code: public Content getUserHeaderFooter(boolean header) {
          String content;
          if (header) {
              content = replaceDocRootDir(configuration.header);
          } else {
              if (configuration.footer.length() != 0) {
                  content = replaceDocRootDir(configuration.footer);
              } else {
                  content = replaceDocRootDir(configuration.header);
              }
          }
          Content rawContent = new RawHtml(content);
          return rawContent;
      }
docs: Get user specified header and the footer.
  
  @param header if true print the user provided header else print the
  user provided footer.