t.printStackTrace(pw);
            pw.flush();
            return systemHelper.abbreviateLongText(sw.toString());
        } catch (final IOException e) {
            logger.warn("Failed to print the stack trace {}", t.getMessage(), e);
        }
        return StringUtil.EMPTY;
    }

            builder.flush();
            return builder.getOutputStream();
        } catch (final IOException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to print the output.", e);
            }
            return new ByteArrayOutputStream();
        }
    }

    public static OutputStream getXContentOutputStream(final ToXContent xContent, final MediaType mediaType) {

        response.setContentType(buf.toString());
        writeHeaders(response);
        try (PrintWriter out = new PrintWriter(new OutputStreamWriter(response.getOutputStream(), enc))) {
            out.print(text);
        } catch (final IOException e) {
            throw new IORuntimeException(e);
        }
    }

    protected abstract void writeHeaders(final HttpServletResponse response);

                        .filter(StringUtil::isNotBlank).orElse("-"));
        log(valueMap);
    }

    public void print(final String action, final OptionalThing<FessUserBean> user, final Map<String, String> params) {
        final Map<String, String> valueMap = new LinkedHashMap<>();