Bug 136770 Cannot view report document from web viewer
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
* Get named parameters from http request. parameter names and values are
	 * all in iso-8859-1 format in request.
	 * 
	 * @param request
	 *            incoming http request
	 * @param parameterName
	 *            parameter name in UTF-8 format
	 * @return
	 */
	public static Set getParameterValues( HttpServletRequest request,
			String parameterName )
	{
		return getParameterValues( request, parameterName, true );
	}
	/**
	 * Get report file name.
	 * 
	 * @param request
	 *            http request
	 * @return report file name
	 */
	public static String getReport( HttpServletRequest request )
	{
		String filePath = getParameter( request, PARAM_REPORT );
		filePath = preProcess( filePath );
		filePath = createAbsolutePath( filePath );
		return filePath;
	}
	/**
	 * Get report document name.