1 public class ChessPieceTurn { };2 public class GameManager {3 void processTurn(PlayerBase player) { };4 boolean acceptTurn(ChessPieceTurn turn) { return true; };5 Position currentPosition;6 }78 public abstract class PlayerBase {9 public abstract ChessPieceTurn getTurn(Position p);10 }11 class ComputerPlayer extends PlayerBase {12 public ChessPieceTurn getTurn(Position p) { return null; }13 public void setDifficulty() { };14 public PositionEstimator estimater;15 public PositionBackTracker backtracter;16 }17 public class HumanPlayer extends PlayerBase {18 public ChessPieceTurn getTurn(Position p) { return null; }19 }2021 public abstract class ChessPieceBase {22 abstract boolean canBeChecked();23 abstract boolean isSupportCastle();24 }25 public class King extends ChessPieceBase { ... }26 public class Queen extends ChessPieceBase { ... }2728 public class Position { // represents chess positions in compact form29 ArrayList<ChessPieceBase> black;30 ArrayList<ChessPieceBase> white;31 }3233 public class PositionBackTracker {34 public static Position getNext(Position p) { return null; }35 }36 public class PositionEstimator {37 public static PositionPotentialValue estimate(Position p) { ... }38 }39 public abstract class PositionPotentialValue {40 abstract boolean lessThan(PositionPotentialValue pv);41 }