public void setGridletFinishedSoFar(double length)
    {
        // if length is -ve then ignore
        if (length < 0.0 || index_ < 0) {
            return;
        }

        Resource res = resList_.get(index_);
        res.finishedSoFar = length;

        if (record_) {
            write("Sets the length's finished so far to " + length);
        }
    }