code: public static String toDot(FSA fsa, int node) {
      try {
        StringWriter w = new StringWriter();
        toDot(w, fsa, node);
        return w.toString();
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    }
docs: Returns the right-language reachable from a given FSA node, formatted as an
  input for the graphviz package (expressed in the <code>dot</code>
  language).
  
  @param fsa The automaton to visualize.
  @param node Starting node (subgraph will be visualized unless it's the automaton's root node).
  @return Returns the dot language description of the automaton.