Actor Network Semantics

The Kevin Bacon game: given any two actors, find the shortest chain of shared-film connections between them.

Bacon reads three pipe-delimited files — actors.txt and movies.txt map numeric codes to names, and movie-actors.txt pairs each movie with its cast — and builds a graphGraph<String, HashSet<String>>, backed by an AdjacencyMapGraph. Actors are the vertices; two actors who shared a film get an undirected edge whose label is the HashSet of movies they appeared in together.

To answer a query, GraphLib.bfs re-centers the whole network on a chosen actor: breadth-first search from that center records every reachable actor's parent, producing a shortest-path tree rooted at the center. getPath then walks the parent edges from any actor back to the root, naming the linking film at each step, while getSeparation and averageSeparation measure distances within the tree. The interactive loop exposes this directly: u <name> makes an actor the center, p <name> prints a path to them, and the c, d, s, and i commands rank actors by average separation, by degree, by distance, or list those with no connection at all.