How to remove outliers(small circle) from Box and Whisker chart in jfreechart

Question

Im using below code to generate box plot chart. But depend on some values it show small circle without drawing the whisker. I need to show whisker not the small circle. Is it possible to hide circle and show the whisker?

private void createBoxPlotChart(OutputStream out, Object data)
            throws Exception {

        ChartRenderingInfo info = new ChartRenderingInfo();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] ptsImageBytes = null;

        DefaultBoxAndWhiskerCategoryDataset boxAndWhiskerCategoryDS = createBoxAndWhiskerCategoryDataSet();

        JFreeChart chart = ChartFactory.createBoxAndWhiskerChart(selectedFlight
                + " - Time on Hold", "Arrival Time (Days)",
                "Hold Time (Mins)", boxAndWhiskerCategoryDS, true); 


        NumberAxis rangeAxis = (NumberAxis) chart.getCategoryPlot()
                .getRangeAxis();
        rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());        
        rangeAxis.setAutoRangeIncludesZero(true);


        CategoryAxis domainAxis = chart.getCategoryPlot().getDomainAxis();

        BoxAndWhiskerRenderer renderer = (BoxAndWhiskerRenderer) chart.getCategoryPlot().getRenderer();
        //renderer.setFillBox(false);        
        renderer.setMeanVisible(false);
        renderer.setUseOutlinePaintForWhiskers(false);  
        renderer.setMedianVisible(false);             


        if(boxAndWhiskerCategoryDS.getRowCount()>8){
            domainAxis.setCategoryLabelPositions(CategoryLabelPositions
                    .createUpRotationLabelPositions(Math.PI / 5.0));
        }       

        chart.getCategoryPlot().setBackgroundPaint(Color.white);
        chart.getCategoryPlot().setDomainGridlinePaint(Color.gray);
        chart.getCategoryPlot().setRangeGridlinePaint(Color.gray);
        chart.getCategoryPlot().setOutlineVisible(false);

        BufferedImage pageImage = chart.createBufferedImage(CHART_WIDTH,
                CHART_HEIGHT, BufferedImage.TYPE_INT_BGR, info);
        ImageIO.write(pageImage, IMAGE_TYPE, baos);
        baos.flush();
        if (null != baos) {
            ptsImageBytes = baos.toByteArray();
        }

        ImageIO.write(pageImage, IMAGE_TYPE, out);

    }

    private DefaultBoxAndWhiskerCategoryDataset createBoxAndWhiskerCategoryDataSet()
            throws ParseException {     


        DefaultBoxAndWhiskerCategoryDataset dataset = new DefaultBoxAndWhiskerCategoryDataset();

        for (String graph : graphList) {            

            final List<Double> list = new ArrayList<Double>();
            for (ereportDto ereportDto : holdTimeRptList) {
                if (ereportDto != null && ereportDto.getHoldTime() != 0
                        && ereportDto.getGraphTime() != null
                        && ereportDto.getGraphTime().equalsIgnoreCase(graph)) {                 

                    double medianVal=ereportDto.getGraphHoldEntry()+((ereportDto.getGraphHoldExit()-ereportDto.getGraphHoldEntry())/2);

                    list.add(new Double(ereportDto.getGraphTimeAt120NM()));                             
                    list.add(new Double(ereportDto.getGraphHoldEntry()));
                    list.add(new Double(medianVal));                    
                    list.add(new Double(ereportDto.getGraphHoldExit()));                    
                    list.add(new Double(ereportDto.getGraphLandedTime()));              

                }
            }
            dataset.add(list, graph, graph);
        }



        return dataset;

    }

Answer 1

Made a custom extension to be able to set the radius of outliers. Set it to 0 and they are gone.

