Fabrique en PHP
La Fabrique est un patron de conception de création qui permet de créer des produits sans avoir à préciser leurs classes concrètes.
La fabrique définit une méthode qui doit être utilisée pour créer des objets à la place de l’appel au constructeur (opérateur new). Les sous-classes peuvent redéfinir cette méthode pour modifier la classe des objets qui seront créés.
Lisez notre Comparaison des fabriques si vous avez du mal à saisir la différence entre les divers concepts et patrons.
Complexité :
Popularité :
Exemples d’utilisation : La fabrique est très largement utilisée en PHP. Elle est très utile lorsque vous avez besoin de flexibilité dans votre code.
Identification : La fabrique peut être reconnue grâce à ses méthodes de création qui produisent des objets depuis les classes concrètes, mais les retournent en tant qu’objets d’interface ou de type abstrait.
Exemple conceptuel
Dans cet exemple, nous allons voir la structure de la Fabrique et répondre aux questions suivantes :
- Que contiennent les classes ?
- Quels rôles jouent-elles ?
- Comment les éléments du patron sont-ils reliés ?
Après avoir étudié la structure du patron, vous pourrez plus facilement comprendre l’exemple suivant qui est basé sur un cas d’utilisation réel en PHP.
index.php: Exemple conceptuel
<?php
namespace RefactoringGuru\FactoryMethod\Conceptual;
/**
* The Creator class declares the factory method that is supposed to return an
* object of a Product class. The Creator's subclasses usually provide the
* implementation of this method.
*/
abstract class Creator
{
/**
* Note that the Creator may also provide some default implementation of the
* factory method.
*/
abstract public function factoryMethod(): Product;
/**
* Also note that, despite its name, the Creator's primary responsibility is
* not creating products. Usually, it contains some core business logic that
* relies on Product objects, returned by the factory method. Subclasses can
* indirectly change that business logic by overriding the factory method
* and returning a different type of product from it.
*/
public function someOperation(): string
{
// Call the factory method to create a Product object.
$product = $this->factoryMethod();
// Now, use the product.
$result = "Creator: The same creator's code has just worked with " .
$product->operation();
return $result;
}
}
/**
* Concrete Creators override the factory method in order to change the
* resulting product's type.
*/
class ConcreteCreator1 extends Creator
{
/**
* Note that the signature of the method still uses the abstract product
* type, even though the concrete product is actually returned from the
* method. This way the Creator can stay independent of concrete product
* classes.
*/
public function factoryMethod(): Product
{
return new ConcreteProduct1();
}
}
class ConcreteCreator2 extends Creator
{
public function factoryMethod(): Product
{
return new ConcreteProduct2();
}
}
/**
* The Product interface declares the operations that all concrete products must
* implement.
*/
interface Product
{
public function operation(): string;
}
/**
* Concrete Products provide various implementations of the Product interface.
*/
class ConcreteProduct1 implements Product
{
public function operation(): string
{
return "{Result of the ConcreteProduct1}";
}
}
class ConcreteProduct2 implements Product
{
public function operation(): string
{
return "{Result of the ConcreteProduct2}";
}
}
/**
* The client code works with an instance of a concrete creator, albeit through
* its base interface. As long as the client keeps working with the creator via
* the base interface, you can pass it any creator's subclass.
*/
function clientCode(Creator $creator)
{
// ...
echo "Client: I'm not aware of the creator's class, but it still works.\n"
. $creator->someOperation();
// ...
}
/**
* The Application picks a creator's type depending on the configuration or
* environment.
*/
echo "App: Launched with the ConcreteCreator1.\n";
clientCode(new ConcreteCreator1());
echo "\n\n";
echo "App: Launched with the ConcreteCreator2.\n";
clientCode(new ConcreteCreator2());
Output.txt: Résultat de l’exécution
App: Launched with the ConcreteCreator1.
Client: I'm not aware of the creator's class, but it still works.
Creator: The same creator's code has just worked with {Result of the ConcreteProduct1}
App: Launched with the ConcreteCreator2.
Client: I'm not aware of the creator's class, but it still works.
Creator: The same creator's code has just worked with {Result of the ConcreteProduct2}
Analogie du monde réel
Dans cet exemple, la Fabrique fournit une interface pour créer des connecteurs pour les réseaux sociaux. Elle va pouvoir être utilisée pour se connecter au réseau, poster des messages et effectuer d’autres activités potentielles - et tout ceci sans coupler le code client aux classes concernant les réseaux sociaux.
index.php: Exemple du monde réel
<?php
namespace RefactoringGuru\FactoryMethod\RealWorld;
/**
* The Creator declares a factory method that can be used as a substitution for
* the direct constructor calls of products, for instance:
*
* - Before: $p = new FacebookConnector();
* - After: $p = $this->getSocialNetwork;
*
* This allows changing the type of the product being created by
* SocialNetworkPoster's subclasses.
