/**
     *  <p> This method is responsible for generating the content and
     *      returning an InputStream to that content.  It is also
     *      responsible for setting any attribute values in the
     *      {@link DownloadServlet#Context}, such as
     *      {@link DownloadServlet#EXTENSION} or
     *      {@link DownloadServlet#CONTENT_TYPE}.</p>
     */
    public InputStream getInputStream(DownloadServlet.Context ctx) {
    HttpServletRequest request =
        (HttpServletRequest) ctx.getServletRequest();

    String pathInfo = request.getPathInfo();
    if (pathInfo == null || pathInfo.length() == 0) {
        return null;
    }
    ServletContext sc = ctx.getServletConfig().getServletContext();

    String servletPath = request.getServletPath();
    String realPath = sc.getRealPath(servletPath);
    File file = new File(realPath+pathInfo);
    InputStream is = null;
 try {
        is = new FileInputStream(file);
    } catch (FileNotFoundException ex) {
        //try classpath
        is = getClass().getClassLoader().getResourceAsStream(servletPath.substring(1)+pathInfo);
    }
    int index = pathInfo.lastIndexOf('.');
    // Set the extension so it can be mapped to a MIME type
    String extnsn = pathInfo.substring(index + 1);
    ctx.setAttribute(DownloadServlet.EXTENSION, extnsn);    // NOI18N

    ctx.setAttribute("filePath", is);

    // Return an InputStream to the tmpFile
    return is;
    }