Pentaho reports with Java API

Intro

I found very little documentation with examples about how to use pentaho reporting API in Java. Most of the time I had trouble in establishing dependencies necessary to get the pentaho reporting to generate the reports out from the designer generated files with a ".prpt" extension. The story got even more complicated when I tried generating the graphs. The exceptions I encountered had very little solutions available on-line. I've decided for the 5.0.3 version because there are couple of books available that describe how to use that specific version. Moreover gradle seems to be very popular now-days so I decided to list the dependencies with it.

Dependency list

You will find most of the dependencies available on the pentaho repository. It might come as a surprise to you but there are also a lot of other dependencies that have to be included. JFreeChart is the first.

• "org.jfree:jfreechart:1.0.17"
• "pentaho-reporting-engine:pentaho-reporting-engine-classic-core:5.0.3"
• "pentaho-reporting-engine:pentaho-reporting-engine-classic-extensions:5.0.3"
• "pentaho-reporting-engine:pentaho-reporting-engine-classic-extensions-xpath:5.0.3"
• "pentaho-reporting-engine:pentaho-reporting-engine-legacy-charts:5.0.3"
• "pentaho-library:libloader:5.0.3"
• "pentaho-library:libxml:5.0.3"
• "pentaho-library:libserializer:5.0.3"
• "pentaho-library:libformula:5.0.3"
• "pentaho-library:libfonts:5.0.3"
• "pentaho-library:libformat:5.0.3"
• "pentaho-library:libdocbundle:5.0.3"
• "pentaho-library:libswing:5.0.3"
• "pentaho-library:flute:5.0.3"
• "pentaho-library:libcss:5.0.3"
• "pentaho-library:libpixie:5.0.3"
• "pentaho-library:libsparkline:5.0.3"
• "pentaho-library:libbase:5.0.3"
• "pentaho-library:librepository:5.0.3"
• "com.lowagie:itext:2.1.7"
• "com.lowagie:itext-rtf:2.1.7"
• "org.apache.poi:poi:3.9"
• "org.apache.poi:poi-ooxml:3.9"
• "bsf:bsf:2.4.0"
• "rhino:js:1.6R7"

I hope this list will save somebody some time. It took me a while to compile it. The last one was a particularly time intensive to find. I found It thanks to the following post: http://forums.pentaho.com/archive/index.php/t-152813.html

Generating reports from .prpt files

If you ever come across this text you probably won't have trouble loading the MasterReport from the file system or some similar source. In my humble opinion the most complicated output format is actually the HTML. In order to get everything to work I had to extend the HtmlPrinter class. Other methods of including graphs were not an option so I had to include the images as Base64

Extending the HtmlPrinter:

        public class YourSuperPrinter class extends HtmlPrinter {

        // constructor
        super(resourceManager);

        // override print
        super.print(logicalPageKey, logicalPage, contentProducer,
            metaData, incremental);

        // we'll need convert the Image to BufferedImage
        private static BufferedImage toBufferedImage(Image img) {
            if (img instanceof BufferedImage) {
                return (BufferedImage) img;
            }

            BufferedImage bimage = new BufferedImage(
                img.getWidth(null), img.getHeight(null),
                BufferedImage.TYPE_INT_ARGB);

            Graphics2D bGr = bimage.createGraphics();
            bGr.drawImage(img, 0, 0, null);
            bGr.dispose();

            return bimage;
        }

        // override writeImage
        if (image instanceof DefaultImageReference) {
            DefaultImageReference dir = (DefaultImageReference) image;

            if (dir.getImage() != null && encoderType != null) {
                BufferedImage img = toBufferedImage(dir.getImage());

                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                ImageIO.write(img, 
                    encoderType.substring(encoderType.indexOf("/") + 1),
                    baos);
                baos.flush();
                byte[] imageInByte = baos.toByteArray();

                String imageData = Base64.encode(imageInByte);

                return "data:" + encoderType + ";base64," + imageData;
            }
            else {
                return dir.getSourceURLString();
            }
        }

        return super.writeImage(image, encoderType, quality, alpha);
    

Now that you have your Super printer you can generate html:

        MasterReport rep;
        AbstractReportProcessor reportProcessor;

        // BEGIN HTML specific
        StreamRepository tp = new StreamRepository(outputStream);
        ContentLocation tr = tp.getRoot();
        HtmlOutputProcessor op = new StreamHtmlOutputProcessor(
            rep.getConfiguration());
        HtmlPrinter printer = new YourSuperPrinter(
            rep.getResourceManager());

        printer.setContentWriter(tr, 
            new DefaultNameGenerator(tr, "index", "html"));
        printer.setDataWriter(null, null);
        printer.setUrlRewriter(new FileSystemURLRewriter());

        op.setPrinter(printer);

        reportProcessor = new StreamReportProcessor(rep, op);
        // END HTML specific

        reportProcessor.processReport();

        outputStream.close();
        outputStream.flush();
    

If everything went fine you should be generating super graphics and charts in your reports.

Let's mention other report formats together with their specifics:

Excel

        FlowExcelOutputProcessor target = new FlowExcelOutputProcessor(
            rep.getConfiguration(), outputStream, 
            rep.getResourceManager());
        reportProcessor = new FlowReportProcessor(rep, target);

        // if you want to download the file
        response.setContentType("application/vnd.ms-excel");
        response.addProperty(
            "Content-Disposition", "attachment; filename=hello.xls");
    

PDF

        PdfOutputProcessor outputProcessor = new PdfOutputProcessor(
            rep.getConfiguration(), outputStream, 
            rep.getResourceManager());
        reportProcessor = new PageableReportProcessor(
            rep, outputProcessor);

        // if you want to download the file
        response.setContentType("application/pdf");
        response.addProperty(
            "Content-Disposition", "attachment; filename=hello.pdf");
    

CSV

        StreamCSVOutputProcessor outputProcessor = 
            new StreamCSVOutputProcessor(outputStream);
        reportProcessor = new StreamReportProcessor(rep, outputProcessor);

        // if you want to download the file
        response.setContentType("text/csv");
        response.addProperty(
            "Content-Disposition", "attachment; filename=hello.csv");
    

RTF

        StreamRTFOutputProcessor outputProcessor = 
            new StreamRTFOutputProcessor(
            rep.getConfiguration(), outputStream, 
            rep.getResourceManager());
        reportProcessor = new StreamReportProcessor(rep,
            outputProcessor);

        // if you want to download the file
        response.setContentType("application/rtf");
        response.addProperty(
            "Content-Disposition", "attachment; filename=hello.rtf");
    

XML

        // no .processReport here, just stream close and flush ...
        XmlTableReportUtil.createStreamXML(report, outputStream);
        outputStream.close();
        outputStream.flush();

        // if you want to download the file
        response.setContentType("application/xml");
        response.addProperty(
            "Content-Disposition", "attachment; filename=hello.xml");
    

TEXT

        // no .processReport here, just stream close and flush ...
        PlainTextReportUtil.createPlainText(report, outputStream);
        outputStream.close();
        outputStream.flush();

        // if you want to download the file
        response.setContentType("application/text");
        response.addProperty(
            "Content-Disposition", "attachment; filename=hello.txt");
    

I hope this post will help somebody, It took me a while to figure all this out.