Added a PGN file saving routine

+ showFileSaveDialog in DialogUtil
+ Javadoc in Log and PGNDatabase
+ "Save game file" button in MenuBar
+ saveFile method in MainWindow
+ Formatting and result tag in PGNGame tag pair serialization

src/dev/kske/chess/board/Log.java

@@ -49,6 +49,11 @@ public class Log implements Iterable<MoveNode> {
 		}
 	}
 
+	/**
+	 * @return an iterator over all {@link MoveNode} objects that are either the
+	 *         root node or a first variation of another node, starting from the
+	 *         root node
+	 */
 	@Override
 	public Iterator<MoveNode> iterator() {
 		return new Iterator<MoveNode>() {
@@ -98,7 +103,7 @@ public class Log implements Iterable<MoveNode> {
 	}
 
 	/**
-	 * Removed the last move from the log and adjusts its state to the previous
+	 * Removes the last move from the log and adjusts its state to the previous
 	 * move.
 	 */
 	public void removeLast() {
@@ -165,6 +170,10 @@ public class Log implements Iterable<MoveNode> {
 		}
 	}
 
+	/**
+	 * Sets the active color, castling rights, en passant target square, fullmove
+	 * number and halfmove clock to those of the current {@link MoveNode}.
+	 */
 	private void update() {
 		activeColor		= current.activeColor;
 		castlingRights	= current.castlingRights.clone();
@@ -173,6 +182,15 @@ public class Log implements Iterable<MoveNode> {
 		halfmoveClock	= current.halfmoveClock;
 	}
 
+	/**
+	 * Removed the castling rights bound to a rook or king for the rest of the game.
+	 * This method should be called once the piece has been moved, as a castling
+	 * move involving this piece is forbidden afterwards.
+	 * 
+	 * @param piece           the rook or king to disable the castling rights for
+	 * @param initialPosition the initial position of the piece during the start of
+	 *                        the game
+	 */
 	private void disableCastlingRights(Piece piece, Position initialPosition) {
 		// Kingside
 		if (piece instanceof King || piece instanceof Rook && initialPosition.x == 7)

src/dev/kske/chess/pgn/PGNDatabase.java

@@ -2,6 +2,7 @@ package dev.kske.chess.pgn;
 
 import java.io.File;
 import java.io.FileNotFoundException;
+import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.List;
@@ -13,6 +14,9 @@ import dev.kske.chess.exception.ChessException;
  * Project: <strong>Chess</strong><br>
  * File: <strong>PGNDatabase.java</strong><br>
  * Created: <strong>4 Oct 2019</strong><br>
+ * <br>
+ * Contains a series of {@link PGNGame} objects that can be stored inside a PGN
+ * file.
  * 
  * @since Chess v0.5-alpha
  * @author Kai S. K. Engelbart
@@ -21,6 +25,13 @@ public class PGNDatabase {
 
 	private final List<PGNGame> games = new ArrayList<>();
 
+	/**
+	 * Loads PGN games from a file.
+	 * 
+	 * @param pgnFile the file to load the games from
+	 * @throws FileNotFoundException if the specified file is not found
+	 * @throws ChessException        if an error occurs while parsing the file
+	 */
 	public void load(File pgnFile) throws FileNotFoundException, ChessException {
 		Scanner sc = new Scanner(pgnFile);
 		while (sc.hasNext())
@@ -28,7 +39,14 @@ public class PGNDatabase {
 		sc.close();
 	}
 
-	public void save(File pgnFile) throws FileNotFoundException {
+	/**
+	 * Saves PGN games to a file.
+	 * 
+	 * @param pgnFile the file to save the games to.
+	 * @throws IOException if the file could not be created
+	 */
+	public void save(File pgnFile) throws IOException {
+		pgnFile.getParentFile().mkdirs();
 		PrintWriter pw = new PrintWriter(pgnFile);
 		games.forEach(g -> g.writePGN(pw));
 		pw.close();

src/dev/kske/chess/pgn/PGNGame.java

@@ -23,7 +23,11 @@ import dev.kske.chess.exception.ChessException;
 public class PGNGame {
 
 	private final Map<String, String>	tagPairs	= new HashMap<>(7);
-	private final Board					board		= new Board();
+	private final Board					board;
+
+	public PGNGame() { board = new Board(); }
+
+	public PGNGame(Board board) { this.board = board; }
 
 	public static PGNGame parse(Scanner sc) throws ChessException {
 		PGNGame game = new PGNGame();
@@ -65,17 +69,23 @@ public class PGNGame {
 	}
 
 	public void writePGN(PrintWriter pw) {
+		// Set the unknown result tag if no result tag is specified
+		tagPairs.putIfAbsent("Result", "*");
+
 		// Write tag pairs
 		tagPairs.forEach((k, v) -> pw.printf("[%s \"%s\"]%n", k, v));
 
+		// Insert newline if tags were printed
+		if (!tagPairs.isEmpty()) pw.println();
+
 		// Write movetext
 		board.getLog().forEach(m -> {
 			if (m.activeColor == Color.BLACK) pw.printf("%d. ", m.fullmoveCounter);
-			pw.print(m.move); // TODO: Convert to SAN
+			pw.printf("%s ", m.move); // TODO: Convert to SAN
 		});
 
-		// TODO: Write game termination marker
-		// TODO: Check if the game has ended
+		// Write game termination marker
+		pw.print(tagPairs.get("Result"));
 	}
 
 	public String getTag(String tagName) { return tagPairs.get(tagName); }

src/dev/kske/chess/ui/DialogUtil.java

@@ -5,6 +5,7 @@ import java.awt.Font;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
@@ -15,7 +16,7 @@ import javax.swing.JFileChooser;
 import javax.swing.JLabel;
 import javax.swing.JOptionPane;
 import javax.swing.JPanel;
-import javax.swing.filechooser.FileFilter;
+import javax.swing.filechooser.FileNameExtensionFilter;
 
 import dev.kske.chess.io.EngineUtil;
 
@@ -31,27 +32,24 @@ public class DialogUtil {
 
 	private DialogUtil() {}
 
-	public static void showFileSelectionDialog(Component parent, Consumer<List<File>> action) {
+	public static void showFileSelectionDialog(Component parent, Consumer<List<File>> action, Collection<FileNameExtensionFilter> filters) {
 		JFileChooser fileChooser = new JFileChooser();
 		fileChooser.setCurrentDirectory(new File(System.getProperty("user.home")));
 		fileChooser.setAcceptAllFileFilterUsed(false);
-		fileChooser.addChoosableFileFilter(new FileFilter() {
-
-			@Override
-			public boolean accept(File f) {
-				int dotIndex = f.getName().lastIndexOf('.');
-				if (dotIndex >= 0) {
-					String extension = f.getName().substring(dotIndex).toLowerCase();
-					return extension.equals(".fen") || extension.equals(".pgn");
-				} else return f.isDirectory();
-			}
-
-			@Override
-			public String getDescription() { return "FEN and PGN files"; }
-		});
+		filters.forEach(fileChooser::addChoosableFileFilter);
 		if (fileChooser.showOpenDialog(parent) == JFileChooser.APPROVE_OPTION) action.accept(Arrays.asList(fileChooser.getSelectedFile()));
 	}
 
+	public static void showFileSaveDialog(Component parent, Consumer<File> action, Collection<FileNameExtensionFilter> filters) {
+		JFileChooser fileChooser = new JFileChooser();
+		fileChooser.setCurrentDirectory(new File(System.getProperty("user.home")));
+		fileChooser.setAcceptAllFileFilterUsed(false);
+		filters.forEach(fileChooser::addChoosableFileFilter);
+		if (fileChooser.showSaveDialog(parent) == JFileChooser.APPROVE_OPTION) action.accept(
+				new File(fileChooser.getSelectedFile().getAbsolutePath() + "."
+						+ ((FileNameExtensionFilter) fileChooser.getFileFilter()).getExtensions()[0]));
+	}
+
 	public static void showGameConfigurationDialog(Component parent, BiConsumer<String, String> action) {
 		JPanel dialogPanel = new JPanel();
 

src/dev/kske/chess/ui/MainWindow.java

@@ -4,6 +4,7 @@ import java.awt.EventQueue;
 import java.awt.Toolkit;
 import java.awt.dnd.DropTarget;
 import java.io.File;
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
@@ -164,4 +165,25 @@ public class MainWindow extends JFrame {
 			}
 		});
 	}
+
+	public void saveFile(File file) {
+		final int		dotIndex	= file.getName().lastIndexOf('.');
+		final String	name		= file.getName().substring(0, dotIndex);
+		final String	extension	= file.getName().substring(dotIndex).toLowerCase();
+
+		if (extension.equals(".pgn")) try {
+			PGNGame pgnGame = new PGNGame(getSelectedGamePane().getGame().getBoard());
+			pgnGame.setTag("Event", tabbedPane.getTitleAt(tabbedPane.getSelectedIndex()));
+			pgnGame.setTag("Result", "*");
+			PGNDatabase pgnDB = new PGNDatabase();
+			pgnDB.getGames().add(pgnGame);
+			pgnDB.save(file);
+		} catch (IOException e) {
+			e.printStackTrace();
+			JOptionPane.showMessageDialog(this,
+					"Failed to save the file " + file.getName() + ": " + e.toString(),
+					"File saving error",
+					JOptionPane.ERROR_MESSAGE);
+		}
+	}
 }

src/dev/kske/chess/ui/MenuBar.java

@@ -2,11 +2,13 @@ package dev.kske.chess.ui;
 
 import java.awt.Toolkit;
 import java.awt.datatransfer.StringSelection;
+import java.util.Arrays;
 
 import javax.swing.JMenu;
 import javax.swing.JMenuBar;
 import javax.swing.JMenuItem;
 import javax.swing.JOptionPane;
+import javax.swing.filechooser.FileNameExtensionFilter;
 
 import dev.kske.chess.board.FENString;
 import dev.kske.chess.exception.ChessException;
@@ -48,9 +50,18 @@ public class MenuBar extends JMenuBar {
 		gameMenu.add(newGameMenuItem);
 
 		JMenuItem loadFileMenu = new JMenuItem("Load game file");
-		loadFileMenu.addActionListener((evt) -> DialogUtil.showFileSelectionDialog(mainWindow, mainWindow::loadFiles));
+		loadFileMenu.addActionListener((evt) -> DialogUtil
+			.showFileSelectionDialog(mainWindow,
+					mainWindow::loadFiles,
+					Arrays.asList(new FileNameExtensionFilter("FEN and PGN files", "fen", "pgn"))));
 		gameMenu.add(loadFileMenu);
 
+		JMenuItem saveFileMenu = new JMenuItem("Save game file");
+		saveFileMenu
+			.addActionListener((evt) -> DialogUtil
+				.showFileSaveDialog(mainWindow, mainWindow::saveFile, Arrays.asList(new FileNameExtensionFilter("PGN file", "pgn"))));
+		gameMenu.add(saveFileMenu);
+
 		add(gameMenu);
 		newGameMenuItem.doClick();
 	}