TOP N-Analysis using JFreeChart

This post will narrate about plotting a Top-N analysis chart using JFreeChart.

Top-N analysis is used in many occasions like "No of defects pending" per tester or "outstanding components with more defects". When i tried to implement the same in JFreeChart i faced lot of issues, so that of sharing my learning to JFreeChart users. Here i have used bar chart with horizontal orientation. The percentage bar is made invisible from user view, by drawing the same in white color. I have also suppressed legends from view.

//set of headers to be included

import java.awt.Color;

import java.awt.Font;

import java.io.*;

import java.text.DecimalFormat;

import org.jfree.chart.JFreeChart;

import org.jfree.chart.ChartFactory;

import org.jfree.chart.ChartUtilities;

import org.jfree.chart.labels.CategoryItemLabelGenerator;

import org.jfree.chart.labels.StandardCategoryItemLabelGenerator;

import org.jfree.chart.plot.PlotOrientation;

import org.apache.poi.hssf.usermodel.HSSFRow;

import org.apache.poi.hssf.usermodel.HSSFCell;

import org.apache.poi.hssf.usermodel.HSSFSheet;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import org.jfree.data.category.DefaultCategoryDataset;

import org.jfree.chart.axis.NumberAxis;

import org.jfree.chart.renderer.category.BarRenderer;

import org.jfree.ui.ApplicationFrame;

import java.io.File; 

import org.jfree.chart.plot.CategoryPlot;

import org.jfree.chart.axis.AxisLocation;

import org.jfree.chart.axis.CategoryAxis;

  

public class HorizonBarChart extends ApplicationFrame

{

         @SuppressWarnings("deprecation")                 

         //Constructor

         HorizonBarChart(final String title,String ipfilename,String Datasheetname,String opfilename)

         {

           super(title);                                             

           DefaultCategoryDataset dataset  = createDataset(ipfilename,Datasheetname);          

           JFreeChart chart = ChartFactory.createBarChart( title, 

                    "", 

                   "# of defect pending", 

                   dataset, 

                   PlotOrientation.HORIZONTAL,  //Sets chart orientation as Horizontal

                   false, 

                   false, 

                  false );                         

           final CategoryPlot plot = chart.getCategoryPlot();

         //Customization of chart

        plot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_LEFT);

        plot.setBackgroundPaint(null);

        plot.setOutlineVisible(false);             

        plot.getRenderer().setSeriesPaint(0, new Color(0, 0, 255));   

        //This line ensure the other bar is not visible to user at all, since they are drawn  in white color
        plot.getRenderer().setSeriesPaint(1, new Color(255, 255, 255));  

  

       //Only numbers are displayed in range axis

        final NumberAxis rangeAxis = (NumberAxis)plot.getRangeAxis();     

        rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());         

        //sets font & margin on domain axis

        final CategoryAxis domainAxis = plot.getDomainAxis();     

        domainAxis.setCategoryMargin(0.2);      

        Font ft = new Font("SansSerif",Font.BOLD|Font.ROMAN_BASELINE, 12 ) ;

        domainAxis.setTickLabelFont(ft);

        domainAxis.setMaximumCategoryLabelWidthRatio(1);          

       

        BarRenderer renderer = ( BarRenderer)plot.getRenderer();

        renderer.setItemMargin(0.3);       

        renderer.setBaseItemLabelGenerator(new StandardCategoryItemLabelGenerator());

        renderer.setBaseItemLabelsVisible(true);

      

          // " % " is shown next to series value

          CategoryItemLabelGenerator categoryLabel = new StandardCategoryItemLabelGenerator("{2}",
          new DecimalFormat("0%"));     

          renderer.setSeriesItemLabelGenerator(1,categoryLabel);                               

          //series value are shown next to bars

          renderer.setSeriesItemLabelsVisible(0, true);

          renderer.setSeriesItemLabelsVisible(1, true);

                               

          Font rft = new Font("SansSerif",Font.BOLD|Font.ROMAN_BASELINE, 12 ) ;

          renderer.setSeriesItemLabelFont(0, rft);

          renderer.setSeriesItemLabelFont(1, rft);               

          //Chart generation       

           try {

              ChartUtilities.saveChartAsJPEG(new File(opfilename), chart,800, 700);      

               } catch (IOException e) {

              System.out.println("Problem in creating chart.");

              e.printStackTrace();

              }//End of try

           }                     

           //Main function 

           public static void main(String args[]) throws Exception       

               {   new VerticalBarChart("chart title","No such file","Data_2","No such file");  }

           private static DefaultCategoryDataset createDataset(String filename,String sheetname) {

                 DefaultCategoryDataset dataset1= new DefaultCategoryDataset();

                  Double x=0.0; 

                  String z=null;   

                  try

                               {                   

                                   FileInputStream fs =new FileInputStream(filename);        

                                    HSSFWorkbook wb = new HSSFWorkbook(fs);  

                                     HSSFSheet sheet = wb.getSheet(sheetname);      

                                     //The below section illustrates how to insert the values in dataset.

                                     //Please add your appropriate logic here.

                                     //This section is just to give an abstract view about dataset values

                                                 HSSFCell cell1 = sheet.getRow(r).getCell(col);

                                                 x=(double)cell1.getNumericCellValue();                                               

                                                 if(col==row.getLastCellNum()-1)

                                                     {

                                                          //To set the value in terms of percentage                                

                                                           x=x/100;  

                                                     }

                                                HSSFCell cell3 = sheet.getRow(r).getCell(row.getLastCellNum());

                                                 z=cell3.toString();                                               

                                                dataset1.addValue(x,"y-String to be constant",z);

                                        }

                  }//try       

                 catch(Exception e){

                                  e.printStackTrace();}

                 return dataset1;

              }

}

Input for this chart sample, is cited below.Happy Analysis!!