<?php
/**
* CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
* Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
*
* Licensed under The MIT License
* For full copyright and license information, please see the LICENSE.txt
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
* @link https://cakephp.org CakePHP(tm) Project
* @since 3.0.0
* @license https://opensource.org/licenses/mit-license.php MIT License
*/
namespace Cake\Collection\Iterator;
use IteratorIterator;
use RecursiveIterator;
/**
* An iterator that can be used to generate nested iterators out of a collection
* of items by applying an function to each of the elements in this iterator.
*
* @internal
* @see \Cake\Collection\Collection::unfold()
*/
class UnfoldIterator extends IteratorIterator implements RecursiveIterator
{
/**
* A function that is passed each element in this iterator and
* must return an array or Traversable object.
*
* @var callable
*/
protected $_unfolder;
/**
* A reference to the internal iterator this object is wrapping.
*
* @var \Iterator
*/
protected $_innerIterator;
/**
* Creates the iterator that will generate child iterators from each of the
* elements it was constructed with.
*
* @param array|\Traversable $items The list of values to iterate
* @param callable $unfolder A callable function that will receive the
* current item and key. It must return an array or Traversable object
* out of which the nested iterators will be yielded.
*/
public function __construct($items, callable $unfolder)
{
$this->_unfolder = $unfolder;
parent::__construct($items);
$this->_innerIterator = $this->getInnerIterator();
}
/**
* Returns true as each of the elements in the array represent a
* list of items
*
* @return bool
*/
public function hasChildren()
{
return true;
}
/**
* Returns an iterator containing the items generated by transforming
* the current value with the callable function.
*
* @return \RecursiveIterator
*/
public function getChildren()
{
$current = $this->current();
$key = $this->key();
$unfolder = $this->_unfolder;
return new NoChildrenIterator($unfolder($current, $key, $this->_innerIterator));
}
}