ClassBasedEdgeFactory.java

/* ==========================================
 * JGraphT : a free Java graph-theory library
 * ==========================================
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Creator:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2008, 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.
 */
/* ------------------
 * ClassBasedEdgeFactory.java
 * ------------------
 * (C) Copyright 2003-2008, by Barak Naveh and Contributors.
 *
 * Original Author:  Barak Naveh
 * Contributor(s):   Christian Hammer
 *
 * $Id: ClassBasedEdgeFactory.java 645 2008-09-30 19:44:48Z perfecthash $
 *
 * Changes
 * -------
 * 24-Jul-2003 : Initial revision (BN);
 * 04-Aug-2003 : Renamed from EdgeFactoryFactory & made utility class (BN);
 * 03-Nov-2003 : Made edge factories serializable (BN);
 * 11-Mar-2004 : Made generic (CH);
 * 28-May-2006 : Moved connectivity info from edge to graph (JVS);
 *
 */
package edu.nd.nina.graph;

import java.io.*;
import java.lang.reflect.Constructor;

import edu.nd.nina.*;


/**
 * An {@link EdgeFactory} for producing edges by using a class as a factory.
 *
 * @author Barak Naveh
 * @since Jul 14, 2003
 */
public class ClassBasedEdgeFactory<V, E>
    implements EdgeFactory<V, E>,
        Serializable
{
    //~ Static fields/initializers ---------------------------------------------

    private static final long serialVersionUID = 3618135658586388792L;

    //~ Instance fields --------------------------------------------------------

    private final Class<? extends E> edgeClass;

    //~ Constructors -----------------------------------------------------------

    public ClassBasedEdgeFactory()
    {
    	this.edgeClass = null;
    }
    
    public ClassBasedEdgeFactory(Class<? extends E> edgeClass)
    {
        this.edgeClass = edgeClass;
    }

    //~ Methods ----------------------------------------------------------------

    /**
     * @see EdgeFactory#createEdge(Object, Object)
     */
    public E createEdge(V source, V target)
    {
		try {
			boolean canconstruct = false;
			Constructor<?>[] cs = edgeClass.getConstructors();
			for(Constructor<?> c : cs){
				if(c.getParameterTypes().length == 2 && c.getParameterTypes()[0].isAssignableFrom(Type.class) && c.getParameterTypes()[1].isAssignableFrom(Type.class)){
					canconstruct = true;
				}
			}
			
			if (!canconstruct) {
				return edgeClass.getConstructor().newInstance();
			} else {
				return edgeClass.getConstructor(Type.class, Type.class)
						.newInstance(source, target);
			}
		} catch (Exception ex) {
			throw new RuntimeException("Edge factory failed", ex);
		}
    }
}

// End ClassBasedEdgeFactory.java