package de.vontrostorff.kivsproject.util;

import lombok.Getter;
import lombok.Setter;
import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.renderer.Outlier;
import org.jfree.chart.renderer.OutlierList;
import org.jfree.chart.renderer.OutlierListCollection;
import org.jfree.chart.renderer.category.BoxAndWhiskerRenderer;
import org.jfree.chart.renderer.category.CategoryItemRendererState;
import org.jfree.chart.ui.RectangleEdge;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.statistics.BoxAndWhiskerCategoryDataset;

import java.awt.*;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

public class CustomBoxAndWhiskerRenderer extends BoxAndWhiskerRenderer {

    private Double outlierRadius;

    public Double getOutlierRadius() {
        return outlierRadius;
    }

    public void setOutlierRadius(Double outlierRadius) {
        this.outlierRadius = outlierRadius;
    }

    @Override
    public void drawVerticalItem(Graphics2D g2, CategoryItemRendererState state,
                                 Rectangle2D dataArea, CategoryPlot plot, CategoryAxis domainAxis,
                                 ValueAxis rangeAxis, CategoryDataset dataset, int row, int column) {

        BoxAndWhiskerCategoryDataset bawDataset
                = (BoxAndWhiskerCategoryDataset) dataset;

        double categoryEnd = domainAxis.getCategoryEnd(column,
                getColumnCount(), dataArea, plot.getDomainAxisEdge());
        double categoryStart = domainAxis.getCategoryStart(column,
                getColumnCount(), dataArea, plot.getDomainAxisEdge());
        double categoryWidth = categoryEnd - categoryStart;

        double xx = categoryStart;
        int seriesCount = getRowCount();
        int categoryCount = getColumnCount();

        if (seriesCount > 1) {
            double seriesGap = dataArea.getWidth() * getItemMargin()
                    / (categoryCount * (seriesCount - 1));
            double usedWidth = (state.getBarWidth() * seriesCount)
                    + (seriesGap * (seriesCount - 1));
            // offset the start of the boxes if the total width used is smaller
            // than the category width
            double offset = (categoryWidth - usedWidth) / 2;
            xx = xx + offset + (row * (state.getBarWidth() + seriesGap));
        }
        else {
            // offset the start of the box if the box width is smaller than the
            // category width
            double offset = (categoryWidth - state.getBarWidth()) / 2;
            xx = xx + offset;
        }

        double yyAverage;
        double yyOutlier;

        Paint itemPaint = getItemPaint(row, column);
        g2.setPaint(itemPaint);
        Stroke s = getItemStroke(row, column);
        g2.setStroke(s);

        double aRadius = 0;                 // average radius

        RectangleEdge location = plot.getRangeAxisEdge();

        Number yQ1 = bawDataset.getQ1Value(row, column);
        Number yQ3 = bawDataset.getQ3Value(row, column);
        Number yMax = bawDataset.getMaxRegularValue(row, column);
        Number yMin = bawDataset.getMinRegularValue(row, column);
        Shape box = null;
        if (yQ1 != null && yQ3 != null && yMax != null && yMin != null) {

            double yyQ1 = rangeAxis.valueToJava2D(yQ1.doubleValue(), dataArea,
                    location);
            double yyQ3 = rangeAxis.valueToJava2D(yQ3.doubleValue(), dataArea,
                    location);
            double yyMax = rangeAxis.valueToJava2D(yMax.doubleValue(),
                    dataArea, location);
            double yyMin = rangeAxis.valueToJava2D(yMin.doubleValue(),
                    dataArea, location);
            double xxmid = xx + state.getBarWidth() / 2.0;
            double halfW = (state.getBarWidth() / 2.0) * getWhiskerWidth();

            // draw the body...
            box = new Rectangle2D.Double(xx, Math.min(yyQ1, yyQ3),
                    state.getBarWidth(), Math.abs(yyQ1 - yyQ3));
            if (getFillBox()) {
                g2.fill(box);
            }

