix.getNumberOfColumns()) {
                secondAttribute = 0;
                firstAttribute++;
            }
        }
        return row;
    }

    @Override
    public void remove() {
        throw new RuntimeException("PairwiseCorrelation2DataTableRowIterator: removing rows is not supported!");
    }
}