throw new SuggestIndexException("Failed to index from query_string.", e);
        }
    }

    // TODO replace queryLogReader with lambda reader
    public Deferred<SuggestIndexResponse>.Promise indexFromQueryLog(final QueryLogReader queryLogReader, final int docPerReq,
            final long requestInterval) {
        final Deferred<SuggestIndexResponse> deferred = new Deferred<>();

        SuggestSettings settings = suggester.settings();
        String field = settings.array().get(SuggestSettings.DefaultKeys.SUPPORTED_FIELDS)[0];

        final QueryLogReader reader = new QueryLogReader() {
            AtomicInteger count = new AtomicInteger();
            String[] queryLogs = new String[] { field + ":検索", field + ":fess", field + ":検索エンジン" };

            @Override