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MapReduce.php
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MapReduce.php
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<?php
/**
* PHP Version 5.4
*
* CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
* Copyright (c) Cake Software Foundation, Inc. (http://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. (http://cakefoundation.org)
* @link http://cakephp.org CakePHP(tm) Project
* @since CakePHP(tm) v 3.0.0
* @license MIT License (http://www.opensource.org/licenses/mit-license.php)
*/
namespace Cake\ORM;
use \IteratorAggregate;
use \ArrayIterator;
class MapReduce implements IteratorAggregate {
protected $_intermediate = [];
protected $_result = [];
protected $_executed = false;
protected $_data;
protected $_mapper;
protected $_reducer;
protected $_counter = 0;
public function __construct($data, array $routines) {
$this->_data = $data;
$this->_mapper = $routines['mapper'];
$this->_reducer = isset($routines['reducer']) ? $routines['reducer'] : null;
}
public function getIterator() {
if (!$this->_executed) {
$this->_execute();
}
return new ArrayIterator($this->_result);
}
public function emitIntermediate($key, $value) {
$this->_intermediate[$key][] = $value;
}
public function emit($value, $slot = null) {
$this->_result[$slot === null ? $this->_counter : $slot] = $value;
$this->_counter++;
}
protected function _execute() {
foreach ($this->_data as $key => $value) {
$this->_mapper->__invoke($key, $value, $this);
}
foreach ($this->_intermediate as $key => $list) {
$this->_reducer->__invoke($key, $list, $this);
}
$this->_execute = true;
}
}