private void tryAdd(String rawLine, List<Word> data, int linenum) {
        if (rawLine == null) {
            return;
        }

        String line = rawLine.trim();

        if (line.length() < prefix.length()) {
            return;
        }

        if (!line.startsWith(prefix)) {
            return;
        }

        Word w = getWord(linenum, line);
        if (w == null) {
            return;
        }

        data.add(w);

    }