Question

I am trying to programmatically create a Radar Chart in my app with BIRT. It seems that BIRT lacks documentation so I am struggling with it (I’m wondering how it can be so popular with so little documentation).

So my problem is that I don’t know the API and the sequence of action I have to invoke on it to have a fully integrated Chart. All I want to do is fetch some data from a DB and display them in a RADAR CHART (like theses ones : how to normalize statistics for a radar chart)

So for now, I have created a Servlet like this :

public class ChartRenderingServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private ChartEngine chartEngine = null;
    private Chart chart = null;
    private IDeviceRenderer iDeviceRenderer = null;
    private IDisplayServer iDisplayServer = null;
    private IGenerator iGenerator = null;
    private String fontName = "Arial";
    private float size = 10;
    private boolean bBold = false;
    private boolean bItalic = false;
    private ColorDefinition cd = ColorDefinitionImpl.BLACK();

    /**
     * @see HttpServlet#HttpServlet()
     */
    public ChartRenderingServlet() {
        super();
        // Starting platform
        PlatformConfig platformConfig = new PlatformConfig();
        platformConfig.setProperty("STANDALONE", true);

        // Creating chart Engine
        chartEngine = ChartEngine.instance(platformConfig);
        iGenerator = chartEngine.getGenerator();

        try {
            iDeviceRenderer = chartEngine.getRenderer("dv.PNG");
            iDisplayServer = iDeviceRenderer.getDisplayServer();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        RunTimeContext context;
        chart = ChartWithoutAxesImpl.create();
        chart.setType("RADAR");

        try {
            // PREPARE PHASE
            context = Generator.instance().prepare(chart, null, null, ULocale.getDefault());

            // BIND PHASE
            //Long id = Long.valueOf(request.getParameter("id"));
            NumberDataSet orthoValues = NumberDataSetImpl.create(new double[] {25, 35, 15, 5, 20});
            RadarSeries radarSeries = RadarSeriesImpl.create();
            radarSeries.setDataSet(orthoValues);

            // RENDER PHASE
            GeneratedChartState generatedChartState = iGenerator.build(iDisplayServer, chart, null, null, context);
            iGenerator.render(iDeviceRenderer, generatedChartState);
        } catch (ChartException e) {
            e.printStackTrace();
        }

    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

Any help would really be appriciated because I don’t even know whether this is correct or not.

Thanks a lot,

Answer 1

Never mind,

when developing BIRT report-powered app, try to take a higher abstraction level when coding. I mean, there’s no need to code against the low-level API : just take your rptdesign file and leverage the Birt Runtime API to code the app directly. If I can suggest something, I would say use the main API available which is Report Engine API, it will speed up your development.

And the cool thing with it is that, you have a lot of documentation available since it’s the most common way of developing a BIRT-powered app.

tchusss …