Added block checking to move validation

+ Move class
+ Utility methods in Board
+ isFreePath method in Piece with implementations in every subclass

- Pawn movement is still not fully implemented, including promotion, en
passant and movement over two tiles

src/dev/kske/chess/Board.java

@@ -25,49 +25,71 @@ public class Board {
 	}
 
 	public boolean move(int xPos, int yPos, int xDest, int yDest) {
-		if (boardArr[xPos][yPos] == null || !boardArr[xPos][yPos].isValidMove(xPos, yPos, xDest, yDest)) return false;
+		return move(new Move(xPos, yPos, xDest, yDest));
+	}
+
+	public boolean move(Move move) {
+		Piece piece = getPos(move);
+		if (piece == null || !piece.isValidMove(move)) return false;
 		else {
-			boardArr[xDest][yDest]	= boardArr[xPos][yPos];
-			boardArr[xPos][yPos]	= null;
+			// Move piece
+			setDest(move, getPos(move));
+			setPos(move, null);
 			return true;
 		}
 	}
 
+	public Piece getPos(Move move) {
+		return boardArr[move.xPos][move.yPos];
+	}
+
+	public Piece getDest(Move move) {
+		return boardArr[move.xDest][move.yDest];
+	}
+
+	public void setPos(Move move, Piece piece) {
+		boardArr[move.xPos][move.yPos] = piece;
+	}
+
+	public void setDest(Move move, Piece piece) {
+		boardArr[move.xDest][move.yDest] = piece;
+	}
+
 	/**
 	 * Initialized the board array with the default chess pieces and positions.
 	 */
 	private void initializeDefaultPositions() {
 		// Initialize pawns
 		for (int i = 0; i < 8; i++) {
-			boardArr[i][1]	= new Pawn(Color.BLACK);
-			boardArr[i][6]	= new Pawn(Color.WHITE);
+			boardArr[i][1]	= new Pawn(Color.BLACK, this);
+			boardArr[i][6]	= new Pawn(Color.WHITE, this);
 		}
 
 		// Initialize kings
-		boardArr[4][0]	= new King(Color.BLACK);
-		boardArr[4][7]	= new King(Color.WHITE);
+		boardArr[4][0]	= new King(Color.BLACK, this);
+		boardArr[4][7]	= new King(Color.WHITE, this);
 
 		// Initialize queens
-		boardArr[3][0]	= new Queen(Color.BLACK);
-		boardArr[3][7]	= new Queen(Color.WHITE);
+		boardArr[3][0]	= new Queen(Color.BLACK, this);
+		boardArr[3][7]	= new Queen(Color.WHITE, this);
 
 		// Initialize rooks
-		boardArr[0][0]	= new Rook(Color.BLACK);
-		boardArr[0][7]	= new Rook(Color.WHITE);
-		boardArr[7][0]	= new Rook(Color.BLACK);
-		boardArr[7][7]	= new Rook(Color.WHITE);
+		boardArr[0][0]	= new Rook(Color.BLACK, this);
+		boardArr[0][7]	= new Rook(Color.WHITE, this);
+		boardArr[7][0]	= new Rook(Color.BLACK, this);
+		boardArr[7][7]	= new Rook(Color.WHITE, this);
 
 		// Initialize knights
-		boardArr[1][0]	= new Knight(Color.BLACK);
-		boardArr[1][7]	= new Knight(Color.WHITE);
-		boardArr[6][0]	= new Knight(Color.BLACK);
-		boardArr[6][7]	= new Knight(Color.WHITE);
+		boardArr[1][0]	= new Knight(Color.BLACK, this);
+		boardArr[1][7]	= new Knight(Color.WHITE, this);
+		boardArr[6][0]	= new Knight(Color.BLACK, this);
+		boardArr[6][7]	= new Knight(Color.WHITE, this);
 
 		// Initialize bishops
-		boardArr[2][0]	= new Bishop(Color.BLACK);
-		boardArr[2][7]	= new Bishop(Color.WHITE);
-		boardArr[5][0]	= new Bishop(Color.BLACK);
-		boardArr[5][7]	= new Bishop(Color.WHITE);
+		boardArr[2][0]	= new Bishop(Color.BLACK, this);
+		boardArr[2][7]	= new Bishop(Color.WHITE, this);
+		boardArr[5][0]	= new Bishop(Color.BLACK, this);
+		boardArr[5][7]	= new Bishop(Color.WHITE, this);
 	}
 
