if (start == -1) {
            return null;
        }
        start += 3;

        final int end = entryDn.indexOf(',', start);
        final String value = end == -1 ? entryDn.substring(start) : entryDn.substring(start, end);
        if (fessConfig.isLdapGroupNameWithUnderscores()) {
            return replaceWithUnderscores(value);
        }
        return value;
    }

                final String key = entry.getKey();
                if (key.startsWith("fields.")) {
                    final String[] value = simplifyArray(entry.getValue());
                    fields.put(key.substring("fields.".length()), value);
                }
            }
            return fields;
        }

        @Override
        public Map<String, String[]> getConditions() {

        if (username == null) {
            value = StringUtil.EMPTY;
        } else if (maxLength >= 0 && username.length() > maxLength) {
            value = username.substring(0, maxLength);
        } else {
            value = username;
        }
        return String.format(getSystemProperty(Constants.LDAP_SECURITY_PRINCIPAL, StringUtil.EMPTY), value);
    }