Refactoring and other small animals

Transcription

1 Refactoring and other small animals Marco

2 What we ll cover What is refactoring Why refactoring is important When to refactor How to refactor safely

3 Show of Hands Do you use refactoring?

4 Refactoring is the process of changing a software system in such a way that it does not alter the external behaviour of the code yet improves its internal structure. Martin Fowler

5 Refactoring is the process of changing a software system in such a way that it does not alter the external behaviour of the code yet improves its internal structure.

6 Refactoring is the process of changing a software system in such a way that it does not alter the external behaviour of the code yet improves its internal structure.

7 Refactoring is the process of changing a software system in such a way that it does not alter the external behaviour of the code yet improves its internal structure.

8 Change

9 Consistency

10 Improvement

11 Good reasons to refactor

12 Good reasons to refactor Code smells Functionality smells Too much code! Futureproofing

13 Good reasons to refactor Code smells Functionality smells Too much code! Futureproofing

14 Good reasons to refactor Code smells Functionality smells Too much code! Futureproofing

15 Good reasons to refactor Code smells Functionality smells Too much code! Futureproofing

16 Good reasons to refactor Code smells Functionality smells Extensibility Futureproofing

17 Good reasons to refactor Code smells Functionality smells Extensibility Futureproofing

18 Good reasons to refactor Code smells Functionality smells Extensibility Maintainability

19 How do you refactor?

20 Well

21 Before you refactor

22 Test!

23 So, about those refactoring techniques

24 So, about those refactoring techniques Abstract Break (apart) Rename

25 So, about those refactoring techniques Abstract Break (apart) Rename

26 So, about those refactoring techniques Abstract Break (apart) Rename

27 So, about those refactoring techniques Abstract Break (apart) Rename

28 Some Examples Renaming Encapsulation Type generalization <?php class Codeworks { function dosomething() {... State/Strategy type replacement

29 Some Examples Renaming Encapsulation Type generalization <?php class Codeworks { function loaddatafromserver() {... State/Strategy type replacement

30 Some Examples Renaming Encapsulation <?php class AClass { public $x; Type generalization State/Strategy type replacement

31 Some Examples Renaming Encapsulation Type generalization <?php class AClass { protected $_x; public function get($name) { if ($name == 'x') {... State/Strategy type replacement public function set($name, $value) { if ($name == 'x') {...

32 Some Examples Renaming Encapsulation Type generalization State/Strategy type replacement <?php class Cal { function isontime() { return 'Always, or die trying'; class Marco { function isontime() { return 'Sometimes'; class Arbi { function isontime() { throw new Exception("Where's Arbi?");

33 Some Examples Renaming Encapsulation Type generalization State/Strategy type replacement <?php interface BlueParabola { function isontime(); class Cal implements BlueParabola { function isontime() { return 'Always, or die trying'; class Marco implements BlueParabola { function isontime() { return 'Sometimes'; class Arbi implements BlueParabola { function isontime() { throw new Exception("Where's Arbi?");

34 Some Examples Renaming Encapsulation Type generalization State/Strategy type replacement <?php class Computer { const WINDOWS = 1; const MAC = 2; const LINUX = 3; public $_type; function getcost() { switch ($this->type) { case Computer::WINDOWS: return 'medium'; case Computer::MAC: return 'high'; case Computer::LINUX: return 'low';

35 Some Examples Renaming Encapsulation Type generalization State/Strategy type replacement <?php interface ComputerType { function getcost(); function gettype(); class Windows implements ComputerType { function getcost() { return 'medium'; function gettype() { return Computer::WINDOWS; class Computer {... protected $_type; function set($name, $value) { if ($name == 'type') { switch ($value) { case Computer::WINDOWS: $this->_type = new Windows; function get($name) { if ($name == 'type') { return $this->_type->gettype(); function getcost() { return $this->_type->getcost();

36 Change Consistency Improvement

37 Refuctoring

38 Beware the Ides of March Bill Shakespeare

39 Beware the IDEs Me

40 @mtabini