<?php

/*
 *  $Id: PagedQuery.php,v 1.5 2004/06/20 17:10:07 micha Exp $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information please see
 * <http://creole.phpdb.org>.
 */

require_once 'jargon/Query.php';

/**
 * Class for representing a SQL query for retrieving paged results from a database.
 * 
 * Note that this class is for retrieving results and not performing updates.
 * 
 * 
 * @author    Hans Lellelid <hide@address.com>
 * @version   $Revision: 1.5 $
 * @package   jargon 
 */
class PagedQuery extends Query {
    
    /** @var int Current page number (1-based). */
    private $page;
    
    /**
     * Create a new Query.
     * @param Connection $conn
     * @param string $sql
     */
    public function __construct(Connection $conn, $sql = null, $page = 1, $rowsPerPage = 25)
    {
        parent::__construct($conn, $sql);
        $this->setRowsPerPage($rowsPerPage);
        $this->setPage($page);
    }
    
    /**
     * Set the current page number (First page is 1).
     * @param int $page
     * @return void
     */
    public function setPage($page)
    {
        $this->page = $page;
        // (re-)calculate start rec
        $this->calculateStart();
    }
    
    /**
     * Get current page.
     * @return int
     */
    public function getPage()
    {
        return $this->page;
    }
    
    /**
     * Set the number of rows per page.
     * @param int $r
     */
    public function setRowsPerPage($r)
    {
        $this->max = $r;
        // (re-)calculate start rec
        $this->calculateStart();
    }
    
    /**
     * Get number of rows per page.
     * @return int
     */
    public function getRowsPerPage()
    {
        return $this->max;
    }
    
    /**
     * Calculate startrow / max rows based on current page and rows-per-page.
     * @return void
     */
    private function calculateStart()
    {
        $this->start = ( ($this->page - 1) * $this->max );
    }
    
    /**
     * Gets the total number (un-LIMITed) of records.
     * 
     * This method will perform a query that executes un-LIMITed query.  This
     * method is not performance-conscious, so don't call this repeatedly for
     * the same query.
     * 
     * @return int Total number of records - disregarding page, maxrows, etc.
     * @throws SQLException
     */
    public function getTotalRecordCount()
    {
        $rs = $this->conn->createStatement()->executeQuery($this->sql);
        return $rs->getRecordCount();
    }
        
}