code: public void setOutputDirectory (final File value)
    {
      if (value != null && !value.isAbsolute ())
      {
        throw new IllegalArgumentException ("path is not absolute: " + value);
      }
      this.outputDirectory = value;
    }
docs: Sets the absolute path to the output directory for the generated grammar
  file.
  
  @param value
  The absolute path to the output directory for the generated grammar
  file. If this directory does not exist yet, it is created. Note that
  this path should already include the desired package hierarchy
  because JTB will not append the required sub directories
  automatically.