Bug 165188 logging per report
Setting up a dedicated (birt) report server, which serves all our web apps, leads to a logging desaster. Birtegine logs all messages to one file. There's no info which rptdesign caused the logmessage or who (e.g. user) caused the logmessage. Retrieving who/which rpt caused some logmessage is not possible! There are two possible solutions: (a) prefixing each logmessage with a userdefineable message (task.setLogprefix("myprefix")) (b) set an outputstream for each task (task.setLoggingOutputStream(outputstream)) to split the huge logfile to many small pieces.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/ReportEngine.java
* @param fileName
	 *            the report document name. report document is an archive in
	 *            BIRT.
	 * @return A handle to the report document
	 * @throws EngineException
	 *             throwed when the report document archive does not exist, or
	 *             the file is not a valud report document
	 */
	public IReportDocument openReportDocument( String fileName )
			throws EngineException
	{
		logger.log( Level.FINE,
				"ReportEngine.openReportDocument: fileName={0} ", fileName );
		return helper.openReportDocument( fileName );
	}
	/**
	 * creates a task that allows data extraction from a report document
	 * 
	 * @param reportDocument
	 *            a handle to an IReportDocument object
	 * @return a task that renders a report to an output format
	 */
	public IDataExtractionTask createDataExtractionTask(
			IReportDocument reportDocument )
	{
		logger.log( Level.FINE,
				"ReportEngine.createDataExtractionTask: reportDocument={0} ", reportDocument );
		return helper.createDataExtractionTask( reportDocument );
	}
	/**