basic model

app/src/main/java/chess/model/PieceVisitor.java

@@ -0,0 +1,28 @@
+package chess.model;
+
+import chess.model.pieces.Bishop;
+import chess.model.pieces.King;
+import chess.model.pieces.Knight;
+import chess.model.pieces.Pawn;
+import chess.model.pieces.Queen;
+import chess.model.pieces.Rook;
+
+public interface PieceVisitor<T> {
+
+	default T visit(Piece piece) {
+		return piece.accept(this);
+	}
+
+	T visitPiece(Bishop bishop);
+
+	T visitPiece(King king);
+
+	T visitPiece(Knight knight);
+
+	T visitPiece(Pawn pawn);
+
+	T visitPiece(Queen queen);
+
+	T visitPiece(Rook rook);
+
+}