Graphs - CSV to Graphviz (for dot.exe)

package graphCSV2dot;

import java.util.*;
import java.io.*;

class Road {
    int cityId;
    double lenght;

    public Road(int cityId, double lenght) {
        this.cityId = cityId;
        this.lenght = lenght;
    }
}

class City {
    int id;
    String name;
    LinkedList<Road> roads;
    HashMap<Integer, Double> roadId2Len;

    public City(int id, String name) {
        this.id = id;
        this.name = name;
        roads = new LinkedList<Road>();
        roadId2Len = new HashMap<>();
    }

    public void addRoad(int cityId, double len) {
        roads.add(new Road(cityId, len));
        roadId2Len.put(cityId, len);
    }
}

public class Main {

    public static void main(String[] args) {
        String fileName="map.csv", dotExe="c:/Programs/graphviz-2.38/bin/dot.exe";
        if (args.length<1) {
            System.err.println("Missing argument #1 - input file name. Trying "+fileName);
        } else fileName=args[0];
        if (args.length<2) {
            System.err.println("Missing argument #2 - dot.exe (full path). Trying "+dotExe);
        } else dotExe=args[1];

        System.err.println("Reading input CSV from: "+fileName);
        Scanner s;
        HashMap<Integer, City> citiesMap = new HashMap<>();
        LinkedList<City> cities = new LinkedList<>();
        try {
            s = new Scanner(new File(fileName), "utf-8");
            String outputFileName=fileName+".gv";
            PrintWriter f = new PrintWriter(outputFileName, "utf-8");
            f.print("strict digraph graphname {\n"
//                  + " concentrate=true\n"
                    + " label=\"Generated at " + new Date().toString() + "\"\n" + " overlap=false\n"
//                  + " ratio=compress\n"
//                  + " splines=true\n"
                    + " layout=sfdp\n"
//                  + " esep = -0.4\n"
//                  + " graph [pad=\"0.1\", nodesep=\"0.2\", ranksep=\"1\"];"
                    + " charset=\"UTF-8\"\n");
            while (s.hasNext()) {
                String line = s.nextLine();
                String fields[] = line.split(";");
                if (fields.length >= 2) {
                    int cityId = Integer.parseInt(fields[0]);
                    City c = new City(cityId, fields[1]);
                    f.printf("  %d [label=\"%s\"]\n", cityId, fields[1] + "\\nID=" + cityId);
                    int i;
                    for (i = 2; i < fields.length; i += 2) {
                        int cid = Integer.parseInt(fields[i + 1]);
                        double len = Double.parseDouble(fields[i]);
                        if (len == 0)
                            break;
                        c.addRoad(cid, len);
                    }
                    System.out.printf("Adding city: %s (id=%d) with %d roads.\n", c.name, c.id, i/2);
                    cities.add(c);
                    citiesMap.put(c.id, c);
                }
            }
            s.close();
            for (City c : cities) {
                for (Road r : c.roads) {
                    City dstCity = citiesMap.get(r.cityId);
                    if (dstCity == null)
                        System.err.printf("Destination city %d of road from %s with %d km does not exist\n", r.cityId,
                                c.name, r.lenght);
                    else {
                        // check the road back:
                        Double lenBack = dstCity.roadId2Len.get(c.id);
                        // if road back has different length, print the edge:
                        if (lenBack == null || lenBack != null && r.lenght != lenBack) {
                            System.err.printf("Asymetric road between city ID %d and %d\n", c.id, dstCity.id);
                            f.printf("  %d -> %d [label=\"%.0f km\"];\n", c.id, r.cityId, r.lenght);
                        } else if (c.id < dstCity.id) { // print the current road only once:
                            f.printf("  %d -> %d [label=\"%.0f km\" dir=both]\n", c.id, r.cityId, r.lenght);
                        }
                    }
                }
            }
            f.printf("}\n");
            f.close();
            Runtime.getRuntime().exec(dotExe + " -O -Tsvg "+outputFileName);
            System.out.println("OK, successfuly generated "+outputFileName+" and "+outputFileName+".svg!");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}