DojiIndicator.java

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2017 Marc de Verdelhan & respective authors (see AUTHORS)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package eu.verdelhan.ta4j.indicators.candles;

import eu.verdelhan.ta4j.Indicator;
import eu.verdelhan.ta4j.Decimal;
import eu.verdelhan.ta4j.TimeSeries;
import eu.verdelhan.ta4j.indicators.CachedIndicator;
import eu.verdelhan.ta4j.indicators.simple.AbsoluteIndicator;
import eu.verdelhan.ta4j.indicators.trackers.SMAIndicator;

/**
 * Doji indicator.
 * <p>
 * A candle/tick is considered Doji if its body height is lower than the average multiplied by a factor.
 * @see http://stockcharts.com/school/doku.php?id=chart_school:chart_analysis:introduction_to_candlesticks#doji
 */
public class DojiIndicator extends CachedIndicator<Boolean> {

    /** Body height */
    private final Indicator<Decimal> bodyHeightInd;
    /** Average body height */
    private final SMAIndicator averageBodyHeightInd;

    private final Decimal factor;
    
    /**
     * Constructor.
     * @param series a time series
     * @param timeFrame the number of ticks used to calculate the average body height
     * @param bodyFactor the factor used when checking if a candle is Doji
     */
    public DojiIndicator(TimeSeries series, int timeFrame, Decimal bodyFactor) {
        super(series);
        bodyHeightInd = new AbsoluteIndicator(new RealBodyIndicator(series));
        averageBodyHeightInd = new SMAIndicator(bodyHeightInd, timeFrame);
        factor = bodyFactor;
    }

    @Override
    protected Boolean calculate(int index) {
        if (index < 1) {
            return bodyHeightInd.getValue(index).isZero();
        }
        
        Decimal averageBodyHeight = averageBodyHeightInd.getValue(index-1);
        Decimal currentBodyHeight = bodyHeightInd.getValue(index);
        
        return currentBodyHeight.isLessThan(averageBodyHeight.multipliedBy(factor));
    }
}