Source for file PersistentOrderedSet.class.php

<?php
 
require_once(dirname(__FILE__)."/OrderedSet.class.php");
 
/**
 * The Set provides an implementation of the set interface that stores the
 * sets of ids in a database. Note: Nothing should be implied in the order that
 * the ids are returned.
 * Sets provide for the easy storage of groups of ids.
 *
 * @package  harmoni.sets
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: PersistentOrderedSet.class.php,v 1.5 2007/09/13 16:04:21 adamfranco Exp $
 * @author Adam Franco
 */
 
class PersistentOrderedSet 
    extends OrderedSet {
    
    /**
     * @var int $_dbIndex The dbIndex where this set is stored.
     * @access private
     */
    var $_dbIndex;
    
    /**
     * Constructor.
     * @param object Id $setId The Id of this set.
      * @param integer $dbIndex The index of the database connection which has
     *          tables in which to store the set.
     */
    function PersistentOrderedSet ( $setId, $dbIndex ) {
        parent::OrderedSet($setId);
        
        ArgumentValidator::validate($dbIndex, IntegerValidatorRule::getRule(), true);
        
        // Create our internal array
        $this->_dbIndex = $dbIndex;
        
        // populate our array with any previously stored items.
        $query = new SelectQuery;
        $query->addColumn("item_order", "item_order");
        $query->addColumn("item_id", "item_id");
        $query->addTable("sets");
        $query->addWhere("id = '".addslashes($this->_setId->getIdString())."'");
        $query->addOrderBy("item_order");
        
        $dbHandler = Services::getService("DatabaseManager");
        $result =$dbHandler->query($query, $this->_dbIndex);
        
        $i = 0;
        $oldItems = array();
        while ($result->hasMoreRows()) {
            // Add the items to our array
            $this->_items[$i] = $result->field("item_id");
            
            // Store an array of the order-key/value relationships to reference
            // when updating any inconsistancies in order numbering.
            $oldItems[$result->field("item_order")] = $result->field("item_id");
                                    
            $i++;
            $result->advanceRow();
        }
        $result->free();
 
        // Make sure that we have our set is filled from 0 to count()
        reset($oldItems);
        $this->_updateOrders($oldItems);
    }
    
    /**
     * Add a new Id to the set.
     * @param object Id $id The Id to add.
     * @access public
     * @return void 
     */
    function addItem ( $id ) {
        parent::addItem($id);
        
        $position = $this->getPosition($id);
        
        // Add the item to the database
        $query = new InsertQuery;
        $query->setTable("sets");
        $columns = array("id", "item_id", "item_order");
        $values = array("'".addslashes($this->_setId->getIdString())."'", "'".addslashes($id->getIdString())."'", "'".$position."'");
        $query->setColumns($columns);
        $query->setValues($values);
        
        $dbHandler = Services::getService("DatabaseManager");
        $dbHandler->query($query, $this->_dbIndex);
    }
    
    /**
     * Remove an Id from the set.
     * @param object Id $id The Id to remove.
     * @access public
     * @return void 
     */
    function removeItem ( $id ) {
        // Store the old order 
        $oldOrder = $this->_items;
        
        // remove the Item
        parent::removeItem($id);
        
        // update the database with the new order keys.
        $this->_updateOrders($oldOrder);
        
        // Remove the item from the database
        $query = new DeleteQuery;
        $query->setTable("sets");
        $query->addWhere("id='".addslashes($this->_setId->getIdString())."'");
        $query->addWhere("item_id='".addslashes($id->getIdString())."'");
        
        $dbHandler = Services::getService("DatabaseManager");
        $dbHandler->query($query, $this->_dbIndex);
    }
    
    /**
     * Remove all Items from the set.
     * @access public
     * @return void 
     */
    function removeAllItems () {
        parent::removeAllItems();
        
        // Remove the item from the database
        $query = new DeleteQuery;
        $query->setTable("sets");
        $query->addWhere("id='".addslashes(
            $this->_setId->getIdString())."'");
                
        $dbHandler = Services::getService("DatabaseManager");
        $dbHandler->query($query, $this->_dbIndex);
    }
    
    /**
     * Move the specified id to the specified position in the set.
     * @param object Id $id The Id of the item to move.
     * @param integer $position The new position of the specified id.
     * @access public
     * @return void 
     */
    function moveToPosition ( $id, $position ) {
        // Store the old order 
        $oldOrder = $this->_items;
        
        // remove the Item
        parent::moveToPosition($id, $position);
        
        // update the database with the new order keys.
        $this->_updateOrders($oldOrder);
    }
    
    /**
     * Move the specified id toward the begining of the set.
     * @param object Id $id The Id of the item to move.
     * @access public
     * @return void 
     */
    function moveUp ( $id ) {
        // Store the old order 
        $oldOrder = $this->_items;
        
        // move the Item
        parent::moveUp($id);
        
        // update the database with the new order keys.
        $this->_updateOrders($oldOrder);
    }
    
    /**
     * Move the specified id toward the end of the set.
     * @param object Id $id The Id of the item to move.
     * @access public
     * @return void 
     */
    function moveDown ( $id ) {
        // Store the old order 
        $oldOrder = $this->_items;
        
        // move the Item
        parent::moveDown($id);
        
        // update the database with the new order keys.
        $this->_updateOrders($oldOrder);
    }
    
    /**
     * Update the orders of the ids in the database.
     * @param array $oldOrders The previous orders to compare so that only
     *         updates will be done to changed orders.
     * @access private
     * @return void 
     */
    function _updateOrders ( $oldOrders ) {
        $dbHandler = Services::getService("DatabaseManager");
 
        foreach ($this->_items as $key => $val) {
            // If the old key-value pairs don't match the current ones, 
            // update that row
            if ($oldOrders[$key] != $val) {
                $query = new UpdateQuery;
                $query->setTable("sets");
                $columns = array("item_order");
                $query->setColumns($columns);
                $values = array($key);
                $query->setValues($values);
                $query->addWhere("id = '".addslashes($this->_setId->getIdString())."'");
                $query->addWhere("item_id = '".addslashes($val)."'");
                
                $dbHandler->query($query);
            }
        }
    }
}