code: @Execute
      public HtmlResponse delete(final DeleteForm form) {
          validate(form, messages -> {}, () -> asListHtml());
          verifyToken(() -> asListHtml());
          final String docId = form.docId;
          try {
              final QueryBuilder query = QueryBuilders.termQuery(fessConfig.getIndexFieldDocId(), docId);
              fessEsClient.deleteByQuery(fessConfig.getIndexDocumentUpdateIndex(), query);
              saveInfo(messages -> messages.addSuccessDeleteDocFromIndex(GLOBAL));
          } catch (final Exception e) {
              throwValidationError(messages -> messages.addErrorsFailedToDeleteDocInAdmin(GLOBAL), () -> asListHtml());
          }
          return asListHtml();
      }
docs: -------