/*
 *  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.example;

import com.rapidminer.tools.math.Averagable;

/**
 * Helper class containing the name of an attribute and the corresponding
 * weight.
 * 
 * @author Ingo Mierswa
 * @version $Id: AttributeWeight.java,v 1.4 2008/05/09 19:22:42 ingomierswa Exp $
 */
public class AttributeWeight extends Averagable implements Comparable<AttributeWeight> {

	private static final long serialVersionUID = 4459877599722270416L;

	/** The name of the attribute. */
	private String name;

	/** The weight of the attribute. */
	private double weight;

    /** A counter for building averages. */
    private int counter = 1;
    
	/** The parent attribute weights. */
	private AttributeWeights weights;

	/** Creates a new attribute weight object. */
	public AttributeWeight(AttributeWeights weights, String name, double weight) {
		this.weights = weights;
		this.name = name;
		this.weight = weight;
	}

	/** Clone constructor. The name and the weight are deep cloned, the reference to
     *  the AttributeWeights object is only a shallow copy. */
	public AttributeWeight(AttributeWeight attWeight) {
		super(attWeight);
		this.weights = attWeight.weights;
		this.name = attWeight.name;
		this.weight = attWeight.weight;
	}

	/** Returns the name of the attribute. */
	public String getName() {
		return name;
	}

	/** Returns the weight of the attribute. */
	public double getWeight() {
		return weight / counter;
	}

	/** Sets the weight of the attribute. */
	public void setWeight(double weight) {
		this.weight = weight;
	}

	/**
	 * Returns the MakroVariance since no other micro variance can be
	 * calculated.
	 */
	public double getMikroVariance() {
		return getMakroVariance();
	}

	/** Returns the current weight. */
	public double getMikroAverage() {
		return getWeight() / counter;
	}

	/**
	 * Compares the weight of this object with the weight of another
	 * AttributeWeight object. May also use the absolute weight.
	 */
	public int compareTo(AttributeWeight o) {
		double w1 = weight;
		double w2 = o.weight;

		assert(weights == o.weights);
		if (weights.getWeightType() == AttributeWeights.ABSOLUTE_WEIGHTS) {
			w1 = Math.abs(w1);
			w2 = Math.abs(w2);
		}

		return Double.compare(w1, w2) * weights.getSortingType();
	}

	/** Returns true if both objects have the same name and the same weight. */
	public boolean equals(Object o) {
		if (!(o instanceof AttributeWeight))
			return false;
		AttributeWeight w = (AttributeWeight)o;
		return this.name.equals(w.name) && (this.weight == w.weight);
	}

	public int hashCode() {
		long	bits = Double.doubleToLongBits(this.weight);
		return this.name.hashCode() ^ ((int)(bits ^ bits >>> 32));
	}

	/** Builds the sum of weights and counters. */
	public void buildSingleAverage(Averagable avg) {
		AttributeWeight other = (AttributeWeight) avg;
		this.weight += other.weight;
        this.counter += other.counter;
	}
}