/**
* Returns the index for the specified edge. Calculates the indices for <code>e</code> and for all
* edges parallel to <code>e</code>.
*/
public int getIndex(Graph<V, E> graph, E e) {
Integer index = edge_index.get(e);
if (index == null) {
Pair<V> endpoints = graph.getEndpoints(e);
V u = endpoints.getFirst();
V v = endpoints.getSecond();
if (u.equals(v)) {
index = getIndex(graph, e, v);
} else {
index = getIndex(graph, e, u, v);
}
}
return index.intValue();
}
/**
* Resets the indices for this edge and its parallel edges. Should be invoked when an edge
* parallel to <code>e</code> has been added or removed.
*
* @param e
*/
public void reset(Graph<V, E> graph, E e) {
Pair<V> endpoints = graph.getEndpoints(e);
getIndex(graph, e, endpoints.getFirst());
getIndex(graph, e, endpoints.getFirst(), endpoints.getSecond());
}