The an example observer design pattern in php

test.php

<?php


interface Subscriber
{
    public function handle(Blog $blog): void;
}

trait ObserveAble
{
    private array $events;

    public function share(Subscriber $subscriber): self
    {
        $this->events[] = $subscriber;
        return $this;
    }

    private function notify(Blog $blog): void
    {
        foreach ($this->events as $handler) {
            $handler->handle($blog);
        }
    }
}

class Blog
{

    public function __construct(private readonly int $id, private readonly string $name)
    {
    }

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

    /**
     * @return int
     */
    public function getId(): int
    {
        return $this->id;
    }

}

class Facebook implements Subscriber
{

    public function handle(Blog $blog): void
    {

        echo sprintf(
            'id: %d, name: %s will share on facebook',
            $blog->getId(),
            $blog->getName()
        );
    }
}

class Linkedin implements Subscriber
{

    public function handle(Blog $blog): void
    {
        echo sprintf(
            'id: %d, name: %s will share on linkedin',
            $blog->getId(),
            $blog->getName()
        );
    }
}

class Article
{
    use ObserveAble;

    public function publish(): bool
    {
        $this->notify(new Blog(12, 'test article'));
        return true;
    }
}


$article = new Article();
$article
    ->share(new Facebook())
    ->share(new Linkedin());

$article->publish();