classes/class.ilObject.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2001 ILIAS open source, University of Cologne            |
        |                                                                             |
        | This program is free software; you can redistribute it and/or               |
        | modify it under the terms of the GNU General Public License                 |
        | as published by the Free Software Foundation; either version 2              |
        | of the License, or (at your option) any later version.                      |
        |                                                                             |
        | This program is distributed in the hope that it will be useful,             |
        | but WITHOUT ANY WARRANTY; without even the implied warranty of              |
        | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               |
        | GNU General Public License for more details.                                |
        |                                                                             |
        | You should have received a copy of the GNU General Public License           |
        | along with this program; if not, write to the Free Software                 |
        | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
        +-----------------------------------------------------------------------------+
*/


class ilObject
{
        var $ilias;

        var $lng;

        var $id;        // true object_id!!!!
        var $ref_id;// reference_id
        var $type;
        var $title;
        var $desc;
        var $long_desc;
        var $owner;
        var $create_date;
        var $last_update;
        var $import_id;
        var $register = false;          // registering required for object? set to true to implement a subscription interface

        var $referenced;

        var $objectList;

        var $max_title;

        var $max_desc;

        var $add_dots;

        var $obj_data_record;

        function ilObject($a_id = 0, $a_reference = true)
        {
                global $ilias, $lng, $ilBench;

                $ilBench->start("Core", "ilObject_Constructor");

                if (DEBUG)
                {
                        echo "<br/><font color=\"red\">type(".$this->type.") id(".$a_id.") referenced(".$a_reference.")</font>";
                }

                $this->ilias =& $ilias;
                $this->lng =& $lng;

                $this->max_title = MAXLENGTH_OBJ_TITLE;
                $this->max_desc = MAXLENGTH_OBJ_DESC;
                $this->add_dots = true;

                $this->referenced = $a_reference;
                $this->call_by_reference = $a_reference;

                if ($a_id == 0)
                {
                        $this->referenced = false;              // newly created objects are never referenced
                }                                                                       // they will get referenced if createReference() is called

                if ($this->referenced)
                {
                        $this->ref_id = $a_id;
                }
                else
                {
                        $this->id = $a_id;
                }
                // read object data
                if ($a_id != 0)
                {
                        $this->read();
                }

                $ilBench->stop("Core", "ilObject_Constructor");
        }

        function withReferences()
        {
                // both vars could differ. this method should always return true if one of them is true without changing their status
                return ($this->call_by_reference) ? true : $this->referenced;
        }


        function read($a_force_db = false)
        {
                global $objDefinition, $ilBench, $ilDB;

                $ilBench->start("Core", "ilObject_read");

                if (isset($this->obj_data_record) && !$a_force_db)
                {
                        $obj = $this->obj_data_record;
                }
                else if ($this->referenced)
                {
                        // check reference id
                        if (!isset($this->ref_id))
                        {
                                $message = "ilObject::read(): No ref_id given! (".$this->type.")";
                                $this->ilias->raiseError($message,$this->ilias->error_obj->WARNING);
                        }

                        // read object data
                        $ilBench->start("Core", "ilObject_read_readData");
                        /* old query (very slow)
                        $q = "SELECT * FROM object_data ".
                                 "LEFT JOIN object_reference ON object_data.obj_id=object_reference.obj_id ".
                                 "WHERE object_reference.ref_id='".$this->ref_id."'"; */

                        $q = "SELECT * FROM object_data, object_reference WHERE object_data.obj_id=object_reference.obj_id ".
                                 "AND object_reference.ref_id= ".$ilDB->quote($this->ref_id);
                        $object_set = $this->ilias->db->query($q);
                        $ilBench->stop("Core", "ilObject_read_readData");

                        // check number of records
                        if ($object_set->numRows() == 0)
                        {
                                $message = "ilObject::read(): Object with ref_id ".$this->ref_id." not found! (".$this->type.")";
                                $this->ilias->raiseError($message,$this->ilias->error_obj->WARNING);
                        }

                        $obj = $object_set->fetchRow(DB_FETCHMODE_ASSOC);
                }
                else
                {
                        // check object id
                        if (!isset($this->id))
                        {
                                $message = "ilObject::read(): No obj_id given! (".$this->type.")";
                                $this->ilias->raiseError($message,$this->ilias->error_obj->WARNING);
                        }

                        // read object data
                        $q = "SELECT * FROM object_data ".
                                 "WHERE obj_id = ".$ilDB->quote($this->id);
                        $object_set = $this->ilias->db->query($q);

