/**
 * Edge.java
 *
 *
 * Created: Fri Mar 31 09:31:36 2000
 *
 * @author Hans Kyndesgaard
 * @version 1
 */

public class Edge  {
    Node from;
    Node to;
    Locator fromLocator;
    Locator toLocator;

    /** Creates an edge from the <code>from</code>-node to the <code>to</code>-node.
	Even though the two nodes are adjacent an edge will be made
	between them.  O(1).
	@param from The origin of the newly created edge.
	@param to The destination of the newly created edge.
    */
    public Edge(Node from, Node to) {
	this.from = from;
	this.to = to;
	fromLocator = from.out.insertLast(this);
	toLocator = to.in.insertLast(this);
    }
    
    /** Removes <code>this</code> edge. The data structures int the nodes are updated accordingly. O(1).
     */
    public void remove(){
	from.out.remove(fromLocator);
	to.in.remove(toLocator);
    }
    
    /** Produce a stringrepresentation of a edge. This is just a pair of node representations. (O(1).)
     */
    public String toString(){
	return "(" + from + ", " + to + ")";
    }

} // Edge