private SimpleGraph<Integer, DefaultEdge> buildGraphForTestDisconnected(int size) {
SimpleGraph<Integer, DefaultEdge> graph = new SimpleGraph<>(DefaultEdge.class);
VertexFactory<Integer> vertexFactory = new IntegerVertexFactory();
CompleteGraphGenerator<Integer, DefaultEdge> completeGraphGenerator =
new CompleteGraphGenerator<>(size);
// two complete graphs
SimpleGraph<Integer, DefaultEdge> east = new SimpleGraph<>(DefaultEdge.class);
completeGraphGenerator.generateGraph(east, vertexFactory, null);
SimpleGraph<Integer, DefaultEdge> west = new SimpleGraph<>(DefaultEdge.class);
completeGraphGenerator.generateGraph(west, vertexFactory, null);
Graphs.addGraph(graph, east);
Graphs.addGraph(graph, west);
// connected by single edge
graph.addEdge(size - 1, size);
return graph;
}
/**
* Testing a graph where the validator denies the request to go on an edge which cutting it makes
* the graph disconnected
*/
public void testDisconnected() {
int cliqueSize = 5;
// generate graph of two cliques connected by single edge
SimpleGraph<Integer, DefaultEdge> graph = buildGraphForTestDisconnected(cliqueSize);
for (int i = 0; i < graph.vertexSet().size(); i++) {
KShortestPaths<Integer, DefaultEdge> ksp =
new KShortestPaths<Integer, DefaultEdge>(
graph,
i,
100,
Integer.MAX_VALUE,
new PathValidator<Integer, DefaultEdge>() {
@Override
public boolean isValidPath(
AbstractPathElement<Integer, DefaultEdge> prevPathElement, DefaultEdge edge) {
// accept all requests but the one to pass through the edge connecting
// the two cliques.
DefaultEdge connectingEdge = graph.getEdge(cliqueSize - 1, cliqueSize);
return connectingEdge != edge;
}
});
for (int j = 0; j < graph.vertexSet().size(); j++) {
if (j == i) {
continue;
}
List<GraphPath<Integer, DefaultEdge>> paths = ksp.getPaths(j);
if ((i < cliqueSize && j < cliqueSize) || (i >= cliqueSize && j >= cliqueSize)) {
// within the clique - path should exist
assertNotNull(paths);
assertTrue(paths.size() > 0);
} else {
// else - should not
assertNull(paths);
}
}
}
}
