class AuthorCollectionIterator

class AuthorCollectionIterator implements Iterator {
    
    /** @var Author[] */
    private $authors;
    
    /** @var int */
    private $position = 0;
    public function __construct(AuthorCollection $authors) {
        $this->authors = $authors->getAuthors();
    }
    public function rewind() : void {
        $this->position = 0;
    }
    public function valid() : bool {
        return $this->position < count($this->authors);
    }
    public function key() : int {
        return $this->position;
    }
    public function current() : Author {
        return $this->authors[$this->position];
    }
    public function next() : void {
        $this->position++;
    }

}