Design Patterns: Iterator en PHP

Iterator est un design pattern qui permet de parcourir une structure de données complexe sans exposer ses détails internes.

Le pattern Iterator est très courant en PHP. De nombreux frameworks et bibliothèques l’utilisent pour fournir un moyen standard de parcourir leurs collections.
 
 

Exemple :

La classe « Car »

<?php

class Car
{
    private string $name;
    private string $model;

    public function __construct(string $name, string $model)
    {
        $this->name = $name;
        $this->model = $model;
    }

    public function getName(): string
    {
        return $this->name;
    }

    public function getModel(): string
    {
        return $this->model;
    }

    public function getNameAndModel(): string
    {
        return $this->getName().' & '.$this->getModel();
    }
}

?>

La classe « Car »

<?php

class CarListIterator implements \Countable, \Iterator
{
    private array $cars = [];
    private int $i = 0;

    public function addCar(Car $car)
    {
        $this->cars[] = $car;
    }

    public function removeCar(Car $car_in)
    {
        foreach ($this->cars as $key => $car) {
            if ($car->getNameAndModel() === $car_in->getNameAndModel()) {
                unset($this->cars[$key]);
            }
        }

        $this->cars = array_values($this->cars);
    }

    public function count(): int
    {
        return count($this->cars);
    }

    public function current(): Car
    {
        return $this->cars[$this->i];
    }

    public function key(): int
    {
        return $this->i;
    }

    public function next()
    {
        $this->i++;
    }

    public function rewind()
    {
        $this->i = 0;
    }

    public function valid(): bool
    {
        return isset($this->cars[$this->i]);
    }
}
?>

Code de test:

$carList = new CarListIterator();
$carList->addCar(new Car('Audi', 'A7'));
$carList->addCar(new Car('Bmw', 'X25'));
$carList->addCar(new Car('Mercedes', 'Classe C'));

$cars = [];

foreach ($carList as $car) {
	$cars[] = $car->getNameAndModel();
}

 
Sortie:

Audi & A7
Bmw & X25
Mercedes & Classe C