* @link http://www.yiiframework.com/
* @copyright 2008-2013 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 {@link CActiveDataProvider}.
*
* For example, the following code will iterate over all registered users (active record class User) 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 CDataProvider $dataProvider the data provider to iterate over
* @property integer $totalItemCount the total number of items in the iterator
*
* @author Charles Pick
* @author Carsten Brandt
* @package system.web
* @since 1.1.13
*/
class CDataProviderIterator extends CComponent implements Iterator, Countable
{
private $_dataProvider;
private $_currentIndex=-1;
private $_currentPage=0;
private $_totalItemCount=-1;
private $_items;
/**
* Constructor.
* @param CDataProvider $dataProvider the data provider to iterate over
* @param integer $pageSize pageSize to use for iteration. This is the number of objects loaded into memory at the same time.
*/
public function __construct(CDataProvider $dataProvider, $pageSize=null)
{
$this->_dataProvider=$dataProvider;
$this->_totalItemCount=$dataProvider->getTotalItemCount();
if(($pagination=$this->_dataProvider->getPagination())===false)
$this->_dataProvider->setPagination($pagination=new CPagination());
if($pageSize!==null)
$pagination->setPageSize($pageSize);
}
/**
* Returns the data provider to iterate over
* @return CDataProvider the data provider to iterate over
*/
public function getDataProvider()
{
return $this->_dataProvider;
}
/**
* Gets the total number of items to iterate over
* @return integer the total number of items to iterate over
*/
public function getTotalItemCount()
{
return $this->_totalItemCount;
}
/**
* Loads a page of items
* @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()
{
return $this->_items[$this->_currentIndex];
}
/**
* 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()
{
$pageSize=$this->_dataProvider->getPagination()->getPageSize();
return $this->_currentPage*$pageSize+$this->_currentIndex;
}
/**
* Moves the pointer to the next item in the list.
* This method is required by the Iterator interface.
*/
public function next()
{
$pageSize=$this->_dataProvider->getPagination()->getPageSize();
$this->_currentIndex++;
if($this->_currentIndex >= $pageSize)
{
$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->_totalItemCount;
}
/**
* 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->_totalItemCount;
}
}