Let's now delve into the details of the implementation. For example purposes, the following code assumes the topology is running locally. We use an in-memory queue instead of a persistent queue, and a hash map as our storage mechanism. In a real production implementation, we would most likely use a durable queuing system such as Kafka and a distributed storage mechanism such as Cassandra.
We will look at each of the topologies in depth, but first, let's have a look at the data model. To simplify things, we've encapsulated the game logic and the data model into two classes: Board and GameState.
The following is a listing of the Board class:
public class Board implements Serializable {
public static final String EMPTY = ' ';
public String[][] board = { { EMPTY, EMPTY, EMPTY },
{ EMPTY, EMPTY, EMPTY }, { EMPTY, EMPTY, EMPTY } };
public List<Board> nextBoards(String player) {
List<Board> boards = new ArrayList<Board>...