Many people teach design patterns as a fundamental step to Object Oriented Programming. They are so universally seen as important that almost every single programming conference that I have been to has had at least one talk about them. They are quite often used as interview questions to test a candidate's OOP knowledge. However, just like inheritance, they are not needed for OOP. And just like inheritance, they are a distraction rather than a foundation. Instead of focusing on patterns, I suggest focusing on learning about abstraction and communication. Why? Come and find out! Talk at #PHPNW14

1. Beyond Design Patterns
A Guide To Better OOP

2. OR:
Why Learning
Object-Oriented
Design From Design
Patterns Is Bad

3. Object Oriented Design
… is the process of planning a
system of interacting objects
for the purpose of solving a
software problem.
-Wikipedia

4. What Are Design
Patterns?

5. What Are Design
Patterns?
● Commonly Occurring Solutions?

6. What Are Design
Patterns?
● Commonly Occurring Solutions?
● Commonly Occurring Structures?

7. What Are Design
Patterns?
● Commonly Occurring Solutions?
● Commonly Occurring Structures?
● Commonly Occurring Limitations?

8. What Are Design
Patterns?
● Commonly Occurring Solutions?
● Commonly Occurring Structures?
● Commonly Occurring Limitations?
● All Of The Above?

9. What Are Design
Patterns?
All Of The Above!

10. What Kind Of Design
Patterns Are There?

11. Gang-Of-Four Design Patterns
Creational
Abstract Factory
Builder
Factory Method
Object Pool
Prototype

12. Gang-Of-Four Design Patterns
Creational Structural
Abstract Factory
Builder
Factory Method
Object Pool
Prototype
Adapter
Bridge
Composite
Decorator
Facade
Flyweight
Proxy

13. Gang-Of-Four Design Patterns
Creational Structural Behavioral
Abstract Factory
Builder
Factory Method
Object Pool
Prototype
Adapter
Bridge
Composite
Decorator
Facade
Flyweight
Proxy
Chain Of Responsibility
Command
Interpreter
Iterator
Mediator
Memento
Null Object
Observer
Strategy
Template Method

14. Let’s Try A Different
Organization

15. Gang-Of-Four Design Patterns
Shim
Flyweight
Iterator
Null Object
Object Pool
Prototype
Re-Grouped

16. Gang-Of-Four Design Patterns
Re-Grouped
Shim Compositional
Flyweight
Iterator
Null Object
Object Pool
Prototype
Adapter
Builder
Decorator
Facade
Interpreter
Mediator
Observer
Proxy

17. Gang-Of-Four Design Patterns
Re-Grouped
Shim Compositional Decompositional
Flyweight
Iterator
Null Object
Object Pool
Prototype
Adapter
Builder
Decorator
Facade
Interpreter
Mediator
Observer
Proxy
Abstract Factory
Bridge
Chain Of Responsibility
Command
Factory Method
Mediator
Memento
Observer
Proxy
Strategy
Template Method

18. Compare Groupings
Creational Structural Behavioral
Shim Abstract Factory
Object Pool
Prototype
Flyweight Iterator
Null Object
Compositional Builder Adapter
Composite
Decorator
Facade
Proxy
Interpreter
Mediator
Observer
Decompositional Factory Method Bridge
Composite
Proxy
Chain Of Responsibility
Command
Mediator
Memento
Observer
Strategy
Template Method

19. Let’s Examine 5 Patterns
More Closely

20. Compare Groupings
Creational Structural Behavioral
Shim Abstract Factory
Object Pool
Prototype
Flyweight Iterator
Null Object
Compositional Builder Adapter
Composite
Decorator
Facade
Proxy
Interpreter
Mediator
Observer
Decompositional Factory Method Bridge
Composite
Proxy
Chain Of Responsibility
Command
Mediator
Memento
Observer
Strategy
Template Method

21. Adapter
use PsrLogLoggerInterface as Log
class PSR3Logger implements Log {
public function log($level, $msg, array $ctx = array())
{
$severity = $this->convertLevelToSeverity($level);
watchdog(“unknown”, $msg, $ctx, $severity);
}
/* ... */
}

22. Facade
class EntityMetadataWrapper {
public function __construct($type, $data = null, $info = array()) {
$this->type = $type;
$this->info = $info + array(
“langcode” => null,
);
$this->info[“type”] = $type;
if (isset($data)) {
$this->set($data);
}
}
/* ... */
}

23. Adapter vs Facade
Class 1
Class 2
Class 3
Class n
Class 1
Class m
Existing
Code
Other
Code
“Pattern”
Code Class 1
Class 2
Class 3
Class n
API

24. Adapter vs Facade
Class 1
Class 2
Class 3
Class n
Class 1
Class m
Existing
Code
Other
Code
“Pattern”
Code Class 1
Class 2
Class 3
Class n
API API Exists? Adapter

