net.sourceforge.plantuml.geom.Dijkstra Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of plantuml Show documentation
Show all versions of plantuml Show documentation
PlantUML is a component that allows to quickly write :
* sequence diagram,
* use case diagram,
* class diagram,
* activity diagram,
* component diagram,
* state diagram
* object diagram
/* ========================================================================
* PlantUML : a free UML diagram generator
* ========================================================================
*
* (C) Copyright 2009-2013, Arnaud Roques
*
* Project Info: http://plantuml.sourceforge.net
*
* 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.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* Original Author: Arnaud Roques
*
* Revision $Revision: 9786 $
*
*/
package net.sourceforge.plantuml.geom;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class Dijkstra {
final private double basic[][];
final private double dist[];
final private int previous[];
final private Set q = new HashSet();
final private int size;
public Dijkstra(int size) {
this.size = size;
this.basic = new double[size][size];
this.dist = new double[size];
this.previous = new int[size];
for (int i = 0; i < size; i++) {
for (int j = 0; j < size; j++) {
this.basic[i][j] = i == j ? 0 : Double.MAX_VALUE;
}
}
}
public void addLink(int n1, int n2, double d) {
// Log.println("Adding " + n1 + " " + n2 + " " + d);
if (n1 == n2) {
throw new IllegalArgumentException();
}
basic[n1][n2] = d;
basic[n2][n1] = d;
}
private void init() {
for (int i = 0; i < size; i++) {
this.dist[i] = Double.MAX_VALUE;
this.previous[i] = -1;
this.q.add(i);
}
this.dist[0] = 0;
}
private void computePrevious() {
init();
while (q.size() > 0) {
final int u = smallest();
if (dist[u] == Double.MAX_VALUE) {
return;
}
q.remove(u);
for (int v = 0; v < size; v++) {
if (basic[u][v] == Double.MAX_VALUE) {
continue;
}
final double alt = dist[u] + basic[u][v];
if (alt < dist[v]) {
dist[v] = alt;
previous[v] = u;
}
}
}
}
public List getBestPath() {
final List result = new ArrayList();
computePrevious();
int u = size - 1;
while (previous[u] >= 0) {
result.add(0, u);
u = previous[u];
}
result.add(0, 0);
return Collections.unmodifiableList(result);
}
private int smallest() {
int result = -1;
for (Integer i : q) {
if (result == -1 || dist[i] < dist[result]) {
result = i;
}
}
return result;
}
public final int getSize() {
return size;
}
}