Chess Application Class Design Using the Abstract Factory Design Pattern

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Introduction

The following article is a base class that can be used to develop a chess board application. The design of the application is based on the Abstract Factory Design Pattern.

Background

I wrote this article as an update to my previous article called "Easy to use ASP.NET Chessboard control". Many people complained that I did not use an Object Oriented approach - so, I've built this basic component framework now for anyone wanting to develop a chess board application.

Using the Code

The code makes use of the Abstract Factory pattern - I've built a main ChessFactory class and then two other classes called WhiteChessFactory and BlackChessFactory that inherit from the ChessFactory class. To display the concepts, I've built a very basic Windows app that asks the user if he wants the white or black pieces. (Please note that the actual chess board application has still not been added - this is just the basic class structure of the application.)

Public MustInherit Class ChessFactory
    Public MustOverride Function CreateKing() As King
    Public MustOverride Function CreateQueen() As Queen
    Public MustOverride Function CreateRook() As Rook
    Public MustOverride Function CreateBishop() As Bishop
    Public MustOverride Function CreateKnight() As Knight
    Public MustOverride Function CreatePawn() As Pawn
End Class

Public Class WhiteChessFactory : Inherits ChessFactory

    Public Overrides Function CreateKing() As King
        Return New WhiteKing()
    End Function

    Public Overrides Function CreateQueen() As Queen
        Return New WhiteQueen()
    End Function

    Public Overrides Function CreateRook() As Rook
        Return New WhiteRook()
    End Function

    Public Overrides Function CreateBishop() As Bishop
        Return New WhiteBishop()
    End Function

    Public Overrides Function CreateKnight() As Knight
        Return New WhiteKnight()
    End Function

    Public Overrides Function CreatePawn() As Pawn
        Return New WhitePawn()
    End Function

End Class

For each of the chess pieces, a separate class has then be created.

Points of Interest

The chess class design has provided an interface for creating families or related or dependent objects without specifying their concrete classes.

History

If anyone is interested in adding some additional functionality to the classes to build the actual chess application, then email me at louwgi@avusa.co.za.