Bug 180118 Enhance to print out source stack trace in preview mode.[0002]
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/presentation/aggregation/layout/EngineFragment.java
{
	/**
	 * Anything before do service.
	 * 
	 * @param request
	 *            incoming http request
	 * @param response
	 *            http response
	 * @exception ServletException
	 * @exception IOException
	 */
	protected void doPreService( HttpServletRequest request,
			HttpServletResponse response ) throws ServletException, IOException
	{
		String format = ParameterAccessor.getFormat( request );
		String openType = ParameterAccessor.getOpenType( request );
		if ( IBirtConstants.SERVLET_PATH_DOWNLOAD.equalsIgnoreCase( request
				.getServletPath( ) ) )
		{
			response.setContentType( "text/plain; charset=utf-8" ); 
			response
					.setHeader(
							"Content-Disposition", "attachment; filename=exportdata.csv" ); 
		}
		else
		{