code: public void setLocation(String filename, int line) throws IOException
    {
      if (_lineMap != null && filename != null && line >= 0) {
        _lineMap.add(filename, line, _destLine, _isPreferLast);
      }
    }
docs: Sets the source filename and line.
  
  @param filename
  the filename of the source file.
  @param line
  the line of the source file.