/* ==========================================
 * JGraphT : a free Java graph-theory library
 * ==========================================
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Lead:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2004, by Barak Naveh and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
/* --------------------
 * UndirectedGraph.java
 * --------------------
 * (C) Copyright 2003, by Barak Naveh and Contributors.
 *
 * Original Author:  Barak Naveh
 * Contributor(s):   -
 *
 * $Id: UndirectedGraph.java,v 1.3 2004/05/01 23:15:46 barak_naveh Exp $
 *
 * Changes
 * -------
 * 24-Jul-2003 : Initial revision (BN);
 *
 */
package org._3pq.jgrapht;

/**
 * A graph whose all edges are undirected. This is the root interface of all
 * undirected graphs.
 * 
 * <p>
 * See <a href="http://mathworld.wolfram.com/Graph.html">
 * http://mathworld.wolfram.com/Graph.html</a> for more on undirected and on
 * directed graphs.
 * </p>
 *
 * @author Barak Naveh
 *
 * @since Jul 14, 2003
 */
public interface UndirectedGraph extends Graph {
    /**
     * Returns the degree of the specified vertex. A degree of a vertex in an
     * undirected graph is the number of edges touching that vertex.
     *
     * @param vertex vertex whose degree is to be calculated.
     *
     * @return the degree of the specified vertex.
     */
    public int degreeOf( Object vertex );
}