Manage your objects

Après une discution animée autour de concepts objets lors du dernier Apéro PHP de Montpellier, je me suis aperçu qu'un petit rappel des bases de la POO était nécessaire.

En 10 minutes, retour sur des concepts comme l'Injection de dépendances et sur certains design patterns (factory, singleton).

Le tout illustré avec des exemples en PHP.

Transcript

1. Manage your objects thomas@gasc.fr @methylbro Tuesday 9th of September 2014 Montpellier
2. Case study /* ask name */ fwrite(STDOUT, "enter your name :"); $name = trim(fgets(STDIN, 255)); /* ask birthday */ fwrite(STDOUT, "enter your birthday (yyyy/mm/dd) :"); $birthday = new DateTime(trim(fgets(STDIN, 255))); /* calculate the age */ $age = $birthday->diff(new DateTime()); /* display the result */ fwrite( STDOUT, sprintf(PHP_EOL."hello %s you've got %s years old.", $name, $age->y) );
3. Oriented Object Programing
4. Application Class Diagram Reader + handle + length + read(msg) Writer + handle + write(msg) AgeCalculator + execute()
5. // src/Reader.php class Reader { private $handle = STDIN; private $length = 255; private $writer; public function __construct() { $this->writer = new Writer(); } public function read($msg) { $this->writer->write($msg); return trim(fgets($this->handle, $this->length)); } }
6. // src/AgeCalculator.php class AgeCalculator { private $reader, $writer; public function __construct() { $this->reader = new Reader(); $this->writer = new Writer(); } public function execute() { $name = $this->reader->read('your name:'); $birthday = new DateTime( $this->reader->read('your birthday (yyyy/mm/dd):') ); $age = $birthday->diff(new DateTime('now')); $this->writer->write( sprintf("hello %s you've got %s years old.", $name, $age->y) ); } }
7. Running the application // age-calculator.php $ageCalculator = new AgeCalculator(); $ageCalculator->execute(); $ php age-calculator.php your name: thomas your birthday (yyyy/mm/dd): 1994/01/01 hello thomas you've got 20 years old.
8. Dependency Injection Pass a dependency to a dependent object
9. // src/Reader.php class Reader { private $handle, $length, $writer; public function __construct(Writer $writer = null, $handle = STDIN, $length = 255) { $this->handle = $handle; $this->length = $length; $this->writer = $writer; } public function read($msg) { if ($this->writer) { $this->writer->write($msg); } return trim(fgets($this->handle, $this->length)); } }
10. // age-calculator.php $writer = new Writer(); $reader = new Reader($writer); $ageCalculator = new AgeCalculator($writer, $reader); $ageCalculator->execute();
11. // age-calculator.php $writer = new Writer(fopen('result', 'w+')); $reader = new Reader(null, fopen('data', 'r')); $ageCalculator = new AgeCalculator($writer, $reader); $ageCalculator->execute();
12. Using a Dependency Injection Framework
13. // config/cli.php return [ 'Writer' => DI\object()->constructor(), 'Reader' => DI\object() ->constructor(DI\link('Writer')), 'AgeCalculator' => DI\object() ->constructor(DI\link('Writer'), DI\link('Reader')), ];
14. // age-calculator.php require 'vendor/autoload.php'; $builder = new \DI\ContainerBuilder(); $builder->addDefinitions('config/cli.php'); $container = $builder->build(); $ageCalculator = $container->get('AgeCalculator'); $ageCalculator->execute();
15. // config/file.php return [ 'handle.result' => fopen('result', 'w+'), 'handle.data' => fopen('data', 'r'), 'Writer' => DI\object() ->constructor(DI\link('handle.result')), 'Reader' => DI\object() ->constructor(null, DI\link('handle.data')), 'AgeCalculator' => DI\object() ->constructor(DI\link('Writer'), DI\link('Reader')), ];
16. Factory Design Pattern Deals with the problem of creating objects without specifying the exact class of object that will be created
17. << abstract >> Factory + create() WriterFactory ReaderFactory FileWriter Writer Reader FileReader << interface >> ReaderInterface << interface >> WriterInterface creates creates extends extends extends extends uses extends extends + setWriter(writer) + read(msg) + write(msg)
18. // src/FileWriter.php class FileWriter extends Writer { public function __construct($filename, $length = 255) { $this->handle = fopen($filename, 'w+'); $this->length = $length; } } // src/Filereader.php class FileReader extends Reader { public function __construct($filename, $length = 255) { $this->handle = fopen($filename, 'r'); $this->length = $length; } }
19. // src/Factory.php abstract class Factory { private $class; public function __construct($class) { $this->class = new ReflectionClass($class); } protected abstract function configure(ReflectionClass $class); public function create($args = array()) { return $this->class->newInstanceArgs($args); } }
20. // config/file.php return [ 'writer.class' => 'FileWriter', 'reader.class' => 'FileReader', 'data.file' => 'data', 'result.file' => 'result', 'WriterFactory' => DI\object()->constructor(DI\link('writer.class')), 'ReaderFactory' => DI\object() ->constructor( DI\link('reader.class')), DI\factory(function ($container) { return $container ->get('WriterFactory') ->create(array($container->get('result.file'))) ; }), DI\factory(function ($container) { return $container ->get('ReaderFactory') ->create(array($container->get('data.file'))) ; } ), 'AgeCalculator' => DI\object()->constructor(DI\link('writer'), DI\link('reader')), ];
21. Singleton Design Pattern Restricts the instantiation of a class to one object
22. Singleton
23. Full examples https://github.com/methylbro/human-talk-manage-objects-examples Questions ?