reportContext.setPersistentGlobalVariable("total",this.getValue().toString);

tmp = "";
tmp = reportContext.getPersistentGlobalVariable("total");
this.setDisplayValue(tmp);

public class PrintReport {

	private final static String LOG_DIR = "./birt/logs/";
	private final static String OUTPUT_DIR = "./birt/outputs/";
	private final static String REPORT = "./birt/reports/Report06.rptdesign";
	private final static String BINARY_REPORT = "./birt/reports/Binary_Report06.rptdesign";

	public static void main(String[] args) {

		PrintReport printReport = new PrintReport();

		try {
			printReport.generateReport();
		} catch (BirtException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	public void generateReport() throws BirtException {
		IReportEngine reportEngine = null;
		IReportRunnable reportRunnable = null;
		IReportDocument reportDocument = null;
		IRunTask runTask = null;
		IRenderTask renderTask = null;

		EngineConfig engineConfig = new EngineConfig();
		IPlatformContext context = new PlatformFileContext();

		engineConfig.setLogConfig(LOG_DIR, Level.FINE);
		engineConfig.setEngineContext(context);
		try {
			// start the eclipse Platform
			Platform.startup(engineConfig);
			// get ReportEngine
			IReportEngineFactory reportEngineFactory = (IReportEngineFactory) Platform
					.createFactoryObject(IReportEngineFactory.EXTENSION_REPORT_ENGINE_FACTORY);
			reportEngine = reportEngineFactory.createReportEngine(engineConfig);
			// create new Instance of report Report06.rptdesing
			reportRunnable = reportEngine.openReportDesign(REPORT);

			// Generate the Report
			runTask = reportEngine.createRunTask(reportRunnable);
			runTask.run(BINARY_REPORT);

			// Binary ReportDocument
			reportDocument = reportEngine.openReportDocument(BINARY_REPORT);

			// Render the Report
			renderTask = reportEngine.createRenderTask(reportDocument);

			// Create Output-File
			ByteArrayOutputStream fso = new ByteArrayOutputStream();
			PDFRenderOption options = new PDFRenderOption();
			options.setOutputStream(fso);
			options.setOutputFileName(OUTPUT_DIR + "File.pdf");
			options.setOutputFormat(PDFRenderOption.OUTPUT_FORMAT_PDF);
			options.setEmitterID(PDFRenderOption.OUTPUT_EMITTERID_PDF);
			options.setSupportedImageFormats("PNG");

			// render the report
			renderTask.setRenderOption(options);
			renderTask.setPageNumber(1);
			renderTask.render();

			// Finished
			renderTask.close();
			reportDocument.close();
			runTask.close();
			reportEngine.shutdown();
			Platform.shutdown();
			System.out.println("Finished");

		} catch (BirtException e) {
			e.printStackTrace();
			reportEngine.destroy();
		}
	}
}

// BinaryReportDocument
reportDocument = reportEngine.openReportDocument(BINARY_REPORT);

// Special: list TableOfContents of report
TOCNode tableOfContentsNode = reportDocument.findTOC(null);
java.util.List children = tableOfContentsNode.getChildren();
if (children != null && children.size() > 0) {
	for (int i = 0; i < children.size(); i++) {
		TOCNode child = (TOCNode) children.get(i);
		System.out.println("Node ID " + child.getNodeID());

		System.out.println("Node Display String "
				+ child.getDisplayString());
		System.out.println("Node Bookmark " + child.getBookmark());
	}
}

// Render the Report
renderTask = reportEngine.createRenderTask(reportDocument);