Source for file NumberVersionConstraint.class.php

<?php
 
require_once HARMONI."dataManager/versionConstraints/VersionConstraint.interface.php";
 
/**
 * Removes versions based on the number for a certain value stored in the database. The maximum number
 * allowed is passed to the constructor, and any extra values will be deleted based on age.
 *
 * @package harmoni.datamanager.versionconstraint
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: NumberVersionConstraint.class.php,v 1.5 2007/09/04 20:25:33 adamfranco Exp $
 */
class NumberVersionConstraint extends VersionConstraint {
    
    var $_num;
    
    function NumberVersionConstraint( $num ) {
        $this->_num = $num;
    }
    
    function checkRecordFieldValue($value) {
        $numVers = $value->numVersions();
        
        if ($numVers <= $this->_num) return; // it's all good. nothing to do
        
        $timestamps = array();
        $versions = array();
        
        foreach ($value->getVersionIDs() as $verID) {
            $ver =$value->getVersion($verID);
            $date =$ver->getDate();
            $timestamp = $date->toTimestamp();
            
            $timestamps[] = $timestamp;
            $versions[$timestamp] =$ver;
        }
        
        // sort the versions from oldest to newest
        asort($timestamps);
        
        for ($i=0; $i<count($timestamps); $i++) {
            $tstamp = $timestamps[$i];
            
            if ($versions[$tstamp]->isActive()) continue;
            
            $versions[$tstamp]->prune();
            $numVers--;
            
            if ($numVers <= $this->_num) return;
        }
    }
    
    function checkTags($record) {
        // do nothing
        return;
    }
    
    function checkRecord($record) {
        // do nothing
        return true;
    }
    
}