<?php
class BookShelfIterator implements YIterator
{
	private $bookshelf;
	private $index;
	public function __construct( &$bookshelf ) {
		$this->bookshelf = $bookshelf;
		$this->index = 0;
	}
	public function hasNext() {
		if ($this->index < $this->bookshelf->getLength()) {
			return true;
		} else {
			return false;
		}
	}
	public function & next() {
		$book = $this->bookshelf->getBookAt($this->index);
		$this->index++;
		return $book;
	}	
}
?>