.replaceAll(Pattern.quote("${fess.index.number_of_shards}"), numberOfShards)//
                .replaceAll(Pattern.quote("${fess.index.auto_expand_replicas}"), autoExpandReplicas);
        for (final UnaryOperator<String> rule : docSettingRewriteRuleList) {
            source = rule.apply(source);
        }
        return source;
    }

    /**

     * @param autoExpandReplicas the auto expand replicas setting for the new index
     * @return true if the reindex operation started successfully, false otherwise
     */
    protected boolean startReindex(final boolean replaceAliases, final boolean resetDictionaries, final String numberOfShards,
            final String autoExpandReplicas) {
        final String docIndex = "fess";