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/* ========================================================================
* PlantUML : a free UML diagram generator
* ========================================================================
*
* (C) Copyright 2009-2017, Arnaud Roques
*
* Project Info: http://plantuml.com
*
* If you like this project or if you find it useful, you can support us at:
*
* http://plantuml.com/patreon (only 1$ per month!)
* http://plantuml.com/paypal
*
* This file is part of PlantUML.
*
* PlantUML is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* PlantUML 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 General Public
* License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
*
* Original Author: Arnaud Roques
*
*
*/
package net.sourceforge.plantuml.graph2;
/*
* Copyright (c) 2009 the authors listed at the following URL, and/or the
* authors of referenced articles or incorporated external code:
* http://en.literateprograms.org/Dijkstra's_algorithm_(Java)?action=history&offset=20081113161332
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Retrieved from:
* http://en.literateprograms.org/Dijkstra's_algorithm_(Java)?oldid=15444
*/
// http://www.google.fr/search?hl=fr&source=hp&q=A+star+java&btnG=Recherche+Google&meta=&aq=f&oq=
// http://www.edenwaith.com/products/pige/tutorials/a-star.php
import java.util.ArrayList;
import java.util.List;
import java.util.PriorityQueue;
public class Dijkstra {
static class Vertex implements Comparable<Vertex> {
private final Object data;
private final List<Edge> adjacencies = new ArrayList<Edge>();
private double minDistance = Double.POSITIVE_INFINITY;
private Vertex previous;
Vertex(Object data) {
this.data = data;
}
public void addAdjacencies(Vertex target, double dist) {
if (target == null) {
throw new IllegalArgumentException();
}
adjacencies.add(new Edge(target, dist));
}
public String toString() {
return "[ " + data.toString() + " (" + minDistance + ") ] ";
}
public int compareTo(Vertex other) {
return Double.compare(minDistance, other.minDistance);
}
public final Object getData() {
return data;
}
}
static class Edge {
private final Vertex target;
private final double weight;
Edge(Vertex argTarget, double argWeight) {
target = argTarget;
weight = argWeight;
}
}
private final List<Vertex> vertices = new ArrayList<Vertex>();
public Vertex addVertex(Object data) {
final Vertex v = new Vertex(data);
vertices.add(v);
return v;
}
private void computePaths(Vertex source) {
source.minDistance = 0.;
final PriorityQueue<Vertex> vertexQueue = new PriorityQueue<Vertex>();
vertexQueue.add(source);
while (vertexQueue.isEmpty() == false) {
final Vertex u = vertexQueue.poll();
// Visit each edge exiting u
for (Edge e : u.adjacencies) {
final Vertex v = e.target;
final double weight = e.weight;
final double distanceThroughU = u.minDistance + weight;
if (distanceThroughU < v.minDistance) {
vertexQueue.remove(v);
v.minDistance = distanceThroughU;
v.previous = u;
vertexQueue.add(v);
}
}
}
}
public List<Vertex> getShortestPathTo(Vertex source, Vertex target) {
computePaths(source);
final List<Vertex> path = new ArrayList<Vertex>();
for (Vertex vertex = target; vertex != null; vertex = vertex.previous) {
path.add(0, vertex);
}
return path;
}
}
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