CEP on Ulitzer

You can create a sophisticated application that implements complex algorithms, but in many cases you sell its GUI part to your users. The presentation layer of plain vanilla HTML/JSP-based Web applications is usually pretty basic unless you use specialized software. Today we are testing the charting engine WebCharts3D 5.0 from GreenPoint.

Let me introduce myself: I am a Java developer with basic JSP skills and a stopwatch on my desk. My task is to show you how you can create a Web page in less than 20 minutes that retrieves the sales data from an external data source and displays them as a chart using WebCharts3D.

To set the scene, I downloaded and installed the beta version of the Tomcat 5.5 servlet container from Apache (http://jakarta.apache.org/tomcat/). Actually, WebCharts3D comes with an embedded Web server that can be used for test purposes, but I decided to use a commercial-grade server. I've also created a plain comma-delimited sales_data file with the annual sales data in a cross-tab form:

John		2002	7171.30
Alex		2002	5921.00
Mary		2002	6273.00
Sam		2002	5092.00
John		2003	2980.30
Alex		2003	3928.00
Mary		2003	8905.00
Sam		2003	3093.90
John		2004	5095.30
Alex		2004	2000.00
Mary		2004	2870.00
Sam		2004	4900.90

Start WebCharts3D, and you'll see its Designer screen with a large variety of charts to choose from (some of them are shown in Figure 1). You can select one of the following: bar, pie, radar, dial, statistical, and Gantt charts.

Designing a Chart
Every chart consists of two parts: a style and a model (remember the MVC paradigm?). Internally, both style and model are generated in XML format.

For this demo I've selected one of the flavors of a 3D bar chart (it's the third icon in the first row in Figure 1). This opened the screen shown in Figure 2. On the right side you can modify multiple properties of the chart starting with colors to event processing.

To populate the chart with the data from our sales file just go to the XML Model tab, check the Crosstab box, press the button "Import From File" and select our sales_data file. You'll see the table with our data and XML with hard-code sales values. Switch to the tab Design again to make sure that the chart is populated with our data.

Since we don't want to create charts with hard-coded data, go to the tab CodeView, press the Options button, and select the model "Imported File" (for databases you'd select the model "Database Query"). The Designer immediately generates the JSP code as shown in Listing 1.

Please note that the line myChart.linkTo() points at my sales_data file as the data source.

You can immediately see how the chart will look in your Web browser. Let's launch the embedded server: select the Console tab at the bottom of the Designer's screen and press the Start button and wait a second for the message "Server Started on port 8802." To see your Sales chart just open your Web browser and enter the following URL: http://localhost:8802 as in Figure 3.

The next code snippet shows how you can get the data from a database using the JDBC-ODBC bridge:

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection dbConn = DriverManager.getConnection("jdbc:odbc:...",
"admin" , "User Password");
myChart.linkTo(dbConn,"select ProductName, Sales from Sales",false, false);

Note the links at the bottom of the screen in Figure 3. You've guessed it right! For example, press the PDF link, and see your chart in Adobe Acrobat Reader if you have it installed.

Flash and SVG-Animated Charts Some of the chart formats can be animated. To animate our sales chart using the Flash file format just select the SWF or SVG link while watching the chart in the embedded HTTP server (or set the chart type to SWF or SVG). You'll see how the bars start growing one after another. You can change their order of appearance by setting the Morphing attributes of your chart elements in the Designer. The charts can grow vertically or horizontally, you can add a blurring effect, and set the length and quality of your movie by playing with the framesCount and framesPerSecond properties. You can animate the entire chart or by row or by column. You can control the time of the animation, pauses between fazes, etc. If you want to get a "wow" from your users, add the animation to your charts.

Deploying the Sales Chart Under Tomcat
Just follow the simple steps below to deploy our chart under Tomcat (the process is literally the same in any J2EE-compliant servlet container):

1. Copy ws50.jar into the WEB-INF\lib directory to make WebCharts3D-supporting classes available to Tomcat.
2. Create the file getImage.jsp in the root directory of the Web server. This file is used internally to retrieve the generated image temporarily stored on the server. Go to Designer's File | Setup menu, select the Server tab and enter the application home directory, which in the case of a default Tomcat installation is C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\ROOT
3. Restart Tomcat.
4. In the Designer's CodeView tab press the Save button and save the generated code shown in Listing 1 in Tomcat's root directory as sales.jsp. In the real world you'd copy and paste this code into one of your existing JSPs.
5. Point your browser at http://localhost:8080/sales.jsp and you'll see a screen as in Figure 4.

The Web page is ready and my stopwatch shows that the entire process including the WebCharts installation took about 20 minutes. Of course, I've only demonstrated a small part of the WebCharts3D functionality, but the result is pretty impressive.