            Paint outlinePaint = getItemOutlinePaint(row, column);
            if (getUseOutlinePaintForWhiskers()) {
                g2.setPaint(outlinePaint);
            }
            // draw the upper shadow...
            g2.draw(new Line2D.Double(xxmid, yyMax, xxmid, yyQ3));
            g2.draw(new Line2D.Double(xxmid - halfW, yyMax, xxmid + halfW, yyMax));

            // draw the lower shadow...
            g2.draw(new Line2D.Double(xxmid, yyMin, xxmid, yyQ1));
            g2.draw(new Line2D.Double(xxmid - halfW, yyMin, xxmid + halfW, yyMin));

            g2.setStroke(getItemOutlineStroke(row, column));
            g2.setPaint(outlinePaint);
            g2.draw(box);
        }

        g2.setPaint(getArtifactPaint());

        // draw mean - SPECIAL AIMS REQUIREMENT...
        if (isMeanVisible()) {
            Number yMean = bawDataset.getMeanValue(row, column);
            if (yMean != null) {
                yyAverage = rangeAxis.valueToJava2D(yMean.doubleValue(),
                        dataArea, location);
                aRadius = state.getBarWidth() / 4;
                // here we check that the average marker will in fact be
                // visible before drawing it...
                if ((yyAverage > (dataArea.getMinY() - aRadius))
                        && (yyAverage < (dataArea.getMaxY() + aRadius))) {
                    Ellipse2D.Double avgEllipse = new Ellipse2D.Double(
                            xx + aRadius, yyAverage - aRadius, aRadius * 2,
                            aRadius * 2);
                    g2.fill(avgEllipse);
                    g2.draw(avgEllipse);
                }
            }
        }

        // draw median...
        if (isMedianVisible()) {
            Number yMedian = bawDataset.getMedianValue(row, column);
            if (yMedian != null) {
                double yyMedian = rangeAxis.valueToJava2D(
                        yMedian.doubleValue(), dataArea, location);
                g2.draw(new Line2D.Double(xx, yyMedian,
                        xx + state.getBarWidth(), yyMedian));
            }
        }

        // draw yOutliers...
        double maxAxisValue = rangeAxis.valueToJava2D(
                rangeAxis.getUpperBound(), dataArea, location) + aRadius;
        double minAxisValue = rangeAxis.valueToJava2D(
                rangeAxis.getLowerBound(), dataArea, location) - aRadius;

        g2.setPaint(itemPaint);

        // draw outliers
        double oRadius = outlierRadius == null? state.getBarWidth()/3: outlierRadius;    // outlier radius
        java.util.List outliers = new ArrayList();
        OutlierListCollection outlierListCollection
                = new OutlierListCollection();

        // From outlier array sort out which are outliers and put these into a
        // list If there are any farouts, set the flag on the
        // OutlierListCollection
        List yOutliers = bawDataset.getOutliers(row, column);
        if (yOutliers != null) {
            for (int i = 0; i < yOutliers.size(); i++) {
                double outlier = ((Number) yOutliers.get(i)).doubleValue();
                Number minOutlier = bawDataset.getMinOutlier(row, column);
                Number maxOutlier = bawDataset.getMaxOutlier(row, column);
                Number minRegular = bawDataset.getMinRegularValue(row, column);
                Number maxRegular = bawDataset.getMaxRegularValue(row, column);
                if (outlier > maxOutlier.doubleValue()) {
                    outlierListCollection.setHighFarOut(true);
                }
                else if (outlier < minOutlier.doubleValue()) {
                    outlierListCollection.setLowFarOut(true);
                }
                else if (outlier > maxRegular.doubleValue()) {
                    yyOutlier = rangeAxis.valueToJava2D(outlier, dataArea,
                            location);
                    outliers.add(new Outlier(xx + state.getBarWidth() / 2.0,
                            yyOutlier, oRadius));
                }
                else if (outlier < minRegular.doubleValue()) {
                    yyOutlier = rangeAxis.valueToJava2D(outlier, dataArea,
                            location);
                    outliers.add(new Outlier(xx + state.getBarWidth() / 2.0,
                            yyOutlier, oRadius));
                }
                Collections.sort(outliers);
            }

