Monday 2 July 2018

Design Chess game

Chess Game Design

Here give an example about an object oriented design of a chess game.

The design can be modularized into four parts: board, piece sets, game and player.


A Board class has an attribute of Squares Array (8x8) and PieceSets (black and white).

A Board class also has an attribute of "pieceSetOnTop". The attribute helps to figure the piece moves that are direction-restricted.


A PieceSet class has an attribute of a List<Piece>. The size of the List<Piece> is initially set to 16.

A Piece class has two attributes: color and placeAt (i.e. located at which square).

A Piece class is an abstract class. The extended classes (Pawn, King, Queen, Rook, Knight, Bishop) implements the abstracted operations:

  • validMoves() - The valid movement for a Piece
  • attackSquares() - The squares that a Piece can attack
  • captureFreeMove - The squares that a Piece can move to without being captured. 
  • toBeCaptured() - The boolean indicates whether a Piece is going to be captured.

The validMoves() operation implements the movement rules. For example, the validMoves of a Pawn class ensures that the Pawn can only move in the direction towards the opponent side. A Pawn class has additional attributes of promoted and promotedTo, which describes the movement/conversion rule of a Pawn at reaching the end of an opponent side and at the conversion about the piece that a Pawn converted to.


A Game class controls the flow of a game. The class has attributes:

  • playedMoves - Keep a record of moves
  • turn - Indicate either it is a Black's turn or a White's turn
  • players - Represent the two players, this can be Human/Human, Computer/Computer or Human/Computer
  • result - Indicate the result of a game
  • checkStatus - Indicate which side is being checked or checkmated


A Player class represents a Player. A Player has two attributes:

  • pieceColor - The color that used by a Player
  • engine - The engine that makes the moves. This can be a human or a computer

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