 	/**

src/dev/kske/chess/Move.java

@@ -0,0 +1,29 @@
+package dev.kske.chess;
+
+/**
+ * Project: <strong>Chess</strong><br>
+ * File: <strong>Move.java</strong><br>
+ * Created: <strong>02.07.2019</strong><br>
+ * Author: <strong>Kai S. K. Engelbart</strong>
+ */
+public class Move {
+
+	public final int xPos, yPos, xDest, yDest, xDist, yDist, xSign, ySign;
+
+	public Move(int xPos, int yPos, int xDest, int yDest) {
+		this.xPos	= xPos;
+		this.yPos	= yPos;
+		this.xDest	= xDest;
+		this.yDest	= yDest;
+		xDist		= Math.abs(xDest - xPos);
+		yDist		= Math.abs(yDest - yPos);
+		xSign		= (int) Math.signum(xDest - xPos);
+		ySign		= (int) Math.signum(yDest - yPos);
+	}
+
+	public boolean isHorizontal() { return yDist == 0; }
+
+	public boolean isVertical() { return xDist == 0; }
+
+	public boolean isDiagonal() { return xDist == yDist; }
+}

src/dev/kske/chess/piece/Bishop.java

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>Bishop.java</strong><br>
@@ -8,13 +11,21 @@ package dev.kske.chess.piece;
  */
 public class Bishop extends Piece {
 
-	public Bishop(Color color) {
-		super(color);
+	public Bishop(Color color, Board board) {
+		super(color, board);
 	}
 
 	@Override
-	public boolean isValidMove(int xPos, int yPos, int xDest, int yDest) {
-		return Math.abs(xDest - xPos) == Math.abs(yDest - yPos);
+	public boolean isValidMove(Move move) {
+		return move.isDiagonal() && isFreePath(move);
+	}
+
+	@Override
+	protected boolean isFreePath(Move move) {
+		for (int i = move.xPos + move.xSign, j = move.yPos
+				+ move.ySign; i != move.xDest; i += move.xSign, j += move.ySign)
+			if (board.getBoardArr()[i][j] != null) return false;
+		return checkDestination(move);
 	}
 
 	@Override

src/dev/kske/chess/piece/King.java

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>King.java</strong><br>
@@ -8,13 +11,13 @@ package dev.kske.chess.piece;
  */
 public class King extends Piece {
 
-	public King(Color color) {
-		super(color);
+	public King(Color color, Board board) {
+		super(color, board);
 	}
 
 	@Override
-	public boolean isValidMove(int xPos, int yPos, int xDest, int yDest) {
-		return Math.abs(xDest - xPos) <= 1 && Math.abs(yDest - yPos) <= 1;
+	public boolean isValidMove(Move move) {
+		return move.xDist <= 1 && move.yDist <= 1 && isFreePath(move);
 	}
 
 	@Override

src/dev/kske/chess/piece/Knight.java

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>Knight.java</strong><br>
@@ -8,15 +11,13 @@ package dev.kske.chess.piece;
  */
 public class Knight extends Piece {
 
-	public Knight(Color color) {
-		super(color);
+	public Knight(Color color, Board board) {
+		super(color, board);
 	}
 
 	@Override
-	public boolean isValidMove(int xPos, int yPos, int xDest, int yDest) {
-		int	xDist	= Math.abs(xDest - xPos);
-		int	yDist	= Math.abs(yDest - yPos);
-		return Math.abs(xDist - yDist) == 1 && xDist != 0 && yDist != 0;
+	public boolean isValidMove(Move move) {
+		return Math.abs(move.xDist - move.yDist) == 1 && move.xDist != 0 && move.yDist != 0 && isFreePath(move);
 	}
 
 	@Override

src/dev/kske/chess/piece/Pawn.java

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>Pawn.java</strong><br>
@@ -8,16 +11,31 @@ package dev.kske.chess.piece;
  */
 public class Pawn extends Piece {
 
-	public Pawn(Color color) {
-		super(color);
+	public Pawn(Color color, Board board) {
+		super(color, board);
 	}
 
 	@Override
-	public boolean isValidMove(int xPos, int yPos, int xDest, int yDest) {
-		int	direction	= color == Color.WHITE ? -1 : 1;
-		int	xDist		= Math.abs(xDest - xPos);
-		int	yDist		= (yDest - yPos) * direction;
-		return (xDist == 0 && yDist > 0 && yDist <= 2) || (xDist == 1 && yDist == 1);
+	public boolean isValidMove(Move move) {
+		// TODO: Positioning, en passant
+		if (getColor() == Color.WHITE)
+			return ((move.xDist == 0 && move.yDist > 0 && move.yDist <= 2) || (move.xDist == 1 && move.yDist == 1))
+					&& move.ySign == -1 && isFreePath(move);
+		else return ((move.xDist == 0 && move.yDist > 0 && move.yDist <= 2) || (move.xDist == 1 && move.yDist == 1))
+				&& move.ySign == 1
+				&& isFreePath(move);
+
+	}
+
+	@Override
+	protected boolean isFreePath(Move move) {
+		// Two steps forward
+		if (move.yDist == 2)
+			return board.getBoardArr()[move.xPos][move.yDest - move.ySign] == null && checkDestination(move);
+		// One step forward
+		else if (move.xDist == 0) return board.getDest(move) == null;
+		// Capture move
+		else return board.getDest(move) != null && board.getDest(move).getColor() != getColor();
 	}
 
