/*
 *  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.transformation.aggregation;

import java.util.HashSet;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.table.DataRow;

/**
 * This is an {@link Aggregator} for the {@link CountAggregationFunction}
 * It counts all non-NaN values.
 * 
 * @author Sebastian Land
 */
public class CountAggregator implements Aggregator {

    private Attribute sourceAttribute;
    private double count = 0;
    private boolean isIgnoringMissings = false;

    private boolean isCountingOnlyDistinct = false;
    private HashSet<Double> valuesOccured = null;

    public CountAggregator(AggregationFunction function) {
        this.sourceAttribute = function.getSourceAttribute();
        this.isIgnoringMissings = function.isIgnoringMissings();
        this.isCountingOnlyDistinct = function.isCountingOnlyDistinct();
        if (isCountingOnlyDistinct)
            valuesOccured = new HashSet<Double>();
    }

    @Override
    public void count(Example example) {
        double value = example.getValue(sourceAttribute);
        if (!Double.isNaN(value)) {
            if (!isCountingOnlyDistinct || valuesOccured.add(value))
                count++;
        } else if (!isIgnoringMissings) {
            count = Double.NaN;
        }
    }

    @Override
    public void count(Example example, double weight) {
        double value = example.getValue(sourceAttribute);
        if (!Double.isNaN(value)) {
            if (!isCountingOnlyDistinct || valuesOccured.add(value))
                count+= weight;
        } else if (!isIgnoringMissings) {
            count = Double.NaN;
        }
    }


    @Override
    public void set(Attribute attribute, DataRow row) {
        row.set(attribute, count);
    }
}