chartservlet.java

JWebChart is a simple package to allow anyone to render complex charts using a Java Servlet. The pro

/*
 * ChartServlet.java
 * 
 * Created on 08-Feb-2006
 *
 * JWebChart
 * Copyright (C) 2006 by Luke Trevorrow (www.axioma.org.uk)
 */

package uk.org.axioma.servlet;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.servlet.ChartDeleter;
import org.jfree.chart.servlet.ServletUtilities;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.time.Second;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.xml.DatasetReader;
import org.jfree.data.xy.XYSeries;

import uk.org.axioma.chart.CategoryChart;
import uk.org.axioma.chart.MeterChart;
import uk.org.axioma.chart.PieChart;
import uk.org.axioma.chart.XYChart;

/**
 * <p>
 * The ChartServlet object 
 * </p>
 * @author <a href="mailto:[e-mail]">Luke Trevorrow</a>
 * @version 0.3
 * 
 */
public class ChartServlet extends HttpServlet {

	/**
	 * autogenerated serialVersionUID
	 */
	private static final long serialVersionUID = 6748895383151504466L;


	/**
	 * 
	 */
	public ChartServlet() {
		super();
	}
	
    /**
     * Init method.
     *
     * @throws ServletException never.
     */
    public void init() throws ServletException {
        return;
    }

    /**
     * Service method.
     *
     * @param request  the request.
     * @param response  the response.
     *
     * @throws ServletException ??.
     * @throws IOException ??.
     */
    public void service(HttpServletRequest request, 
                        HttpServletResponse response)
            throws ServletException, IOException {

        HttpSession session = request.getSession();
        Enumeration en = request.getParameterNames();
        Map<String,String[]> map = new HashMap<String,String[]>(request.getParameterMap());
        JFreeChart jfc = null;
        
        String series = null;
        int width = 300, height = 200;
        
        /*PrintWriter out = response.getWriter();
        response.setContentType("text/html");
        out.println("<H4>");*/
        
        // go through the hash map and extract the core values.
        // extract the rest in the createChart methods
        if (map.containsKey("Series")) {
        	// use the getParameter method rather than the map to get the string array as I am sure this will be faster
        	series = request.getParameter("Series");
        	map.remove("Series");
        	//out.println("<br>Graph : " + series);
        }
        
        if (map.containsKey("Width")) {
        	width = Integer.valueOf(request.getParameter("Width")).intValue();
        	map.remove("Width");
        	//out.println("<br>Width : " + width);
        }
        
        if (map.containsKey("Height")) {
        	height = Integer.valueOf(request.getParameter("Height")).intValue();
        	map.remove("Height");
        	//out.println("<br>Height : " + height);
        }
        
        // create the chart
        if (series.equalsIgnoreCase("Pie")) {
        	jfc = createPie(map, request); 	
        } else if (series.equalsIgnoreCase("Category")) {
        	jfc = createCategory(map, request);
        } else if (series.equalsIgnoreCase("XY")) {
        	jfc = createXY(map, request);
        } else if (series.equalsIgnoreCase("Meter")) {
        	jfc = createMeter(map, request);
        }
                
        // save the image for display
        String filename = ServletUtilities.saveChartAsPNG(jfc,width,height,null);
        //out.println(filename);
        
        // Check the file exists
        File file = new File(System.getProperty("java.io.tmpdir"), filename);
        if (!file.exists()) {
            throw new ServletException(
                "File '" + file.getAbsolutePath() + "' does not exist"
            );
        }

        //  Check that the graph being served was created by the current user
        //  or that it begins with "public"
        boolean isChartInUserList = false;
        ChartDeleter chartDeleter = (ChartDeleter) session.getAttribute(
            "JFreeChart_Deleter"
        );
        if (chartDeleter != null) {
            isChartInUserList = chartDeleter.isChartAvailable(filename);
        }

        boolean isChartPublic = false;
        if (filename.length() >= 6) {
            if (filename.substring(0, 6).equals("public")) {
                isChartPublic = true;
            }
        }
        
        boolean isOneTimeChart = false;
        if (filename.startsWith(ServletUtilities.getTempOneTimeFilePrefix())) {
            isOneTimeChart = true;   
        }

        if (isChartInUserList || isChartPublic || isOneTimeChart) {
            //  Serve it up
            ServletUtilities.sendTempFile(file, response);
            if (isOneTimeChart) {
                file.delete();
            }
        } else {
            throw new ServletException("Chart image not found");
        }
        
