package Util;

/* Edge *****************/

public class Edge {
  protected GraphNode target;
  protected GraphNode source;

  protected String dotnodeparams = new String();

  public Edge(GraphNode target) {
    this.target = target;
  }

  public String getLabel() {
    return "";
  }

  public void setSource(GraphNode s) {
    this.source=s;
  }

  public GraphNode getSource() {
    return source;
  }

  public GraphNode getTarget() {
    return target;
  }

  public void setDotNodeParameters(String param) {
    if (param == null) {
      throw new NullPointerException();
    }
    if (dotnodeparams.length() > 0) {
      dotnodeparams += "," + param;
    } else {
      dotnodeparams = param;
    }
  }

  public static final EdgeStatus UNVISITED = new EdgeStatus("UNVISITED");
  public static final EdgeStatus PROCESSING = new EdgeStatus("PROCESSING");
  public static final EdgeStatus FINISHED = new EdgeStatus("FINISHED");

  public static class EdgeStatus {
    private static String name;
    private EdgeStatus(String name) {
      this.name = name;
    }
    public String toString() {
      return name;
    }
  }

  int discoverytime = -1;
  int finishingtime = -1;   /* used for searches */
  EdgeStatus status = UNVISITED;

  void reset() {
    discoverytime = -1;
    finishingtime = -1;
    status = UNVISITED;
  }

  void discover(int time) {
    discoverytime = time;
    status = PROCESSING;
  }

  void finish(int time) {
    assert status == PROCESSING;
    finishingtime = time;
    status = FINISHED;
  }
}