ShortestPathTestCase.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 program and the accompanying materials are dual-licensed under
 * either
 *
 * (a) the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation, or (at your option) any
 * later version.
 *
 * or (per the licensee's choosing)
 *
 * (b) the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation.
 */
/* ------------------------------
 * ShortestPathTestCase.java
 * ------------------------------
 * (C) Copyright 2003-2008, by John V. Sichi and Contributors.
 *
 * Original Author:  John V. Sichi
 * Contributor(s):   -
 *
 * $Id$
 *
 * Changes
 * -------
 * 14-Jan-2006 : Factored out of DijkstraShortestPathTest (JVS);
 *
 */
package org.jgrapht.alg;

import java.util.*;

import junit.framework.*;

import org.jgrapht.*;
import org.jgrapht.graph.*;


/**
 * .
 *
 * @author John V. Sichi
 */
public abstract class ShortestPathTestCase
    extends TestCase
{
    //~ Static fields/initializers ---------------------------------------------

    static final String V1 = "v1";
    static final String V2 = "v2";
    static final String V3 = "v3";
    static final String V4 = "v4";
    static final String V5 = "v5";

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

    DefaultWeightedEdge e12;
    DefaultWeightedEdge e13;
    DefaultWeightedEdge e15;
    DefaultWeightedEdge e24;
    DefaultWeightedEdge e34;
    DefaultWeightedEdge e45;

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

    /**
     * .
     */
    public void testPathBetween()
    {
        List path;
        Graph<String, DefaultWeightedEdge> g = create();

        path = findPathBetween(g, V1, V2);
        assertEquals(Arrays.asList(new DefaultEdge[] { e12 }), path);

        path = findPathBetween(g, V1, V4);
        assertEquals(Arrays.asList(
                new DefaultEdge[] {
                    e12,
                    e24
                }), path);

        path = findPathBetween(g, V1, V5);
        assertEquals(Arrays.asList(
                new DefaultEdge[] {
                    e12,
                    e24,
                    e45
                }), path);

        path = findPathBetween(g, V3, V4);
        assertEquals(Arrays.asList(
                new DefaultEdge[] {
                    e13,
                    e12,
                    e24
                }), path);
    }

    protected abstract List findPathBetween(
        Graph<String, DefaultWeightedEdge> g,
        String src,
        String dest);

    protected Graph<String, DefaultWeightedEdge> create()
    {
        return createWithBias(false);
    }

    protected Graph<String, DefaultWeightedEdge> createWithBias(
        boolean negate)
    {
        Graph<String, DefaultWeightedEdge> g;
        double bias = 1;
        if (negate) {
            // negative-weight edges are being tested, so only a directed graph
            // makes sense
            g = new SimpleDirectedWeightedGraph<String, DefaultWeightedEdge>(
                DefaultWeightedEdge.class);
            bias = -1;
        } else {
            // by default, use an undirected graph
            g = new SimpleWeightedGraph<String, DefaultWeightedEdge>(
                DefaultWeightedEdge.class);
        }

        g.addVertex(V1);
        g.addVertex(V2);
        g.addVertex(V3);
        g.addVertex(V4);
        g.addVertex(V5);

        e12 = Graphs.addEdge(g, V1, V2, bias * 2);

        e13 = Graphs.addEdge(g, V1, V3, bias * 3);

        e24 = Graphs.addEdge(g, V2, V4, bias * 5);

        e34 = Graphs.addEdge(g, V3, V4, bias * 20);

        e45 = Graphs.addEdge(g, V4, V5, bias * 5);

        e15 = Graphs.addEdge(g, V1, V5, bias * 100);

        return g;
    }
}

// End ShortestPathTestCase.java