/**
 * A simple placeholder for Arc data
 *
 * Copyright © World Wide Web Consortium, (Massachusetts Institute of
 * Technology, Institut National de Recherche en Informatique et en
 * Automatique, Keio University).
 *
 * All Rights Reserved.
 *
 * Please see the full Copyright clause at
 * <http://www.w3.org/Consortium/Legal/copyright-software.html>
 *
 * $Log: Arc.java,v $
 * Revision 1.1  1999/01/13 15:00:17  jsaarela
 * Finished conformance testing with PR-rdf-syntax-19990105 version
 * of the RDF M&S spec.
 *
 *
 * @author	Janne Saarela <jsaarela@w3.org>
 */
package org.w3c.rdf;

import java.awt.Point;
import java.awt.Color;

public class Arc {
    private String	m_sRelation = null;
    private Point	m_start = null;
    private Point	m_end = null;
    private Point	m_middle = null;
    private Color	m_color = Color.black;
    private Node	m_startNode = null;
    private Node	m_endNode = null;

    static public boolean	SHORTNAMES = true;

    public static final Color DEFAULT_COLOR = Color.black;
    public static final Color SELECTED_COLOR = Color.green;

    public Arc (String sRelation,
		Point start,
		Point end,
		Node startNode,
		Node endNode) {
	m_sRelation = sRelation;
	m_start = start;
	m_end = end;
	m_middle = new Point ((start.x+end.x)/2, (start.y+end.y)/2);
	m_startNode = startNode;
	m_endNode = endNode;
    }

    public Point start () {
	return m_start;
    }

    public Point end () {
	return m_end;
    }

    public String visualRelation() {
	if (SHORTNAMES) {
	    int iHashIndex = m_sRelation.lastIndexOf('#');
	    if (iHashIndex > -1)
		return m_sRelation.substring (iHashIndex+1);
	    else
		return m_sRelation;
	} else {
	    return m_sRelation;
	}
    }

    public String relation() {
	return m_sRelation;
    }

    /**
     * Return the distance of the point <i>p</i> from the middle
     * point of the Arc (Do not take square root for efficiency)
     */
    public double distance (Point p) {
	int dx = m_middle.x - p.x;
	int dy = m_middle.y - p.y;
	return dx*dx + dy*dy;
    }

    public Color color () {
	return m_color;
    }
    
    public void setColor (Color c) {
	m_color = c;
    }
}