3. The domain model

Setting the stage

We wanted to outline the domain model before diving into library details. We also looked at the data model of the themoviedb.org data to confirm that it matched our expectations.

In Java code this looks pretty straightforward:

Example 3.1. Domain model

class Movie {
    String id;
    String title;
    int year;
    Set<Role> cast;

class Actor {
    String id;
    String name;
    Set<Movie> filmography;
    Role playedIn(Movie movie, String role) { ... }

class Role {
    Movie movie;
    Actor actor;
    String role;

class User {
    String login;
    String name;
    String password;
    Set<Rating> ratings;
    Set<User> friends;
    Rating rate(Movie movie, int stars, String comment) { ... }
    void befriend(User user) { ... }

class Rating {
    User user;
    Movie movie;
    int stars;
    String comment;

Then we wrote some simple tests to show that the basic design of the domain is good enough so far. Just creating a movie, populating it with actors, and allowing users to rate it.