private WeightedMultigraph<Vertex, LabeledWeightedEdge> step5(
WeightedMultigraph<Vertex, LabeledWeightedEdge> g4) {
logger.debug("<enter");
WeightedMultigraph<Vertex, LabeledWeightedEdge> g5 = g4;
List<Vertex> nonSteinerLeaves = new ArrayList<Vertex>();
Set<Vertex> vertexSet = g4.vertexSet();
for (Vertex vertex : vertexSet) {
if (g5.degreeOf(vertex) == 1 && steinerNodes.indexOf(vertex) == -1) {
nonSteinerLeaves.add(vertex);
}
}
Vertex source, target;
for (int i = 0; i < nonSteinerLeaves.size(); i++) {
source = nonSteinerLeaves.get(i);
do {
LabeledWeightedEdge e = g5.edgesOf(source).toArray(new LabeledWeightedEdge[0])[0];
target = this.graph.getEdgeTarget(e);
// this should not happen, but just in case of ...
if (target.equals(source)) target = e.getSource();
g5.removeVertex(source);
source = target;
} while (g5.degreeOf(source) == 1 && steinerNodes.indexOf(source) == -1);
}
logger.debug("exit>");
return g5;
}
private WeightedMultigraph<Vertex, LabeledWeightedEdge> step2(
WeightedMultigraph<Vertex, LabeledWeightedEdge> g1) {
logger.debug("<enter");
KruskalMinimumSpanningTree<Vertex, LabeledWeightedEdge> mst =
new KruskalMinimumSpanningTree<Vertex, LabeledWeightedEdge>(g1);
// System.out.println("Total MST Cost: " + mst.getSpanningTreeCost());
Set<LabeledWeightedEdge> edges = mst.getEdgeSet();
WeightedMultigraph<Vertex, LabeledWeightedEdge> g2 =
new WeightedMultigraph<Vertex, LabeledWeightedEdge>(LabeledWeightedEdge.class);
List<LabeledWeightedEdge> edgesSortedByLabel = new ArrayList<LabeledWeightedEdge>();
for (LabeledWeightedEdge e : edges) edgesSortedByLabel.add(e);
Collections.sort(edgesSortedByLabel, new EdgeComparatorByLabel());
for (LabeledWeightedEdge edge : edgesSortedByLabel) {
// //just for test, forcing to select another equal minimal spanning tree
// if (g1.getEdgeSource(edge).getLabel().equalsIgnoreCase("v1") &&
// g1.getEdgeTarget(edge).getLabel().equalsIgnoreCase("v3") ) {
// Vertex v2 = steinerNodes.get(1);
// g2.addVertex(g1.getEdgeTarget(edge));
// g2.addVertex(v2);
// LabeledWeightedEdge e = new LabeledWeightedEdge("e");
// g2.setEdgeWeight(e, g1.getEdgeWeight(edge));
// g2.addEdge(g1.getEdgeTarget(edge), v2, e);
// } else
{
g2.addVertex(edge.getSource());
g2.addVertex(edge.getTarget());
g2.addEdge(edge.getSource(), edge.getTarget(), edge);
}
}
logger.debug("exit>");
return g2;
}
private WeightedMultigraph<Vertex, LabeledWeightedEdge> step3(
WeightedMultigraph<Vertex, LabeledWeightedEdge> g2) {
logger.debug("<enter");
WeightedMultigraph<Vertex, LabeledWeightedEdge> g3 =
new WeightedMultigraph<Vertex, LabeledWeightedEdge>(LabeledWeightedEdge.class);
Set<LabeledWeightedEdge> edges = g2.edgeSet();
DijkstraShortestPath<Vertex, LabeledWeightedEdge> path;
Vertex source, target;
for (LabeledWeightedEdge edge : edges) {
source = edge.getSource();
target = edge.getTarget();
path = new DijkstraShortestPath<Vertex, LabeledWeightedEdge>(this.graph, source, target);
List<LabeledWeightedEdge> pathEdges = path.getPathEdgeList();
if (pathEdges == null) continue;
for (int i = 0; i < pathEdges.size(); i++) {
if (g3.edgeSet().contains(pathEdges.get(i))) continue;
source = pathEdges.get(i).getSource();
target = pathEdges.get(i).getTarget();
if (!g3.vertexSet().contains(source)) g3.addVertex(source);
if (!g3.vertexSet().contains(target)) g3.addVertex(target);
g3.addEdge(source, target, pathEdges.get(i));
}
}
logger.debug("exit>");
return g3;
}
