/**
 * Class to implement a directed edge.
 * All values associated with an edge are final.  
 * The only thing you can do is create the edge or delete the edge.
 * 
 * Note clear that I really need the <E> stuff here as it really only applies to the node.  
 * But it does not hurt, or even particularly hinder
 * 
 * @author geoffreytowell
 *
 * @param <E>
 */
public class Edge<E>
{
    private final Node<E> from;
    private final Node<E> too;
    private final String id;
    private final int cost;
    
    /**
     * Create an edge with a default cost of 1.
     * @param f
     * @param t
     * @param id
     */
    public Edge(Node<E> f, Node<E> t, String id)
    {
	this(f, t, id, 1);
    }
    
    public Edge(Node<E> f, Node<E> t, String id, int c)
    {
	from=f;
	too=t;
	this.id=id;
	this.cost = c;
    }
    public Node<E> getFrom()
    {
	return from;
    }
    public Node<E>getToo()
    {
	return too;
    }
    public int getCost()
    {
	return this.cost;
    }
    public String toString()
    {
	return String.format("<%s %s-->%s  c:%d>", this.id, from.toString(), too.toString(), cost);
    }
}