beyond design patterns phpnw14

Beyond Design PatternsA Guide To Better OOP

Why Learning Object-Oriented

Design From Design Patterns Is Bad

OR:

Object Oriented Design

… is the process of planning a system of interacting objects for the purpose of solving a software problem.

-Wikipedia

What Are Design Patterns?

What Are Design Patterns?

● Commonly Occurring Solutions?

What Are Design Patterns?

● Commonly Occurring Solutions?● Commonly Occurring Structures?

What Are Design Patterns?

● Commonly Occurring Solutions?● Commonly Occurring Structures?● Commonly Occurring Limitations?

What Are Design Patterns?

● Commonly Occurring Solutions?● Commonly Occurring Structures?● Commonly Occurring Limitations?

● All Of The Above?

What Are Design Patterns?

All Of The Above!

What Kind Of Design Patterns Are There?

Creational

Abstract FactoryBuilderFactory MethodObject PoolPrototype

Gang-Of-Four Design Patterns

Creational Structural

Abstract FactoryBuilderFactory MethodObject PoolPrototype

AdapterBridgeCompositeDecoratorFacadeFlyweightProxy

Gang-Of-Four Design Patterns

Creational Structural Behavioral

Abstract FactoryBuilderFactory MethodObject PoolPrototype

AdapterBridgeCompositeDecoratorFacadeFlyweightProxy

Chain Of ResponsibilityCommandInterpreterIteratorMediatorMementoNull ObjectObserverStrategyTemplate Method

Gang-Of-Four Design Patterns

Let’s Try A Different Organization

Shim

FlyweightIteratorNull ObjectObject PoolPrototype

Gang-Of-Four Design PatternsRe-Grouped

Shim Compositional

FlyweightIteratorNull ObjectObject PoolPrototype

AdapterBuilderDecoratorFacadeInterpreterMediatorObserverProxy

Gang-Of-Four Design PatternsRe-Grouped

Shim Compositional Decompositional

FlyweightIteratorNull ObjectObject PoolPrototype

AdapterBuilderDecoratorFacadeInterpreterMediatorObserverProxy

Abstract FactoryBridgeChain Of ResponsibilityCommandFactory MethodMediatorMementoObserverProxyStrategyTemplate Method

Gang-Of-Four Design PatternsRe-Grouped

Compare Groupings

Creational Structural Behavioral

Shim Abstract FactoryObject PoolPrototype

Flyweight IteratorNull Object

Compositional Builder AdapterCompositeDecoratorFacadeProxy

InterpreterMediatorObserver

Decompositional Factory Method BridgeCompositeProxy

Chain Of ResponsibilityCommandMediatorMementoObserverStrategyTemplate Method

Let’s Examine 5 Patterns More Closely

Compare Groupings

Creational Structural Behavioral

Shim Abstract FactoryObject PoolPrototype

Flyweight IteratorNull Object

Compositional Builder AdapterComposite

DecoratorFacadeProxy

InterpreterMediatorObserver

Decompositional Factory Method BridgeComposite

Proxy

Chain Of ResponsibilityCommandMediatorMementoObserverStrategyTemplate Method

Adapter

use Psr\Log\LoggerInterface as Logclass PSR3Logger implements Log {

public function log($level, $msg, array $ctx = array()) {

$severity = $this->convertLevelToSeverity($level);

watchdog(“unknown”, $msg, $ctx, $severity);

}

/* ... */

}

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);

}

}

/* ... */

}

Adapter vs Facade

Class 1

Class 2

Class 3

Class n

Class 1

Class m

ExistingCode

“Pattern”Code Class 1

Class 2

Class 3

Class n

OtherCode

API

Adapter vs Facade

Class 1

Class 2

Class 3

Class n

Class 1

Class m

ExistingCode

“Pattern”Code Class 1

Class 2

Class 3

Class n

OtherCode

API

API Exists? Adapter

Adapter vs Facade

Class 1

Class 2

Class 3

Class n

Class 1

Class m

ExistingCode

“Pattern”Code Class 1

Class 2

Class 3

Class n

OtherCode

API

API Exists? AdapterNew API? Facade

They Look The Same!!!???

