ChessFX

A chess application written in JavaFX. This was my semester project for TDT4100 Object-Oriented Programming at NTNU.

Features

• All moves are recorded using chess notation.
• Legal moves are highlighted when clicking a piece.
• The user can choose playing color.
• The computer always plays a random legal move.
• Pieces are automatically centered to their destination square.
• Games can be saved to disk and continued later.
• Castling is implemented, but pawn promotion and en passant are not.

GIF of gameplay (The computer doesn't always play the best move.)

Technical overview

Built with Apache Maven

Apache Maven is used to configure and run the application. This was an administrative requirement. The project is therefore built using its project object model (see pom.xml) and a set of plugins (like JavaFX, JUnit and JaCoCo).

Model-View-Controller Principle

The application is written according to the Model-View-Controller principle.

• chessfx.game is responsible for the game logic and the current state.
• chessfx.ui represents the current state in the user interface.
  • The window layout is defined in an .fxml file while a separate controller class processes user interaction.
• chessfx.persistence can save and load the games from disk.

Automated testing

Tests are written using JUnit 5 and test coverage is reported using the JaCoCo Maven Plug-In. The methods in the user interface is not tested.

Element	Missed instructions	Coverage	Missed branches	Coverage	Methods	Classes
chessfx.game	🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟥	90%	🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟥 🟥	81%	75	10
chessfx.game.pieces	🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩	98%	🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩	99%	25	6
chessfx.persistence	🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟥	94%	🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟩 🟥	85%	6	1
Total		92%		88%	106	17

Example test: Checkmate

The below test includes some given setup moves, a verification that the moves were processed correctly, and test of the game state before and after a subsequent checkmating-move (expecting the state to change from ActiveGame to BlackWin).

public class MoveTest {
    private Game game;
    private List<Move> moveList;

    @BeforeEach()
    public void setup() {
        game = new Game(true);
        game.move("e2", "e4");  // 1. e4
        game.move("e7", "e5");  // 1… e5
        game.move("g1", "f3");  // 2. Nf3
        game.move("b8", "c6");  // 2… Nc6
        game.move("f1", "c4");  // 3. Bc4
        game.move("d8", "h4");  // 3… Qh4
        game.move("d2", "d3");  // 4. d3
        game.move("g8", "f6");  // 4… Nf6
        game.move("c1", "g5");  // 5. Bg5
        game.move("f6", "g4");  // 5… Ng4
        game.move("f3", "e5");  // 6. Nxe5
        moveList = game.getMoveList();
    }

    @Test
    public void testIntegrityOfSetupFunction() {
        assertTrue(moveList.size() == 11);
        List<String> notation = Arrays.asList("e4", "e5", "Nf3", "Nc6", "Bc4", "Qh4", "d3", "Nf6", "Bg5", "Ng4", "Nxe5");
        for (int i = 0; i < 11; i++) {
            assertEquals(notation.get(i), moveList.get(i).getNotation());   // Check notation
            assertEquals((i / 2) + 1, moveList.get(i).getMoveCount());      // Check move count
        }
    }

    @Test
    public void testCheckMateQxf7() {
        assertTrue(game.getGameStatus() == GameStatus.ActiveGame);
        game.move("h4", "f2");  // 6… Qxf2#
        assertTrue(game.getGameStatus() == GameStatus.BlackWin);
    }

    // More tests
}

File structure

📦chessfx
 ┣ 📂src
 ┃ ┣ 📂main
 ┃ ┃ ┣ 📂java
 ┃ ┃ ┃ ┣ 📂chessfx
 ┃ ┃ ┃ ┃ ┣ 📂game
 ┃ ┃ ┃ ┃ ┃ ┣ 📂pieces
 ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Bishop.java
 ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜King.java
 ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Knight.java
 ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Pawn.java
 ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Queen.java
 ┃ ┃ ┃ ┃ ┃ ┃ ┗ 📜Rook.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜Board.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜Game.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜Move.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜ObservableMovePair.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜Piece.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜Square.java
 ┃ ┃ ┃ ┃ ┃ ┗ 📜ValidateMove.java
 ┃ ┃ ┃ ┃ ┣ 📂persistence
 ┃ ┃ ┃ ┃ ┃ ┣ 📜SaveLoadAgent.java
 ┃ ┃ ┃ ┃ ┃ ┗ 📜SaveLoadInterface.java
 ┃ ┃ ┃ ┃ ┗ 📂ui
 ┃ ┃ ┃ ┃ ┃ ┣ 📜BoardFX.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜ChessFXApp.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜ChessFXController.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜PieceFX.java
 ┃ ┃ ┃ ┃ ┃ ┗ 📜SquareFX.java
 ┃ ┃ ┃ ┗ 📜module-info.java
 ┃ ┃ ┗ 📂resources
 ┃ ┃ ┃ ┗ 📂chessfx
 ┃ ┃ ┃ ┃ ┗ 📂ui
 ┃ ┃ ┃ ┃ ┃ ┣ 📂pieces
 ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📂black_png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜bishop.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜king.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜knight.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜pawn.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜queen.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┗ 📜rook.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┗ 📂white_png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜bishop.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜king.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜knight.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜pawn.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜queen.png
 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┗ 📜rook.png
 ┃ ┃ ┃ ┃ ┃ ┗ 📜App.fxml
 ┃ ┗ 📂test
 ┃ ┃ ┗ 📂java
 ┃ ┃ ┃ ┗ 📂chessfx
 ┃ ┃ ┃ ┃ ┣ 📂game
 ┃ ┃ ┃ ┃ ┃ ┣ 📜BoardTest.java
 ┃ ┃ ┃ ┃ ┃ ┣ 📜MoveTest.java
 ┃ ┃ ┃ ┃ ┃ ┗ 📜SquareTest.java
 ┃ ┃ ┃ ┃ ┣ 📂persistence
 ┃ ┃ ┃ ┃ ┃ ┗ 📜SaveLoadAgentTest.java
 ┣ 📜pom.xml

Screenshots

Menu

White player perspective

Black player perspective

Dropdown menu