public int getRowIndex(Comparable rowKey) {
        int result = -1;
        int count = this.data.size();
        for (int i = 0; i < count; i++) {
            TaskSeries s = (TaskSeries) this.data.get(i);
            if (s.getKey().equals(rowKey)) {
                result = i;
                break;
            }
        }
        return result;