            // Process outliers. Each outlier is either added to the
            // appropriate outlier list or a new outlier list is made
            for (Iterator iterator = outliers.iterator(); iterator.hasNext();) {
                Outlier outlier = (Outlier) iterator.next();
                outlierListCollection.add(outlier);
            }

            for (Iterator iterator = outlierListCollection.iterator();
                 iterator.hasNext();) {
                OutlierList list = (OutlierList) iterator.next();
                Outlier outlier = list.getAveragedOutlier();
                Point2D point = outlier.getPoint();

                if (list.isMultiple()) {
                    drawMultipleEllipse(point, state.getBarWidth(), oRadius,
                            g2);
                }
                else {
                    drawEllipse(point, oRadius, g2);
                }
            }

            // draw farout indicators
            if (outlierListCollection.isHighFarOut()) {
                drawHighFarOut(aRadius / 2.0, g2,
                        xx + state.getBarWidth() / 2.0, maxAxisValue);
            }

            if (outlierListCollection.isLowFarOut()) {
                drawLowFarOut(aRadius / 2.0, g2,
                        xx + state.getBarWidth() / 2.0, minAxisValue);
            }
        }
        // collect entity and tool tip information...
        if (state.getInfo() != null && box != null) {
            EntityCollection entities = state.getEntityCollection();
            if (entities != null) {
                addItemEntity(entities, dataset, row, column, box);
            }
        }

    }


    /**
     * Draws two dots to represent the average value of more than one outlier.
     *
     * @param point  the location
     * @param boxWidth  the box width.
     * @param oRadius  the radius.
     * @param g2  the graphics device.
     */
    private void drawMultipleEllipse(Point2D point, double boxWidth,
                                     double oRadius, Graphics2D g2)  {

        Ellipse2D dot1 = new Ellipse2D.Double(point.getX() - (boxWidth / 2)
                + oRadius, point.getY(), oRadius, oRadius);
        Ellipse2D dot2 = new Ellipse2D.Double(point.getX() + (boxWidth / 2),
                point.getY(), oRadius, oRadius);
        g2.draw(dot1);
        g2.draw(dot2);
    }


    /**
     * Draws a dot to represent an outlier.
     *
     * @param point  the location.
     * @param oRadius  the radius.
     * @param g2  the graphics device.
     */
    private void drawEllipse(Point2D point, double oRadius, Graphics2D g2) {
        Ellipse2D dot = new Ellipse2D.Double(point.getX() + oRadius / 2,
                point.getY(), oRadius, oRadius);
        g2.draw(dot);
    }

    /**
     * Draws a triangle to indicate the presence of far-out values.
     *
     * @param aRadius  the radius.
     * @param g2  the graphics device.
     * @param xx  the x coordinate.
     * @param m  the y coordinate.
     */
    private void drawHighFarOut(double aRadius, Graphics2D g2, double xx,
                                double m) {
        double side = aRadius * 2;
        g2.draw(new Line2D.Double(xx - side, m + side, xx + side, m + side));
        g2.draw(new Line2D.Double(xx - side, m + side, xx, m));
        g2.draw(new Line2D.Double(xx + side, m + side, xx, m));
    }


    /**
     * Draws a triangle to indicate the presence of far-out values.
     *
     * @param aRadius  the radius.
     * @param g2  the graphics device.
     * @param xx  the x coordinate.
     * @param m  the y coordinate.
     */
    private void drawLowFarOut(double aRadius, Graphics2D g2, double xx,
                               double m) {
        double side = aRadius * 2;
        g2.draw(new Line2D.Double(xx - side, m - side, xx + side, m - side));
        g2.draw(new Line2D.Double(xx - side, m - side, xx, m));
        g2.draw(new Line2D.Double(xx + side, m - side, xx, m));
    }

}