add getPiecesWithColor() function - Board class

src/board/Board.java

@@ -1,9 +1,11 @@
 package board;
 
+import general.Color;
 import general.Square;
 import general.Player;
 import pieces.Piece;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 
 abstract public class Board {
@@ -56,6 +58,18 @@ public Piece getPieceAt(Square square) {
         return pieces[square.getRow()][square.getColumn()];
     }
 
+    public ArrayList<Piece> getPiecesWithColor(Player player) {
+        ArrayList<Piece> result = new ArrayList<>();
+        for (int i = 0; i < 8; i++) {
+            for (int j = 0; j < 8; j++) {
+                if (pieces[i][j] != null && player.equals(pieces[i][j].getOwner())) {
+                    result.add(pieces[i][j]);
+                }
+            }
+        }
+        return result;
+    }
+
     public abstract void initializeBoardWithPieces(Player white, Player black);
 
     @Override

src/general/GameStatesChecker.java

@@ -0,0 +1,23 @@
+package general;
+
+import board.StandardChessBoard;
+import pieces.Piece;
+
+public class GameState {
+    public boolean isStillInCheck(StandardChessBoard board, Square from, Square to) {
+        board.removePiece(board.getPieceAt(to));
+        Piece currentPiece = board.getPieceAt(from);
+        board.removePiece(currentPiece);
+        currentPiece.setLocation(to);
+        board.addPiece(currentPiece);
+        return isCheck(board);
+    }
+
+    public boolean isCheck(StandardChessBoard board) {
+        return true;
+    }
+
+    public boolean isCheckMate() {
+        return true;
+    }
+}