        // For keys of a map
        //for (Iterator<String> it=map.keySet().iterator(); it.hasNext(); ) {
            //Object key = it.next();
            //out.println("Key : " + key);
        //}
        // just return the filename to the browser for now
        //out.println("</H4>");
        //out.println("<TR>");
        //out.println("<TH CLASS=\"data\">");
        //out.println("filename");
        //out.println("</TH>");
        //out.println("</TR>");
        //out.print("<TD CLASS=\"data\">");
        //out.println(filename);
        //out.println("</TD>");
    }
    
    /**
     * Create meter chart method.
     * @param data which can consist of elements such as:
     * <ul>
     * <li> Type - the type of chart: either Chord, Pie, Circle, RAGChord, RAGPie, or RAGCircle.</li>
     * <li> Title - the title of the chart.</li>
     * <li> Value - the value range for the meter.</li>
     * <li> Units - the unit of measure for the meter.</li>
     * <li> Range - the range for the meter.</li>
     * <li> Interval - the interval ranges for the legend. Format is name=startval,endval, eg: Low=0,70</li>
     * </ul>
     * @param req which is the Http Servlet Request
     * 
     * @return JFreeChart
     * @throws ServletException
     * 
     */
    private JFreeChart createMeter(Map<String, String[]> data, HttpServletRequest req)
    		throws ServletException {
    	MeterChart mc = new MeterChart();

    	// what type?
    	if (data.containsKey("Type")) {
    		String type = req.getParameter("Type");
    		if (type.equalsIgnoreCase("Chord")) {
            	mc.type = MeterChart.TYPECHORD;
            } else if (type.equalsIgnoreCase("Circle")) {
            	mc.type = MeterChart.TYPECIRCLE;
            } else if (type.equalsIgnoreCase("Pie")) {
            	mc.type = MeterChart.TYPEPIE;
            } else if (type.equalsIgnoreCase("RAGChord")) {
            	mc.type = MeterChart.TYPERAGCHORD;
            } else if (type.equalsIgnoreCase("RAGCircle")) {
            	mc.type = MeterChart.TYPERAGCIRCLE;
            } else if (type.equalsIgnoreCase("RAGPie")) {
            	mc.type = MeterChart.TYPERAGPIE;
            }
    		data.remove("Type");
    	}
    	
    	// set the title for the Pie Chart
    	if (data.containsKey("Title")) {
    		mc.title = req.getParameter("Title");
    		data.remove("Title");
    	}
    	// set the units of measure
    	if (data.containsKey("Units")) {
    		mc.units = req.getParameter("Units");
    		data.remove("Units");
    	}
    	// set the range
    	if (data.containsKey("Range")) {
    		mc.range = req.getParameter("Range");
    		data.remove("Range");
    	}
    	// set the value
    	if (data.containsKey("Value")) {
    		mc.dataset.setValue(Double.valueOf(req.getParameter("Value")));
    		data.remove("Value");
    	}
    	
    	mc.interval = data;
    	//MeterChart.out = out;
    	
    	// create the chart
    	JFreeChart chart = mc.getChart();
    	return chart;
    }
    
    /**
     * Create pie chart method.
     * 
     * @param data which can consist of elements such as:
     * <ul>
     * <li> Type - the type of chart: either 2D, 3D, or Ring.</li>
     * <li> Title - the title of the chart.</li>
     * <li> XMLFile - the XML file name if applicable.</li>
     * <li> data - the data to plot. Format is name=value&name=value, eg: Fish=70&Chips=66.</li>
     * </ul>
     * @param req which is the Http Servlet Request	
     *
     * @return JFreeChart
     * @throws ServletException
     * 
     */
    private JFreeChart createPie(Map<String, String[]> data, HttpServletRequest req) 
    		throws ServletException {