final PingResponse pingResponse = searchEngineClient.ping();
            writeJsonResponse(pingResponse.getStatus() == 0 ? HttpServletResponse.SC_OK : HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                    "\"data\":" + pingResponse.getMessage());
        } catch (final Exception e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to process a ping request.", e);
            }

            }
        });

    }

    /**
     * Pings the search engine cluster to check connectivity and health.
     *
     * @return the ping response with cluster information
     * @throws SearchEngineClientException if the ping fails
     */
    public PingResponse ping() {
        try {
            final ClusterHealthResponse response =

# Whether to allow credentials for CORS.
api.cors.allow.credentials=true
# Whether to enable JSONP for API.
api.jsonp.enabled=false
# Fields for API ping to search engine.
api.ping.search_engine.fields=status,timed_out


# Virtual Host: Host:fess.codelibs.org=fess
virtual.host.headers=

# Hostname for the HTTP proxy server.
http.proxy.host=

     */
    boolean isApiJsonpEnabled();

    /**
     * Get the value for the key 'api.ping.search_engine.fields'. <br>
     * The value is, e.g. status,timed_out <br>
     * comment: Fields for API ping to search engine.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */