Fixed rendering

+ Cloning support in Board and Piece
- Using clones for board operations that interfere with rendering
- Fixed repaint calls
+ Unit test for testing board cloning

.classpath

@@ -7,5 +7,6 @@
 		</attributes>
 	</classpathentry>
 	<classpathentry kind="lib" path="res"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/5"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

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

@@ -14,7 +14,7 @@ import dev.kske.chess.board.Piece.Type;
  * Created: <strong>01.07.2019</strong><br>
  * Author: <strong>Kai S. K. Engelbart</strong>
  */
-public class Board {
+public class Board implements Cloneable {
 
 	private Piece[][]				boardArr;
 	private Map<Color, Position>	kingPos;
@@ -35,10 +35,7 @@ public class Board {
 		Piece piece = getPos(move);
 		if (piece == null || !piece.isValidMove(move)) return false;
 		else {
-			/*
-			 * Move piece
-			 * Save destination piece for possible canceling of the move
-			 */
+			// Move piece
 			Piece capturePiece = move(move);
 
 			// Revert move if it caused a check for its team
@@ -223,6 +220,32 @@ public class Board {
 				boardArr[i][j] = null;
 	}
 
+	/**
+	 * @return A new instance of this class with a shallow copy of both
+	 *         {@code kingPos} and {code boardArr}
+	 */
+	@Override
+	public Object clone() {
+		Board board = null;
+		try {
+			board = (Board) super.clone();
+		} catch (CloneNotSupportedException ex) {
+			ex.printStackTrace();
+		}
+		board.boardArr = new Piece[8][8];
+		for (int i = 0; i < 8; i++)
+			for (int j = 0; j < 8; j++) {
+				if (boardArr[i][j] == null) continue;
+				board.boardArr[i][j]		= (Piece) boardArr[i][j].clone();
+				board.boardArr[i][j].board	= board;
+			}
+
+		board.kingPos	= new HashMap<>();
+		board.kingPos.putAll(kingPos);
+
+		return board;
+	}
+
 	public Piece get(Position pos) {
 		return boardArr[pos.x][pos.y];
 	}

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

@@ -9,7 +9,7 @@ import java.util.List;
  * Created: <strong>01.07.2019</strong><br>
  * Author: <strong>Kai S. K. Engelbart</strong>
  */
-public abstract class Piece {
+public abstract class Piece implements Cloneable {
 
 	protected Color	color;
 	protected Board	board;
@@ -51,6 +51,17 @@ public abstract class Piece {
 		return board.getDest(move) == null || board.getDest(move).getColor() != getColor();
 	}
 
+	@Override
+	public Object clone() {
+		Piece piece = null;
+		try {
+			piece = (Piece) super.clone();
+		} catch (CloneNotSupportedException ex) {
+			ex.printStackTrace();
+		}
+		return piece;
+	}
+
 	public abstract Type getType();
 
 	public Color getColor() { return color; }

src/dev/kske/chess/game/AIPlayer.java

@@ -1,5 +1,7 @@
 package dev.kske.chess.game;
 
+import javax.swing.SwingUtilities;
+
 import dev.kske.chess.board.Board;
 import dev.kske.chess.board.Move;
 import dev.kske.chess.board.Piece;
@@ -22,10 +24,12 @@ public class AIPlayer extends Player {
 
 	@Override
 	public void requestMove() {
+		new Thread(() -> {
 			count = 0;
-		findBestMove(board, color, 0);
+			findBestMove((Board) board.clone(), color, 0);
 			System.out.println("Moved processes: " + count);
-		game.onMove(this, bestMove);
+			SwingUtilities.invokeLater(() -> game.onMove(this, bestMove));
+		}).start();
 	}
 
 	private int findBestMove(Board board, Color color, int depth) {

src/dev/kske/chess/game/Game.java

@@ -36,8 +36,6 @@ public class Game {
 	public void onMove(Player player, Move move) {
 		if (board.getPos(move).getColor() == player.color && board.attemptMove(move)) {
 			System.out.printf("%s: %s%n", player.color, move);
-			boardPanel.repaint();
-
 			GameState eventType = board.getGameEventType(board.getDest(move).getColor().opposite());
 			switch (eventType) {
 				case CHECKMATE:
@@ -47,7 +45,9 @@ public class Game {
 				case CHECK:
 					System.out.printf("%s in check!%n", player.color);
 				default:
+					boardPanel.repaint();
 					players.get(player.color.opposite()).requestMove();
+
 			}
 		} else {
 			System.out.printf("%s: Illegal move!%n", player.getColor());

src/dev/kske/chess/game/NaturalPlayer.java

@@ -33,6 +33,7 @@ public class NaturalPlayer extends Player {
 					pos = new Position(evt.getPoint().x / boardPanel.getTileSize(),
 							evt.getPoint().y / boardPanel.getTileSize());
 
+					Board board = (Board) NaturalPlayer.this.board.clone();
 					if (board.get(pos) != null && board.get(pos).getColor() == color)
 						boardPanel.displayMoves(board.getMoves(pos));
 					else pos = null;

src/dev/kske/chess/test/BoardCloneTest.java

@@ -0,0 +1,44 @@
+package dev.kske.chess.test;
+
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotSame;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import dev.kske.chess.board.Board;
+import dev.kske.chess.board.Piece.Color;
+import dev.kske.chess.board.Queen;
+
+/**
+ * Project: <strong>Chess</strong><br>
+ * File: <strong>BoardCloneTest.java</strong><br>
+ * Created: <strong>08.07.2019</strong><br>
+ * Author: <strong>Kai S. K. Engelbart</strong>
+ */
+class BoardCloneTest {
+
+	Board board;
+
+	/**
+	 * @throws java.lang.Exception
+	 */
+	@BeforeEach
+	void setUp() throws Exception {
+		board = new Board();
+	}
+
+	/**
+	 * Test method for {@link dev.kske.chess.board.Board#clone()}.
+	 */
+	@Test
+	void testClone() {
+		Board clone = (Board) board.clone();
+		assertNotSame(clone, board);
+		assertNotSame(clone.getBoardArr(), board.getBoardArr());
+
+		clone.getBoardArr()[0][0] = new Queen(Color.BLACK, clone);
+		assertNotEquals(clone.getBoardArr()[0][0], board.getBoardArr()[0][0]);
+	}
+
+}