Problems getting an object from hashmap

[trask]

hi,

I am troubled by a small problem. I am now using a graph metod which uses edge to connect various places in a map. So i created a hashmap which takes in String
and an arraylist (edge) which states the destinations from that string along with the travel time.

But how to find connections between two places?

t.ex, a to b takes 15mins by buss , b to c takes 10mins by train,
so if i want to find connection between a to c, it should show me exactly that and the total time.

To add new places and to connect them works. Only to find connections is the problem..

Thanks in forehand

pasting the java codes.

class PlaceGraph<N> implements Graph <N> {
 
    private Map<N, List<Edge<N>>> allp = new HashMap <N, List<Edge<N>>>();
 
 
    public void addNode(N node){
    if (!allp.containsKey(node))
        allp.put(node, new ArrayList<Edge<N>>());
    else 
        System.out.println ("Same name found");
    }
 
 
    public void connect (N from, N to, String med, int traveltime){
 
    List<Edge<N>> flist = allp.get(from);
    List<Edge<N>> tlist = allp.get(to);
 
    if (flist == null || tlist ==null)
        throw new NoSuchElementException();
    if (traveltime<0)
        throw new IllegalArgumentException();
 
 
    Edge<N> e1 = new Edge<N> (to, med, traveltime);
    flist.add(e1);
    Edge<N> e2 = new Edge<N> (from, med, traveltime);
    tlist.add(e2);
    }
 
 
    PROBLEM HERE/public void find(N b, N d){
 
    }
 
      public String toString(){
      String str = " ";
    for (Map.Entry<N, List<Edge<N>>> p : allp.entrySet()){
        str+=p.getKey() + " : ";
        for (Edge e : p.getValue())
        str += e.toString()+ " ";
        str += "\n";
    }
    return str ;
      }
}
 
//Edge class contains three variables. Destination, medium of travel and traveltime.