OOD / Game• Patterns: Factory Method, Command

Chess

Hard

Problem Summary

Design a chess engine supporting pieces behavior, move validations, board states, checkmate rules, and move rollbacks.

Functional Scope

White and Black players execute turn-based moves.
Pieces (King, Queen, Pawn) validate their legal trajectories.
Checkmate/stalemate validation algorithms.
Support transaction history/undo moves.

Entity-Relationship (ER) Schema

Game [1] <---> [1] Board
Game [1] <---> [2] Player
Board [1] <---> [64] Cell
Cell [1] <---> [0..1] Piece
Game [1] <---> [*] Move

Design Approach

Model Chess pieces by subclassing a base Piece class with custom canMove rules. Use the Command pattern for Move objects to support action validation, turn logs, and undo actions.

Core Classes & Models

Board (8x8 grid of Cells)Cell (Tracks Row, Column, and current Piece)Piece (Base class defining getLegalMoves)Move (Tracks start and end Cells, capturing history)Game (Manages turn history, game status)

Code Blueprint

public abstract class Piece {
    public abstract boolean canMove(Board b, Cell start, Cell end);
}