Adapter Facade

Bridge Decorator Proxy

They All Look The Same!!!???

Adapter Facade

Bridge Decorator Proxy

Adapter Facade

Bridge Decorator Proxy

The Code Is The SameThe Why Is Different

DeDuplicated Groupings

Creational Structural Behavioral

Compositional AdapterComposite

MediatorObserver

Decompositional AdapterComposite

CommandMediatorMementoObserver

DeDuplicated Re-Groupings

Multiple Systems?

Single System?

Single Objects?

Information Flow?

Mediator Command Observer

Structure Adapter Composite Memento

DeDeDuplicated Re-Groupings

Pattern

Information Flow?

Mediator

Structure Adapter

DeDeDuplicated ReRe-Groupings

Pattern

Information Flow?

Mediator

All Design Patterns Do The Same Thing:

All Design Patterns Do The Same Thing:

Control Information Flow

So Let’s Talk About Information Flow

So Let’s Talk About Communication

$msg

A message

$obj

Logic

Message Vs Logic

State

Message Vs Logic

Messages

State

Message Vs Logic

Messages

State

Logic

Message Vs Logic

Messages

State

Logic HERE BE DRAGONS

Why Break Them Apart?

Logic Hybrid Message

Purpose Behavior General Code State

State Stateless Stateful Stateful

Paradigm Functional OOP? Data

$msg = $obj->something();

Ask

Logic Hybrid Message

No Yes Yes

$obj->something($msg);

Tell

Logic Hybrid Message

No Yes Yes

$msg2 = $obj->do($msg);

Translate

Logic Hybrid Message

Yes Yes No

Everything Else Is A Combination Of These

Atoms

Note:

Ask Is Always Stateful

Note:

Ask Is Always StatefulTell Is Always Stateful

Note:

Ask Is Always StatefulTell Is Always Stateful

Translate Can Be Stateless

Note:

Why Does This Matter?

It Lets Us Analyze Object Roles

Object Role Patterns

State? Logic? Mode

Object Role Patterns

State? Logic? Mode

Representer User No Ask/Tell

Representer

class User {

public function getName();

public function isAdmin();

public function setName($name);

}

Object Role Patterns

State? Logic? Mode

Representer User No Ask/Tell

Doer No Yes Tell

Doer

class EmailSystem {

/** * @return boolean */ public function send(Message $msg);

}

Object Role Patterns

State? Logic? Mode

Representer User No Ask/Tell

Doer No Yes Tell

Dispatcher System No Translate

Dispatcher

class Controller {

/** * @return Response */ public function handle(Request $req);

}

Object Role Patterns

State? Logic? Mode

Representer User No Ask/Tell

Doer No Yes Tell

Dispatcher System No Translate

Translator No Yes Translate

Translator

class UserView {

/** * @return string HTML */ public function render(User $user);

}

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

Makers

class UserFactory {

/** * @return User a user object */ public function getUser();

}

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

Object Role Patterns

Representer

Doer

Dispatcher

Translator

Maker

Object Oriented Design

… is the process of planning a system of interacting objects for the purpose of solving a software problem.

-Wikipedia

Object Oriented Design

… is the process of planning a system of interacting objects for the purpose of solving a software problem.

-Wikipedia

Design PatternsAre Important!

And Should Be Used!

But OOP Is Not About “Finding The Correct

Pattern”

Focus on:Communication

InteractionAnd Abstraction

Remember:OOP Is About

Solving Problems

Anthony Ferrarajoind.in/11796

@ircmaxellme@ircmaxell.comblog.ircmaxell.com

github.com/ircmaxellyoutube.com/ircmaxell