private static List<Integer> doTopologicalSort(Graph<Coordinate, Street> g) {
final GraphHandler<Coordinate, Street> handler = new GraphHandler<Coordinate, Street>(g, true);
GraphSearchProcessor gsp =
new GraphSearchProcessor<Coordinate, Street>() {
Stack<Integer> stack = new Stack();
boolean foundCycle = false;
@Override
public void processVertexEarly(Graph<Coordinate, Street> graph, int vID) {}
@Override
public void processEdge(
Graph<Coordinate, Street> graph, int eID, int vIDfrom, int vIDto) {
if (handler.getVertexState(vIDto) == GraphHandler.DiscoverState.DISCOVERED) {
// We have found a cycle and need to abort!
handler.stopSearch();
foundCycle = true;
}
}
@Override
public void processVertexLate(Graph<Coordinate, Street> graph, int vID) {
stack.push(vID);
}
@Override
public Object getResults() {
ArrayList<Integer> topSortOrder = new ArrayList<Integer>();
if (foundCycle) return topSortOrder;
while (!stack.isEmpty()) topSortOrder.add(stack.pop());
return topSortOrder;
}
};
handler.addGraphSearchProcessor(gsp);
handler.doExhaustiveDFS();
ArrayList<Integer> ret = (ArrayList<Integer>) gsp.getResults();
return ret;
}
