Pareto Chart Service for Grails Friday, April 17, 2009

Creating a Pareto Chart Service for Grails 

Prerequisites:

• Install grails
• JFreeCharts
• Run: grails create-service ParetoChart
• Got to “./grails-app/service/” replace the “ParetoChartService.groovy” script attached, or copy and paste contents.

Usage:

• In your view, just call the service and its single method.
• E.g., paretoChartService.makeChart()

Notes:

• Pass in a map of data
• def data = ["A":4800, "B":2000, "C#":26, "Java":1901, "SQL":263, "Perl":2500, "PHP":1689, "Python":948, "Ruby":100, "Unix Shell":485
• Need to pass about 5 arguments for
• Map data, i.e.,  [category: value] 
• String Title label
• String y-axis label
• String x-axis label
• List of String subtitles   

paretoChartService.makeChart(data, "My First Chart", "Y Axis", "X Axis", ["Subtitle A", "Subtitle B"] )     

Output:  

Code:

import java.text.*  
import java.awt.Font  
import org.jfree.chart.labels.*  
import org.jfree.chart.renderer.category.*  
import org.jfree.chart.ChartFactory  
import org.jfree.chart.ChartPanel  
import org.jfree.chart.JFreeChart  
import org.jfree.chart.axis.CategoryAxis  
import org.jfree.chart.axis.NumberAxis  
import org.jfree.chart.plot.CategoryPlot  
import org.jfree.chart.plot.DatasetRenderingOrder  
import org.jfree.chart.plot.PlotOrientation  
import org.jfree.chart.title.TextTitle  
import org.jfree.data.DataUtilities  
import org.jfree.data.DefaultKeyedValues  
import org.jfree.data.KeyedValues  
import org.jfree.data.category.CategoryDataset  
import org.jfree.data.general.DatasetUtilities  
import org.jfree.ui.ApplicationFrame  
import org.jfree.ui.RefineryUtilities  
import org.jfree.util.SortOrder  
import org.jfree.chart.ChartUtilities

class ParetoChartService {  
    boolean transactional = true  
    
    def makeChart(Map rawData, String titleLabel, String yAxisLabel, String xAxisLabel, List subTitle) {  
        
        DefaultKeyedValues data = new DefaultKeyedValues()  
   
        //Repackage rawRaw input into data package  
        rawData.each{k,v ->  
            data.addValue(k , new Integer(v))  
        }  
   
        data.sortByValues(SortOrder.DESCENDING)  
        KeyedValues cumulative = DataUtilities.getCumulativePercentages(data)  
        CategoryDataset dataset = DatasetUtilities.createCategoryDataset("Languages", data)  
        
        JFreeChart chart = ChartFactory.createBarChart(
            titleLabel,           // chart title
            yAxisLabel,           // domain axis label
            xAxisLabel,           // range axis label 
            dataset,              // data  
            PlotOrientation.VERTICAL,
            true,                 // include legend
            true,
            false
        )
   
        subTitle.each{   
            chart.addSubtitle(new TextTitle(it))  
        }

        //Create a plot object for more customizations  
        CategoryPlot plot = chart.getCategoryPlot()

        //Create a renderer for our plot, so we can create a label generator  
        CategoryItemRenderer renderer = plot.getRenderer()
   
        //Create a label generator for our bars
        CategoryItemLabelGenerator generator = new StandardCategoryItemLabelGenerator("{2}", new DecimalFormat("0"))
   
        //Give the label generator to the renderer  
        renderer.setItemLabelGenerator(generator)  
        renderer.setItemLabelsVisible(true)  
        renderer.setSeriesItemLabelsVisible(0, true)  
        renderer.setItemLabelFont(new Font("SansSerif", Font.PLAIN, 10))  
   
        //Get handle on domainAxis to change the margins  
        CategoryAxis domainAxis = plot.getDomainAxis()  
   
        //Margin between first bar on the left, and the y-axis line  
        domainAxis.setLowerMargin(0.02)  
   
        //Margin between last bar on the right, and the number-axis line  
        domainAxis.setUpperMargin(0.02)  
    
        NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis()  
        rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits())  
        rangeAxis.setUpperMargin(1.2)

        ************ Part II ****************  
        //Start to prepare pareto line  
        LineAndShapeRenderer renderer2 = new LineAndShapeRenderer()  
   
        //Format lables as percentages  
        NumberFormat formatter = NumberFormat.getPercentInstance()  
   
        //Create generator to feed lables to the renderer  
        CategoryItemLabelGenerator generator2 = new StandardCategoryItemLabelGenerator("{2}", formatter)  
   
        //Give the renderer a handle to the label generator  
        renderer2.setItemLabelGenerator(generator2)  
   
        //Customize the labels  
        renderer2.setItemLabelsVisible(true)  
        renderer2.setSeriesItemLabelsVisible(0, true)  
        renderer2.setItemLabelFont(new Font("SansSerif", Font.PLAIN, 10))  
   
        //Create the dataset for the percentage line  
        CategoryDataset dataset2 = DatasetUtilities.createCategoryDataset("Cumulative", cumulative)  
   
        //Create a secondary axis on the right side for our percents  
        NumberAxis axis2 = new NumberAxis("Percent")  
    
        //Set a margin so all labels above line are visible  
        axis2.setUpperMargin(0.3)  
    
        //Format the text of lables to read as percentages   
        axis2.setNumberFormatOverride(NumberFormat.getPercentInstance())  
    
        //Set all the new values in the plot object   
        plot.setRangeAxis(1, axis2)  
        plot.setDataset(1, dataset2)  
        plot.setRenderer(1, renderer2)  
        plot.mapDatasetToRangeAxis(1, 1)  
    
        //Render our plot  
        //Render primary dataset behind the second   
        plot.setDatasetRenderingOrder(DatasetRenderingOrder.FORWARD)  
    
        //Write chart to .png image  
        ChartUtilities.writeChartAsPNG(new FileOutputStream("./web-app/images/export.png"),chart, 500 , 250)  
    }  
}