Ćwiczenie z refaktoryzacjiĆwiczenie z refaktoryzacji(na podstawie Refactoring Workbook)(na podstawie Refactoring Workbook)

Szkolenie dla NaviExpert, 22.02.2011

AgendaAgenda

Refactoring exercises simple game example (by W. Wake) dining philosphers

A simple gameA simple game

Rules the game implements a simplistic example of a tic-tac-toe

family there is a board divided into squares, which are occupied by

different markers; every player has different marker ('X' or 'O') it this case the board is linear and is 9 squares long given a set and a player marker, the program answers with a

move the winner is the party that lines up a sequence of three

markers in a row the program is to be extended in future

A simple gameA simple gamepublic class Game { public StringBuffer board;

public Game(String s) {board = new StringBuffer(s);}

public Game(StringBuffer s, int position, char player) { board = new StringBuffer(); board.append(s); board.setCharAt(position, player); }

public int move(char player) { for (int i = 0; i < 9; i++) { if (board.charAt(i) == '-') { Game game = play(i, player); if (game.winner() == player) return i; } }

for (int i = 0; i < 9; i++) { if (board.charAt(i) == '-') return i; } return -1; }

A simple gameA simple game public Game play(int i, char player) { return new Game(this.board, i, player); }

public char winner() { if (board.charAt(0) != '-' && board.charAt(0) == board.charAt(1) && board.charAt(1) == board.charAt(2))

return board.charAt(0); if (board.charAt(3) != '-' && board.charAt(3) == board.charAt(4) && board.charAt(4) == board.charAt(5))

return board.charAt(3); if (board.charAt(6) != '-' && board.charAt(6) == board.charAt(7) && board.charAt(7) == board.charAt(8))

return board.charAt(6); return '-'; }}

A simple gameA simple game

int pos = new Game("XOXOX-OXO").move('X');

gameboard playerposition

char winner = new Game("XOXXX-OXO").winner();

winner's marker

A simple gameA simple game

Tasks Identify smells Suggest refactorings to remove the smells

merge loops simplify subsequent ifs name constants appropriately rework duplicates in winner() method mark '–' as empty square replace for loops with iterator provide extension points for scoring

Q&AQ&A