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/*
 * ObjectLab, http://www.objectlab.co.uk/open is sponsoring the ObjectLab Kit.
 *
 * Based in London, we are world leaders in the design and development
 * of bespoke applications for the securities financing markets.
 *
 * Click here to learn more
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 *          / _ \| |__ (_) ___  ___| |_| |    __ _| |__
 *         | | | | '_ \| |/ _ \/ __| __| |   / _` | '_ \
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 *
 *                     www.ObjectLab.co.uk
 *
 * $Id: AbstractDateCalculator.java 309 2010-03-23 21:01:49Z marchy $
 *
 * Copyright 2006 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package net.objectlab.kit.util;

import java.io.Serializable;
import java.math.BigDecimal;

/**
 * @author Benoit
 *
 */
public class WeightedAverage implements Serializable {
    private static final long serialVersionUID = 4687472725716492770L;
    private final Total total = new Total();
    private final Total totalExpanded = new Total();
    private int count = 0;
    private final boolean includeZeros;
    private BigDecimal maximum;
    private BigDecimal minimum;

    public WeightedAverage() {
        this.includeZeros = true;
    }

    public WeightedAverage(final boolean includeZeros) {
        this.includeZeros = includeZeros;
    }

    public BigDecimal getTotal() {
        return total.getTotal();
    }

    private void determineMinMax(final BigDecimal value) {
        if (maximum == null || BigDecimalUtil.compareTo(value, maximum) == 1) {
            maximum = value;
        }
        if (minimum == null || BigDecimalUtil.compareTo(value, minimum) == -1) {
            minimum = value;
        }
    }

    public void add(final BigDecimal value, final BigDecimal weightAsAValue) {
        if (includeZeros || BigDecimalUtil.isNotZero(value)) {
            count++;
            total.add(weightAsAValue);
            totalExpanded.add(BigDecimalUtil.multiply(value, weightAsAValue));
            determineMinMax(value);
        }
    }

    public BigDecimal getMaximum() {
        return maximum;
    }

    public BigDecimal getMinimum() {
        return minimum;
    }

    public BigDecimal getWeightedAverage() {
        return BigDecimalUtil.divide(totalExpanded.getTotal(), total.getTotal(), BigDecimal.ROUND_HALF_UP);
    }

    public int getCount() {
        return count;
    }
}