/*
 *  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.generator;

import com.rapidminer.tools.LogService;

/**
 * This class is a very simple implementation of a FeatureGenerator. It has two
 * numerical input attributes and one output attribute. Depending on the mode
 * specified in the constructor the result will be the sum, difference, product
 * or quotient. The four modes are numered from 0 to 3 int this order.
 * 
 * @author Simon Fischer, Ingo Mierswa
 * @version $Id: BasicArithmeticOperationGenerator.java,v 2.15 2006/03/21
 *          15:35:40 ingomierswa Exp $
 */
public class BasicArithmeticOperationGenerator extends BinaryNumericalGenerator {

	public static final int SUM = 0;

	public static final int DIFFERENCE = 1;

	public static final int PRODUCT = 2;

	public static final int QUOTIENT = 3;

	private static final String[] FUNCTION_NAMES = { "+", "-", "*", "/" };

	private int mode;

	public BasicArithmeticOperationGenerator(int mode) {
		this.mode = mode;
	}

	public BasicArithmeticOperationGenerator() {}

	public boolean isSelfApplicable() {
		return mode == PRODUCT;
	}

	public boolean isCommutative() {
		return ((mode == PRODUCT) || (mode == SUM));
	}

	public FeatureGenerator newInstance() {
		return new BasicArithmeticOperationGenerator(mode);
	}

	public double calculateValue(double o1, double o2) {
		double r = 0.0d;
		switch (mode) {
			case SUM:
				r = o1 + o2;
				break;
			case DIFFERENCE:
				r = o1 - o2;
				break;
			case PRODUCT:
				r = o1 * o2;
				break;
			case QUOTIENT:
				r = o1 / o2;
				break;
		}
		return r;
	}

	public void setFunction(String name) {
		for (int i = 0; i < FUNCTION_NAMES.length; i++) {
			if (FUNCTION_NAMES[i].equals(name)) {
				this.mode = i;
				return;
			}
		}
		LogService.getGlobal().log("Illegal function name '" + name + "' for " + getClass().getName() + ".", LogService.ERROR);
	}

	public String getFunction() {
		return FUNCTION_NAMES[mode];
	}

	public boolean equals(Object o) {
		return (super.equals(o) && (this.mode == ((BasicArithmeticOperationGenerator) o).mode));
	}
	
	public int hashCode() {
		return super.hashCode() ^ Integer.valueOf(mode).hashCode();
	}
}