public interface Converter {

    /**
     * 値を文字列として返します。
     *
     * @param value
     *            値
     * @return 文字列としての値
     */
    String getAsString(Object value);

    /**
     * 値をオブジェクトとして返します。
     *
     * @param value
     *            値
     * @return オブジェクトとしての値
     */
    Object getAsObject(String value);

    /**
     * このコンバータの変換対象なら{@literal true}を返します。
     *

    protected String[] toStringArray(final Object value) {
        if (value instanceof String[]) {
            return (String[]) value;
        } else if (value instanceof List) {
            return ((List<?>) value).stream().map(v -> v.toString()).toArray(n -> new String[n]);
        }
        String str = DfTypeUtil.toString(value);
        if (str == null) {
            return null;
        }

    }

    @Override
    public Integer getTimeToLive() {
        String value = getHandlerParameterMap().get("time_to_live");
        if (StringUtil.isBlank(value)) {
            value = getHandlerParameterMap().get("timeToLive"); // TODO remove
            if (StringUtil.isBlank(value)) {
                return null;
            }

    private SystemUtil() {
    }

    @SuppressWarnings("deprecation")
    public static String getSearchEngineHttpAddress() {
        final String value = System.getProperty(Constants.FESS_SEARCH_ENGINE_HTTP_ADDRESS);
        if (value != null) {
            return value;
        }
        return System.getProperty(Constants.FESS_ES_HTTP_ADDRESS);
    }

                    final String[] values = paramEntry.getValue();
                    if (values == null) {
                        continue;
                    }
                    final String key = paramEntry.getKey();
                    for (final String value : values) {
                        if (append) {
                            locationBuf.append('&');

    }

    @SafeVarargs
    public static <T> StreamOf<T> stream(final T... values) {
        return new StreamOf<>(() -> values != null ? Arrays.stream(values) : Collections.<T> emptyList().stream());
    }

    public static StreamOf<String> split(final String value, final String regex) {
        return stream(value == null ? null : value.split(regex));
    }

    //                                                                        ============
    protected String convertEmptyToNull(String value) {
        return (value != null && value.length() == 0) ? null : value;
    }

    // ===================================================================================

        if (StringUtil.isBlank(value)) {
            return Collections.emptyList();
        }
        return split(value, ",").get(stream -> stream.map(String::trim)//
                .map(s -> clientRuleCache.computeIfAbsent(s, t -> {
                    final String[] values = t.split(":", 2);
                    if (values.length != 2) {
                        return null;

ery\":\"NONE\",\"boost\":0.5}}},{\"match_phrase\":{\"content\":{\"query\":\"xxx:aaa\",\"slop\":0,\"zero_terms_query\":\"NONE\",\"boost\":0.05}}},{\"fuzzy\":{\"title\":{\"value\":\"xxx:aaa\",\"fuzziness\":\"AUTO\",\"prefix_length\":0,\"max_expansions\":10,\"transpositions\":true,\"boost\":0.01}}},{\"fuzzy\":{\"content\":{\"value\":\"xxx:aaa\",\"fuzziness\":\"AUTO\",\"prefix_length\":0,\"max_expansions\":10,\"transpositions\":true,\"boost\":0.005}}}],\"adjust_pure_negative\":true,\"boost\":1.0}}",...

        String hash;
        if (StringUtil.isNotBlank(form.hash)) {
            final String value = URLUtil.decode(form.hash, Constants.UTF_8);
            if (targetUrl.indexOf('#') == -1) {
                final StringBuilder buf = new StringBuilder(value.length() + 100);
                for (final char c : value.toCharArray()) {
                    if (CharUtil.isUrlChar(c) || c == ' ') {
                        buf.append(c);