package horstmann.ch08_graphed;
import java.awt.Graphics2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;

/**
   A class that supplies convenience implementations for
   a number of methods in the Edge interface type.
 */
@SuppressWarnings("serial")
public abstract class AbstractEdge implements Edge
{
  public Object clone()
  {
    try
    {
      return super.clone();
    }
    catch (CloneNotSupportedException exception)
    {
      return null;
    }
  }

  public void connect(Node s, Node e)
  {
    start = s;
    end = e;
  }

  public Node getStart()
  {
    return start;
  }

  public Node getEnd()
  {
    return end;
  }

  public Rectangle2D getBounds(Graphics2D g2)
  {
    Line2D conn = getConnectionPoints();
    Rectangle2D r = new Rectangle2D.Double();
    r.setFrameFromDiagonal(conn.getX1(), conn.getY1(),
        conn.getX2(), conn.getY2());
    return r;
  }

  public Line2D getConnectionPoints()
  {
    Rectangle2D startBounds = start.getBounds();
    Rectangle2D endBounds = end.getBounds();
    Point2D startCenter = new Point2D.Double(
        startBounds.getCenterX(), startBounds.getCenterY());
    Point2D endCenter = new Point2D.Double(
        endBounds.getCenterX(), endBounds.getCenterY());
    return new Line2D.Double(
        start.getConnectionPoint(endCenter),
        end.getConnectionPoint(startCenter));
  }

  private Node start;
  private Node end;
}