org.jgrapht.alg.shortestpath.ListMultiObjectiveSingleSourcePathsImpl Maven / Gradle / Ivy
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/*
* (C) Copyright 2017-2023, by Dimitrios Michail and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* See the CONTRIBUTORS.md file distributed with this work for additional
* information regarding copyright ownership.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the
* GNU Lesser General Public License v2.1 or later
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
*
* SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
*/
package org.jgrapht.alg.shortestpath;
import org.jgrapht.*;
import org.jgrapht.alg.interfaces.MultiObjectiveShortestPathAlgorithm.*;
import org.jgrapht.graph.*;
import java.io.*;
import java.util.*;
/**
* An implementation of {@link MultiObjectiveSingleSourcePaths} which stores one list of paths per
* vertex.
*
* @author Dimitrios Michail
*
* @param the graph vertex type
* @param the graph edge type
*/
public class ListMultiObjectiveSingleSourcePathsImpl
implements MultiObjectiveSingleSourcePaths, Serializable
{
private static final long serialVersionUID = -6213225353391554721L;
/**
* The graph
*/
protected Graph graph;
/**
* The source vertex of all paths
*/
protected V source;
/**
* One path per vertex
*/
protected Map>> paths;
/**
* Construct a new instance.
*
* @param graph the graph
* @param source the source vertex
* @param paths a list of paths per target vertex
*/
public ListMultiObjectiveSingleSourcePathsImpl(
Graph graph, V source, Map>> paths)
{
this.graph = Objects.requireNonNull(graph, "Graph is null");
this.source = Objects.requireNonNull(source, "Source vertex is null");
this.paths = Objects.requireNonNull(paths, "Paths are null");
}
@Override
public Graph getGraph()
{
return graph;
}
@Override
public V getSourceVertex()
{
return source;
}
@Override
public List> getPaths(V targetVertex)
{
List> p = paths.get(targetVertex);
if (p == null) {
if (source.equals(targetVertex)) {
return Collections.singletonList(GraphWalk.singletonWalk(graph, source, 0d));
} else {
return Collections.emptyList();
}
} else {
return p;
}
}
}