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;
}