Java Movie CLI

What I built

I built a single-file Java console application called Movies.java. It defines a movie record, loads data from a file when available, falls back to sample data when needed, and gives the user an interactive menu.

Program features

The app is small, but it has a complete working loop: load data, show a menu, process user input, update the movie list, and rebuild the title index when the data changes.

The menu workflow

The program runs as a terminal app. The user selects an option, the program performs the action, then returns to the menu.

=====================================
-------Welcome to the Movie DB-------
=====================================

Menu:
1.) Suggest random movies
2.) Search by Title
3.) Add Movie
4.) Remove Movie
Q.) Quit

Select Option >

Data structures used

This was the core data structures part of the project. Each structure has a clear reason.

Why ArrayList works for random suggestions

Random movie suggestions need fast indexed access. That makes ArrayList a good choice because the program can generate a random index and immediately retrieve the movie at that position.

static void showRandom(ArrayList<Movie> list, int k) {
    if (list.isEmpty()) {
        System.out.println("(No Results)");
        return;
    }

    int size = list.size();
    int n = Math.min(k, size);
    boolean[] used = new boolean[size];
    int printed = 0;

    while (printed < n) {
        int idx = (int) (Math.random() * size);

        if (used[idx]) continue;

        used[idx] = true;
        System.out.println("#" + (printed + 1) + ". " + list.get(idx));
        printed++;
    }
}

How title normalization works

Search works better when titles are normalized. The program lowercases titles and removes leading articles like the, a, and an.

static String normTitle(String s) {
    if (s == null) return "";

    s = s.trim().toLowerCase();

    if (s.startsWith("the ")) return s.substring(4).trim();
    if (s.startsWith("an "))  return s.substring(3).trim();
    if (s.startsWith("a "))   return s.substring(2).trim();

    return s;
}

How the TreeMap title index works

The title index maps a normalized title string to a list of matching movie objects. This is better than only storing titles because the program can retrieve and print the full movie record.

static Map<String, List<Movie>> buildTitleIndex(List<Movie> movies) {
    Map<String, List<Movie>> index = new TreeMap<>();

    for (Movie m : movies) {
        String key = normTitle(m.title);
        List<Movie> bucket = index.computeIfAbsent(key, k -> new ArrayList<>());
        bucket.add(m);
    }

    return index;
}

Exact search first, prefix search second

When the user searches, the program first checks for an exact normalized title match. After that, it scans the sorted keys for titles that start with the search text.

// Exact match first
List<Movie> exact = titleIndex.get(searchTitle);

if (exact != null) {
    for (Movie m : exact) {
        System.out.println(m);
    }
}

// Prefix matches second
for (Map.Entry<String, List<Movie>> entry : titleIndex.entrySet()) {
    String key = entry.getKey();

    if (!key.startsWith(searchTitle) || key.equals(searchTitle)) continue;

    for (Movie m : entry.getValue()) {
        System.out.println(m);
    }
}

Input file format

The program tries to load a file named movies_data.tsv. It expects a header row and exactly 12 tab-separated fields per movie.

String[] c = line.split("\t", -1);

if (c.length != EXPECTED_COLS) continue;

movies.add(new Movie(
    c[0], c[1], c[2], c[3], c[4], c[5],
    c[6], c[7], c[8], c[9], c[10], c[11]
));

Fallback sample data

If the TSV file is missing or no valid rows are loaded, the program falls back to a built-in sample dataset of 25 movies. That makes the project easier to demo because it still works without an external file.

ArrayList<Movie> movies = loadFile();

if (movies.isEmpty()) {
    movies = seedSample();
    System.out.println("File Not Found: Reverting to sample dataset");
} else {
    System.out.println("Loaded " + movies.size() + " movies from: movies_data.tsv");
}

Add and remove operations

Adding and removing movies changes the main ArrayList. After either operation, the program rebuilds the TreeMap title index so search results stay current.

case "3": {
    addMovie(in, movies);
    titleIndex = buildTitleIndex(movies);
    returnToMenu(in);
    break;
}

case "4": {
    removeMovieByTitle(in, movies);
    titleIndex = buildTitleIndex(movies);
    returnToMenu(in);
    break;
}

Complexity notes

The project is small, but it still shows how data-structure choices affect performance.

What I learned

This project helped connect class data-structure concepts to a working program.

Future improvements

The current version works for the assignment, but there are clear ways to make it more robust.

Run it locally

The project can be compiled and run directly with the Java compiler and runtime.

javac Movies.java
java Movies

Final idea