 	@Override

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

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>Piece.java</strong><br>
@@ -9,12 +12,30 @@ package dev.kske.chess.piece;
 public abstract class Piece {
 
 	protected Color	color;
+	protected Board	board;
 
-	public Piece(Color color) {
+	public Piece(Color color, Board board) {
 		this.color	= color;
+		this.board	= board;
 	}
 
-	public abstract boolean isValidMove(int xPos, int yPos, int xDest, int yDest);
+	public abstract boolean isValidMove(Move move);
+
+	protected boolean isFreePath(Move move) {
+		// Only check destination by default
+		return checkDestination(move);
+	}
+
+	/**
+	 * Checks if the destination of a move is empty or a piece from the opposing
+	 * team
+	 * 
+	 * @param move The move to check
+	 * @return {@code false} if the move's destination is from the same team
+	 */
+	protected final boolean checkDestination(Move move) {
+		return board.getDest(move) == null || board.getDest(move).getColor() != getColor();
+	}
 
 	public abstract Type getType();
 

src/dev/kske/chess/piece/Queen.java

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>Queen.java</strong><br>
@@ -8,13 +11,29 @@ package dev.kske.chess.piece;
  */
 public class Queen extends Piece {
 
-	public Queen(Color color) {
-		super(color);
+	public Queen(Color color, Board board) {
+		super(color, board);
 	}
 
 	@Override
-	public boolean isValidMove(int xPos, int yPos, int xDest, int yDest) {
-		return (xPos == xDest || yPos == yDest) || (Math.abs(xDest - xPos) == Math.abs(yDest - yPos));
+	public boolean isValidMove(Move move) {
+		return ((move.isHorizontal() || move.isVertical()) || move.isDiagonal()) && isFreePath(move);
+	}
+
+	@Override
+	protected boolean isFreePath(Move move) {
+		if (move.isHorizontal()) {
+			for (int i = move.xPos + move.xSign; i != move.xDest; i += move.xSign)
+				if (board.getBoardArr()[i][move.yPos] != null) return false;
+		} else if (move.isVertical()) {
+			for (int i = move.yPos + move.ySign; i != move.yDest; i += move.ySign)
+				if (board.getBoardArr()[move.xPos][i] != null) return false;
+		} else {
+			for (int i = move.xPos + move.xSign, j = move.yPos
+					+ move.ySign; i != move.xDest; i += move.xSign, j += move.ySign)
+				if (board.getBoardArr()[i][j] != null) return false;
+		}
+		return checkDestination(move);
 	}
 
 	@Override

src/dev/kske/chess/piece/Rook.java

@@ -1,5 +1,8 @@
 package dev.kske.chess.piece;
 
+import dev.kske.chess.Board;
+import dev.kske.chess.Move;
+
 /**
  * Project: <strong>Chess</strong><br>
  * File: <strong>Rook.java</strong><br>
@@ -8,13 +11,25 @@ package dev.kske.chess.piece;
  */
 public class Rook extends Piece {
 
-	public Rook(Color color) {
-		super(color);
+	public Rook(Color color, Board board) {
+		super(color, board);
 	}
 
 	@Override
-	public boolean isValidMove(int xPos, int yPos, int xDest, int yDest) {
-		return xPos == xDest || yPos == yDest;
+	public boolean isValidMove(Move move) {
+		return (move.isHorizontal() || move.isVertical()) && isFreePath(move);
+	}
+
+	@Override
+	protected boolean isFreePath(Move move) {
+		if (move.isHorizontal()) {
+			for (int i = move.xPos + move.xSign; i != move.xDest; i += move.xSign)
+				if (board.getBoardArr()[i][move.yPos] != null) return false;
+		} else {
+			for (int i = move.yPos + move.ySign; i != move.yDest; i += move.ySign)
+				if (board.getBoardArr()[move.xPos][i] != null) return false;
+		}
+		return checkDestination(move);
 	}
 
 	@Override