*/
abstract class SocialNetworkPoster
{
/**
* The actual factory method. Note that it returns the abstract connector.
* This lets subclasses return any concrete connectors without breaking the
* superclass' contract.
*/
abstract public function getSocialNetwork(): SocialNetworkConnector;
/**
* When the factory method is used inside the Creator's business logic, the
* subclasses may alter the logic indirectly by returning different types of
* the connector from the factory method.
*/
public function post($content): void
{
// Call the factory method to create a Product object...
$network = $this->getSocialNetwork();
// ...then use it as you will.
$network->logIn();
$network->createPost($content);
$network->logout();
}
}
/**
* This Concrete Creator supports Facebook. Remember that this class also
* inherits the 'post' method from the parent class. Concrete Creators are the
* classes that the Client actually uses.
*/
class FacebookPoster extends SocialNetworkPoster
{
private $login, $password;
public function __construct(string $login, string $password)
{
$this->login = $login;
$this->password = $password;
}
public function getSocialNetwork(): SocialNetworkConnector
{
return new FacebookConnector($this->login, $this->password);
}
}
/**
* This Concrete Creator supports LinkedIn.
*/
class LinkedInPoster extends SocialNetworkPoster
{
private $email, $password;
public function __construct(string $email, string $password)
{
$this->email = $email;
$this->password = $password;
}
public function getSocialNetwork(): SocialNetworkConnector
{
return new LinkedInConnector($this->email, $this->password);
}
}
/**
* The Product interface declares behaviors of various types of products.
*/
interface SocialNetworkConnector
{
public function logIn(): void;
public function logOut(): void;
public function createPost($content): void;
}
/**
* This Concrete Product implements the Facebook API.
*/
class FacebookConnector implements SocialNetworkConnector
{
private $login, $password;
public function __construct(string $login, string $password)
{
$this->login = $login;
$this->password = $password;
}
public function logIn(): void
{
echo "Send HTTP API request to log in user $this->login with " .
"password $this->password\n";
}
public function logOut(): void
{
echo "Send HTTP API request to log out user $this->login\n";
}
public function createPost($content): void
{
echo "Send HTTP API requests to create a post in Facebook timeline.\n";
}
}
/**
* This Concrete Product implements the LinkedIn API.
*/
class LinkedInConnector implements SocialNetworkConnector
{
private $email, $password;
public function __construct(string $email, string $password)
{
$this->email = $email;
$this->password = $password;
}
public function logIn(): void
{
echo "Send HTTP API request to log in user $this->email with " .
"password $this->password\n";
}
public function logOut(): void
{
echo "Send HTTP API request to log out user $this->email\n";
}
public function createPost($content): void
{
echo "Send HTTP API requests to create a post in LinkedIn timeline.\n";
}
}
/**
* The client code can work with any subclass of SocialNetworkPoster since it
* doesn't depend on concrete classes.
*/
function clientCode(SocialNetworkPoster $creator)
{
// ...
$creator->post("Hello world!");
$creator->post("I had a large hamburger this morning!");
// ...
}
/**
* During the initialization phase, the app can decide which social network it
* wants to work with, create an object of the proper subclass, and pass it to
* the client code.
*/
echo "Testing ConcreteCreator1:\n";
clientCode(new FacebookPoster("john_smith", "******"));
echo "\n\n";
echo "Testing ConcreteCreator2:\n";
clientCode(new LinkedInPoster("john_smith@example.com", "******"));
Output.txt: Résultat de l’exécution
Testing ConcreteCreator1:
Send HTTP API request to log in user john_smith with password ******
Send HTTP API requests to create a post in Facebook timeline.
Send HTTP API request to log out user john_smith
Send HTTP API request to log in user john_smith with password ******
Send HTTP API requests to create a post in Facebook timeline.
Send HTTP API request to log out user john_smith
Testing ConcreteCreator2:
Send HTTP API request to log in user john_smith@example.com with password ******
Send HTTP API requests to create a post in LinkedIn timeline.
Send HTTP API request to log out user john_smith@example.com
Send HTTP API request to log in user john_smith@example.com with password ******
Send HTTP API requests to create a post in LinkedIn timeline.
Send HTTP API request to log out user john_smith@example.com
