TCP Group Chat — Client

JavaFX client for a real-time group chat application over TCP sockets. It connects to the central server, sends messages typed by the user, and displays everything broadcast by the server in real time.

This is the client half of the project. The server lives in the companion TCP_Server repository.

Features (mapped to requirements)

Requirement	Where it lives
Enter a username before chatting	ClientApp.askUsername (login dialog)
Read-only mode if no username given	ClientApp readOnly flag → input controls disabled
Send via SEND button or Enter	sendButton.setOnAction + messageField.setOnAction
allUsers command lists active clients	typed in the field, sent to server
end / bye disconnects	ClientApp.handleSend → ChatClient.disconnect
"Online" status label + visual indicator (circle)	statusLabel + indicator (Circle)
Config (IP/port) from file, args override	ClientConfig (args → client.properties → default)
Model/View separation	model package has zero JavaFX imports; View talks to Model only via ClientListener

Architecture

            view (JavaFX)                     model (pure Java, no JavaFX)
   ┌─────────────────────────┐        ┌──────────────────────────────────────┐
   │ Launcher → ClientApp     │        │ ClientConfig   (args + client.properties)│
   │ implements ClientListener│◀──────▶│ ChatClient     (socket, reader thread)  │
   │  - chat TextArea         │  calls │ ClientListener (interface = boundary)   │
   │  - input + SEND button   │  back  │                                         │
   │  - Online circle + label │        │                                         │
   └─────────────────────────┘        └──────────────────────────────────────┘

The Model never imports JavaFX. ChatClient runs a background reader thread and reports incoming lines / connection events through the ClientListener interface; ClientApp implements it and hops onto the JavaFX thread with Platform.runLater.

Configuration & command-line arguments

Per requirement 4.1 the client is started with the server address and port:

java TCPClient <ServerIPAddress> <PortNumber>     # e.g. localhost 3000

Resolution order for each value: command-line argument → client.properties → built-in default.

src/main/resources/client.properties:

server.host=localhost
server.port=3000

Build & Run

Requirements: JDK 23+ and Maven.

# Run directly during development (uses client.properties defaults)
mvn clean javafx:run

# Or build the standalone executable JAR
mvn clean package
java -jar target/TCPClient.jar localhost 3000

On launch a dialog asks for a username. Leave it blank (or press Cancel) to join in READ-ONLY mode: you'll receive messages but the input box and SEND button are disabled.

mvn package produces target/TCPClient.jar — a self-contained JAR launched via org.booking.client.view.Launcher.

Wire protocol (UTF-8, line-based)

1. First line sent = username (empty ⇒ read-only).
2. Then each line is a chat message or a command (allUsers, end, bye).
3. Lines received from the server are appended verbatim to the chat area; chat messages arrive as [HH:mm:ss] username: message.

Project layout

src/main/java/org/booking/client/
  model/  ClientConfig, ClientListener, ChatClient
  view/   Launcher, ClientApp
src/main/resources/
  client.properties, client.css