25. Adapter vs Facade
Class 1
Class 2
Class 3
Class n
Class 1
Class m
Existing
Code
Other
Code
“Pattern”
Code Class 1
Class 2
Class 3
Class n
API API Exists? Adapter
New API? Facade

26. They Look The
Same!!!???

27. Adapter Facade
Bridge Decorator Proxy

28. They All Look The
Same!!!???

29. Adapter Facade
Bridge Decorator Proxy

30. Adapter Facade
The Code Is The Same
The Why Is Different
Bridge Decorator Proxy

31. DeDuplicated Groupings
Creational Structural Behavioral
Compositional Adapter
Composite
Mediator
Observer
Decompositional Adapter
Composite
Command
Mediator
Memento
Observer

32. DeDuplicated Re-Groupings
Multiple
Systems?
Single
System?
Single
Objects?
Information
Flow?
Mediator Command Observer
Structure Adapter Composite Memento

33. DeDeDuplicated Re-Groupings
Pattern
Information
Flow?
Mediator
Structure Adapter

34. DeDeDuplicated ReRe-Groupings
Pattern
Information
Flow?
Mediator

35. All Design Patterns Do
The Same Thing:

36. All Design Patterns Do
The Same Thing:
Control Information Flow

37. So Let’s Talk About
Information Flow

38. So Let’s Talk About
Communication

39. A message
$msg

40. Logic
$obj

41. Message Vs Logic
State

42. Message Vs Logic
Messages
State

43. Message Vs Logic
Messages
State
Logic

44. Message Vs Logic
Messages
State
Logic HERE BE
DRAGONS

45. Why Break Them Apart?
Logic Hybrid Message
Purpose Behavior General Code State
State Stateless Stateful Stateful
Paradigm Functional OOP? Data

46. Ask
$msg = $obj->something();
Logic Hybrid Message
No Yes Yes

47. Tell
$obj->something($msg);
Logic Hybrid Message
No Yes Yes

48. Translate
$msg2 = $obj->do($msg);
Logic Hybrid Message
Yes Yes No

49. Everything Else Is A
Combination Of These
Atoms

50. Note:

51. Note:
Ask Is Always Stateful

52. Note:
Ask Is Always Stateful
Tell Is Always Stateful

53. Note:
Ask Is Always Stateful
Tell Is Always Stateful
Translate Can Be Stateless

54. Why Does This Matter?

55. It Lets Us Analyze
Object Roles

56. Object Role Patterns
State? Logic? Mode

57. Object Role Patterns
State? Logic? Mode
Representer User No Ask/Tell

58. Representer
class User {
public function getName();
public function isAdmin();
public function setName($name);
}

59. Object Role Patterns
State? Logic? Mode
Representer User No Ask/Tell
Doer No Yes Tell

60. Doer
class EmailSystem {
/**
* @return boolean
*/
public function send(Message $msg);
}

61. Object Role Patterns
State? Logic? Mode
Representer User No Ask/Tell
Doer No Yes Tell
Dispatcher System No Translate

62. Dispatcher
class Controller {
/**
* @return Response
*/
public function handle(Request $req);
}

63. Object Role Patterns
State? Logic? Mode
Representer User No Ask/Tell
Doer No Yes Tell
Dispatcher System No Translate
Translator No Yes Translate

64. Translator
class UserView {
/**
* @return string HTML
*/
public function render(User $user);
}

65. Object Role Patterns
State? Logic? Mode
Representer User No Ask/Tell
Doer No Yes Tell
Dispatcher System No Translate
Translator No Yes Translate
Maker System Yes Ask

66. Makers
class UserFactory {
/**
* @return User a user object
*/
public function getUser();
}

67. Object Role Patterns
State? Logic? Mode
Representer User No Ask/Tell
Doer No Yes Tell
Dispatcher System No Translate
Translator No Yes Translate
Maker System Yes Ask

68. Object Role Patterns
Representer
Doer
Dispatcher
Translator
Maker

69. Object Oriented Design
… is the process of planning a
system of interacting objects
for the purpose of solving a
software problem.
-Wikipedia

70. Object Oriented Design
… is the process of planning a
system of interacting objects
for the purpose of solving a
software problem.
-Wikipedia

71. Design Patterns
Are Important!
And Should Be Used!

72. But OOP Is Not About
“Finding The Correct
Pattern”

73. Focus on:
Communication
Interaction
And Abstraction

74. Remember:
OOP Is About
Solving Problems

75. Anthony Ferrara
joind.in/11796
@ircmaxell
me@ircmaxell.com
blog.ircmaxell.com
github.com/ircmaxell
youtube.com/ircmaxell