private void ensureCapacity (int n)    {
        if (n <= 0) {
            return;
        }
        int max;
        if (data == null || data.length == 0) {
            max = 25;
        }
        else if (data.length >= n * 5) {
            return;
        }
        else {
            max = data.length;
        }
        while (max < n * 5) {
            max *= 2;
        }

        String newData[] = new String[max];
        if (length > 0) {
            System.arraycopy(data, 0, newData, 0, length*5);
        }
        data = newData;
    }