code: public void doFilterImpl(ServletRequest pRequest, ServletResponse pResponse, FilterChain pChain) throws IOException, ServletException {
          HttpServletRequest request = (HttpServletRequest) pRequest;
  
          // Get the content type from the request
          String contentType = request.getContentType();
  
          // If the content type is multipart, wrap
          if (isMultipartFileUpload(contentType)) {
              pRequest = new HttpFileUploadRequestWrapper(request, uploadDir, maxFileSize);
          }
  
          pChain.doFilter(pRequest, pResponse);
      }
docs: Examines the request content type, and if it is a
  {@code multipart/*} request, wraps the request with a
  {@code HttpFileUploadRequest}.
  
  @param pRequest The servlet request
  @param pResponse The servlet response
  @param pChain The filter chain
  
  @throws ServletException
  @throws IOException