docs: @Override
      public void doRender(Invocation inv) throws Exception {
          if (StringUtils.isEmpty(text)) {
              return;
          }
          
          if (logger.isDebugEnabled()) {
          	logger.debug("trying to render text:" + text);
          }
          
          HttpServletResponse response = inv.getResponse();
          String oldEncoding = response.getCharacterEncoding();
          if (StringUtils.isBlank(oldEncoding) || oldEncoding.startsWith("ISO-")) {
              String encoding = inv.getRequest().getCharacterEncoding();
              Assert.isTrue(encoding != null);
              response.setCharacterEncoding(encoding);
              if (logger.isDebugEnabled()) {
                  logger.debug("set response.characterEncoding by default:"
                          + response.getCharacterEncoding());
              }
          }
          
          if (response.getContentType() == null) {
              response.setContentType("text/html");
              if (logger.isDebugEnabled()) {
                  logger.debug("set response content-type by default: "
                          + response.getContentType());
              }
          }
          sendResponse(response, text);
      }