LibraryMongoDB

A JavaFX desktop client for a MongoDB book library — the same MVC structure as the MySQL variant, rebuilt on the document model.

Built with Ahmed El Yasini as a pair project for Databasteknik at KTH.

What works

• Search by title, ISBN, author, genre, or rating. Author and genre use case-insensitive substring matching; ISBN is exact. Title uses a MongoDB text index, which matches whole words rather than substrings — searching Lor will not find The Lord of the Rings.
• Add and remove books, with multiple authors and genres per book.
• Rate a book from 1 to 10, or write a text review.
• Average rating recalculated automatically across all ratings above zero, so text-only reviews do not drag the average down.
• Accounts — register and log in; book management is disabled until you do.

Six indexes are created on the BOOKS collection at connect time: a text index on title, ascending indexes on ISBN, authors.name and genres.name, a descending index on average_rating, and a unique index on book_id.

Most database work runs on JavaFX Task threads. The initial connect and both login and registration do not — they run on the UI thread and will block the window while they wait.

Requirements

• JDK 21 — the POM targets 21.
• MongoDB running on localhost:27017.
• Maven is not required; the repository ships the Maven wrapper.

Database setup

The application connects as a MongoDB user named appUser, authenticating against the library database itself rather than admin. That user must exist before the app can connect. The connection string, including the password, is a compile-time constant in src/main/java/se/kth/awad/librarymongodb/model/BooksDbMongo.java.

Sample data lives in Database/. The files are JSON arrays, so mongoimport needs --jsonArray, and the collection names must be uppercase — the code looks for BOOKS, REVIEWS, USERS and COUNTERS, and a lowercase collection silently returns nothing.

mongoimport --db library --collection BOOKS    --jsonArray --file Database/library.BOOKS.json
mongoimport --db library --collection REVIEWS  --jsonArray --file Database/library.REVIEWS.json
mongoimport --db library --collection USERS    --jsonArray --file Database/library.USERS.json
mongoimport --db library --collection COUNTERS --jsonArray --file Database/library.COUNTERS.json

The database is named library, lowercase. The UI reports connecting to "LibraryDB", but that string is passed to a method that discards it — library is the database actually used.

MongoDB Setup/ contains screenshots of the Compass account setup. There is no written guide.

Building and running

./mvnw javafx:run      # Linux / macOS
mvnw.cmd javafx:run    # Windows

Nothing connects at startup. Use File → Connect, then log in.

Known gaps

• A user gets one review or one rating per book, ever. Ratings and text reviews are the same document and share a single uniqueness guard, so writing a review permanently blocks you from rating that book and vice versa. Trying either a second time fails with "You have already added a review for this book." There is no update path in the model — a rating can never be changed.
• An account with no stored password can be logged into with any password. If a user document has a missing, null, or empty password field, the login dialog accepts whatever you type. Passwords are also stored and compared in plaintext, and the MongoDB password is committed to the repository.
• Imported sample users show as "Unknown". The sample data writes userID while the lookup queries user_ID, so the "added by" line in book details cannot resolve any imported user. Accounts created inside the running app are unaffected.

License

MIT