* @link http://www.yiiframework.com/
* @copyright Copyright © 2008-2012 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CDataProviderIterator allows iteration over large data sets without holding the entire set in memory.
*
* CDataProviderIterator iterates over the results of a data provider, starting at the first page
* of results and ending at the last page. It is usually only suited for use with CActiveDataProvider.
*
* For example, the following code will iterate through all registered users without
* running out of memory, even if there are millions of users in the database.
*
* $dataProvider = new CActiveDataProvider("User");
* $iterator = new CDataProviderIterator($dataProvider);
* foreach($iterator as $user) {
* echo $user->name."\n";
* }
*
*
* @property array $items the currently loaded items
* @property integer $currentIndex the 0 based current index
* @property integer $totalItems the total number of items in the iterator
*
* @author Charles Pick
* @package system.web
* @since 1.1.11
*/
class CDataProviderIterator implements Iterator, Countable
{
/**
* The data provider to iterate over
* @var CDataProvider
*/
public $dataProvider;
/**
* The current index
* @var integer
*/
protected $_currentIndex = -1;
/**
* The current page in the pagination
* @var integer
*/
protected $_currentPage = 0;
/**
* The total number of items
* @var integer
*/
protected $_totalItems = -1;
/**
* The current set of items
* @var array
*/
protected $_items;
/**
* Constructor. Sets the data provider to iterator over
* @param CDataProvider $dataProvider the data provider to iterate over
*/
public function __construct(CDataProvider $dataProvider)
{
$this->dataProvider = $dataProvider;
$this->_totalItems = $dataProvider->getTotalItemCount();
}
/**
* Sets the current index position
* @param integer $currentIndex the current index positon
*/
public function setCurrentIndex($currentIndex)
{
$this->_currentIndex = $currentIndex;
}
/**
* Gets the zero based current index position
* @return integer index position
*/
public function getCurrentIndex()
{
return $this->_currentIndex;
}
/**
* Gets the current set of items to iterate over
* @return array the current set items to iterate over
*/
public function getItems()
{
return $this->_items;
}
/**
* Sets the total number of items to iterate over
* @param int $totalItems the total number of items to iterate over
*/
public function setTotalItems($totalItems)
{
$this->_totalItems = $totalItems;
}
/**
* Gets the total number of items to iterate over
* @return integer the total number of items to iterate over
*/
public function getTotalItems()
{
return $this->_totalItems;
}
/**
* Loads the page of results
* @return array the items from the next page of results
*/
protected function loadPage()
{
$this->dataProvider->getPagination()->setCurrentPage($this->_currentPage);
return $this->_items = $this->dataProvider->getData(true);
}
/**
* Gets the current item in the list.
* This method is required by the Iterator interface
* @return mixed the current item in the list
*/
public function current()
{
$items = $this->getItems();
return $items[$this->getCurrentIndex()];
}
/**
* Gets the key of the current item.
* This method is required by the Iterator interface
* @return integer the key of the current item
*/
public function key()
{
$pagination = $this->dataProvider->getPagination();
$currentPage = $this->_currentPage;
$pageSize = $pagination->getPageSize();
return $currentPage * $pageSize + $this->getCurrentIndex();
}
/**
* Moves the pointer to the next item in the list.
* This method is required by the Iterator interface
*/
public function next()
{
$pagination = $this->dataProvider->getPagination();
$this->_currentIndex++;
if ($this->getCurrentIndex() >= $pagination->getPageSize()) {
$this->_currentPage++;
$this->_currentIndex = 0;
$this->loadPage();
}
}
/**
* Rewinds the iterator to the start of the list.
* This method is required by the Iterator interface
*/
public function rewind()
{
$this->_currentIndex = 0;
$this->_currentPage = 0;
$this->loadPage();
}
/**
* Checks if the current position is valid or not.
* This method is required by the Iterator interface
* @return boolean true if this index is valid
*/
public function valid()
{
return $this->key() < $this->getTotalItems();
}
/**
* Gets the total number of items in the dataProvider
* This method is required by the Countable interface
* @return integer the total number of items
*/
public function count()
{
return $this->getTotalItems();
}
}