State Design Pattern

IBoardModel

execute(IBoardStatusVisitor v, …)

state.execute(v, …)

TicTacToeBoard

ABoardState

v.noWinnerCase(…)

ATerminalState

NonTerminalState

Player0Won

Player1Won

DrawGame

v.player0WonCase(…)

v.player1WonCase(…)

v.drawCase(…)