code: private JnlpResource locateResource( DownloadRequest dreq )
              throws IOException, ErrorResponseException
      {
          if ( dreq.getVersion() == null )
          {
              return handleBasicDownload( dreq );
          }
          else
          {
              return handleVersionRequest( dreq );
          }
      }
docs: Interprets the download request and convert it into a resource that is
  part of the Web Archive.