Subversion-Projekte lars-tiefland.prado

<?php

/**

 * TSqlMapPagedList class file.

 *

 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>

 * @link http://www.pradosoft.com/

 * @copyright Copyright © 2005-2008 PradoSoft

 * @license http://www.pradosoft.com/license/

 * @version $Id: TSqlMapPagedList.php 2541 2008-10-21 15:05:13Z qiang.xue $

 * @package System.Data.SqlMap

 */

Prado::using('System.Collections.TPagedList');

/**

 * TSqlMapPagedList implements a list with paging functionality that retrieves

 * data from a SqlMap statement.

 *

 * The maximum number of records fetched is 3 times the page size. It fetches

 * the current, the previous and the next page at a time. This allows the paged

 * list to determine if the page is a the begin, the middle or the end of the list.

 *

 * The paged list does not need to know about the total number of records.

 *

 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>

 * @version $Id: TSqlMapPagedList.php 2541 2008-10-21 15:05:13Z qiang.xue $

 * @package System.Data.SqlMap

 * @since 3.1

 */

class TSqlMapPagedList extends TPagedList

{

	private $_statement;

	private $_parameter;

	private $_prevPageList;

	private $_nextPageList;

	private $_delegate=null;

	/**

	 * Create a new SqlMap paged list.

	 * @param IMappedStatement SqlMap statement.

	 * @param mixed query parameters

	 * @param int page size

	 * @param mixed delegate for each data row retrieved.

	 * @param int number of page to fetch on initialization

	 */

	public function __construct(IMappedStatement $statement,$parameter, $pageSize, $delegate=null, $page=0)

	{

		parent::__construct();

		parent::setCustomPaging(true);

		$this->initialize($statement,$parameter, $pageSize, $page);

		$this->_delegate=$delegate;

	}

	/**

	 * Initialize the paged list.

	 * @param IMappedStatement SqlMap statement.

	 * @param mixed query parameters

	 * @param int page size.

	 * @param int number of page.

	 */

	protected function initialize($statement, $parameter, $pageSize, $page)

	{

		$this->_statement = $statement;

		$this->_parameter = $parameter;

		$this->setPageSize($pageSize);

		$this->attachEventHandler('OnFetchData', array($this, 'fetchDataFromStatement'));

		$this->gotoPage($page);

	}

	/**

	 * @throws TSqlMapException custom paging must be enabled.

	 */

	public function setCustomPaging($value)

	{

		throw new TSqlMapException('sqlmap_must_enable_custom_paging');

	}

	/**

	 * Fetch data by executing the SqlMap statement.

	 * @param TPageList current object.

	 * @param TPagedListFetchDataEventParameter fetch parameters

	 */

	protected function fetchDataFromStatement($sender, $param)

	{

		$limit = $this->getOffsetAndLimit($param);

		$connection = $this->_statement->getManager()->getDbConnection();

		$data = $this->_statement->executeQueryForList($connection,

						$this->_parameter, null, $limit[0], $limit[1], $this->_delegate);

		$this->populateData($param, $data);

	}

	/**

	 * Switches to the next page.

	 * @return integer|boolean the new page index, false if next page is not availabe.

	 */

	public function nextPage()

	{

		return $this->getIsNextPageAvailable() ? parent::nextPage() : false;

	}

	/**

	 * Switches to the previous page.

	 * @return integer|boolean the new page index, false if previous page is not availabe.

	 */

	public function previousPage()

	{

		return $this->getIsPreviousPageAvailable() ? parent::previousPage() : false;

	}

	/**

	 * Populate the list with the fetched data.

	 * @param TPagedListFetchDataEventParameter fetch parameters

	 * @param array fetched data.

	 */

	protected function populateData($param, $data)

	{

		$total = $data instanceof TList ? $data->getCount() : count($data);

		$pageSize = $this->getPageSize();

		if($total < 1)

		{

			$param->setData($data);

			$this->_prevPageList = null;

			$this->_nextPageList = null;

			return;

		}

		if($param->getNewPageIndex() < 1)

		{

			$this->_prevPageList = null;

			if($total <= $pageSize)

			{

				$param->setData($data);

				$this->_nextPageList = null;

			}

			else

			{

				$param->setData(array_slice($data, 0, $pageSize));

				$this->_nextPageList = array_slice($data, $pageSize-1,$total);

			}

		}

		else

		{

			if($total <= $pageSize)

			{

				$this->_prevPageList = array_slice($data, 0, $total);

				$param->setData(array());

				$this->_nextPageList = null;

			}

			else if($total <= $pageSize*2)

			{

				$this->_prevPageList = array_slice($data, 0, $pageSize);

				$param->setData(array_slice($data, $pageSize, $total));

				$this->_nextPageList = null;

			}

			else

			{

				$this->_prevPageList = array_slice($data, 0, $pageSize);

				$param->setData(array_slice($data, $pageSize, $pageSize));

				$this->_nextPageList = array_slice($data, $pageSize*2, $total-$pageSize*2);

			}

		}

	}

	/**

	 * Calculate the data fetch offsets and limits.

	 * @param TPagedListFetchDataEventParameter fetch parameters

	 * @return array 1st element is the offset, 2nd element is the limit.

	 */

	protected function getOffsetAndLimit($param)

	{

		$index = $param->getNewPageIndex();

		$pageSize = $this->getPageSize();

		return $index < 1 ? array($index, $pageSize*2) : array(($index-1)*$pageSize, $pageSize*3);

	}

	/**

	 * @return boolean true if the next page is available, false otherwise.

	 */

	public function getIsNextPageAvailable()

	{

		return !is_null($this->_nextPageList);

	}

	/**

	 * @return boolean true if the previous page is available, false otherwise.

	 */

	public function getIsPreviousPageAvailable()

	{

		return !is_null($this->_prevPageList);

	}

	/**

	 * @return boolean true if is the very last page, false otherwise.

	 */

	public function getIsLastPage()

	{

		return is_null($this->_nextPageList) || $this->_nextPageList->getCount() < 1;

	}

	/**

	 * @return boolean true if is not first nor last page, false otherwise.

	 */

	public function getIsMiddlePage()

	{

		return !($this->getIsFirstPage() || $this->getIsLastPage());

	}

}