org.jgrapht.generate.CompleteGraphGenerator Maven / Gradle / Ivy
/*
* (C) Copyright 2003-2018, by Tim Shearouse and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* 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.
*/
package org.jgrapht.generate;
import org.jgrapht.*;
import java.util.*;
/**
* Generates a complete graph of any size.
*
*
* A complete graph is a graph where every vertex shares an edge with every other vertex. If it is a
* directed graph, then edges must always exist in both directions.
*
* @param the graph vertex type
* @param the graph edge type
*
* @author Tim Shearouse
* @since Nov 02, 2008
*/
public class CompleteGraphGenerator
implements
GraphGenerator
{
private int size;
/**
* Construct a new CompleteGraphGenerator.
*
* @param size number of vertices to be generated
* @throws IllegalArgumentException if the specified size is negative
*/
public CompleteGraphGenerator(int size)
{
if (size < 0) {
throw new IllegalArgumentException("must be non-negative");
}
this.size = size;
}
/**
* {@inheritDoc}
*/
@Override
public void generateGraph(Graph target, Map resultMap)
{
if (size < 1) {
return;
}
/*
* Ensure directed or undirected
*/
GraphTests.requireDirectedOrUndirected(target);
boolean isDirected = target.getType().isDirected();
/*
* Add vertices
*/
List nodes = new ArrayList<>(size);
for (int i = 0; i < size; i++) {
V newVertex = target.addVertex();
if (newVertex == null) {
throw new IllegalArgumentException("Invalid vertex supplier");
}
nodes.add(newVertex);
}
/*
* Add edges
*/
for (int i = 0; i < size; i++) {
for (int j = i + 1; j < size; j++) {
V v = nodes.get(i);
V u = nodes.get(j);
target.addEdge(v, u);
if (isDirected) {
target.addEdge(u, v);
}
}
}
}
}
// End CompleteGraphGenerator.java