                        // check number of records
                        if ($object_set->numRows() == 0)
                        {
                                $message = "ilObject::read(): Object with obj_id: ".$this->id." (".$this->type.") not found!";
                                $this->ilias->raiseError($message,$this->ilias->error_obj->WARNING);
                        }

                        $obj = $object_set->fetchRow(DB_FETCHMODE_ASSOC);
                }

                $this->id = $obj["obj_id"];
                $this->type = $obj["type"];
                $this->title = $obj["title"];
                $this->desc = $obj["description"];
                $this->owner = $obj["owner"];
                $this->create_date = $obj["create_date"];
                $this->last_update = $obj["last_update"];
                $this->import_id = $obj["import_id"];

                if($objDefinition->isRBACObject($this->getType()))
                {
                        // Read long description
                        $query = "SELECT * FROM object_description WHERE obj_id = ".$ilDB->quote($this->id);
                        $res = $this->ilias->db->query($query);
                        while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                        {
                                $this->setDescription($row->description);
                        }
                }

                // multilingual support systemobjects (sys) & categories (db)
                $ilBench->start("Core", "ilObject_Constructor_getTranslation");
                $translation_type = $objDefinition->getTranslationType($this->type);

                if ($translation_type == "sys")
                {
                        $this->title = $this->lng->txt("obj_".$this->type);
                        $this->desc = $this->lng->txt("obj_".$this->type."_desc");
                }
                elseif ($translation_type == "db")
                {
                        $q = "SELECT title,description FROM object_translation ".
                                 "WHERE obj_id = ".$ilDB->quote($this->id)." ".
                                 "AND lang_code = ".$ilDB->quote($this->ilias->account->getCurrentLanguage())." ".
                                 "AND NOT lang_default = 1";
                        $r = $this->ilias->db->query($q);
                        $row = $r->fetchRow(DB_FETCHMODE_OBJECT);

                        if ($row)
                        {
                                $this->title = $row->title;
                                $this->setDescription($row->description);
                                #$this->desc = $row->description;
                        }
                }

                $ilBench->stop("Core", "ilObject_Constructor_getTranslation");

                $ilBench->stop("Core", "ilObject_read");
        }

        function getId()
        {
                return $this->id;
        }

        function setId($a_id)
        {
                $this->id = $a_id;
        }

        function setRefId($a_id)
        {
                $this->ref_id = $a_id;
                $this->referenced = true;
        }

        function getRefId()
        {
                return $this->ref_id;
        }

        function getType()
        {
                return $this->type;
        }

        function setType($a_type)
        {
                $this->type = $a_type;
        }

        function getTitle()
        {
                return $this->title;
        }

        function setTitle($a_title)
        {
                if ($a_title == "")
                {
                        $a_title = "NO TITLE";
                }

                $this->title = ilUtil::shortenText($a_title, $this->max_title, $this->add_dots);
        }

        function getDescription()
        {
                return $this->desc;
        }

        function setDescription($a_desc)
        {
                // Shortened form is storted in object_data. Long form is stored in object_description
                $this->desc = ilUtil::shortenText($a_desc, $this->max_desc, $this->add_dots);

                $this->long_desc = $a_desc;

                return true;
        }

        function getLongDescription()
        {
                return strlen($this->long_desc) ? $this->long_desc : $this->desc;
        }

        function getImportId()
        {
                return $this->import_id;
        }

        function setImportId($a_import_id)
        {
                $this->import_id = $a_import_id;
        }

        function _lookupObjIdByImportId($a_import_id)
        {
                global $ilDB;

                $query = "SELECT * FROM object_data ".
                        "WHERE import_id = '".$a_import_id."' ".
                        "ORDER BY create_date DESC";
                $res = $ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        return $row->obj_id;
                }
                return 0;
        }

        function getOwner()
        {
                return $this->owner;
        }

        /*
        * get full name of object owner
        *
        * @access       public
        * @return       string  owner name or unknown
        */
        function getOwnerName()
        {
                return ilObject::_lookupOwnerName($this->getOwner());
        }

        function _lookupOwnerName($a_owner_id)
        {
                global $lng;

                if ($a_owner_id != -1)
                {
                        if (ilObject::_exists($a_owner_id))
                        {
                                $owner = new ilObjUser($a_owner_id);
                        }
                }

                if (is_object($owner))
                {
                        $own_name = $owner->getFullname();
                }
                else
                {
                        $own_name = $lng->txt("unknown");
                }

                return $own_name;
        }

        function setOwner($a_owner)
        {
                $this->owner = $a_owner;
        }



        function getCreateDate()
        {
                return $this->create_date;
        }

        function getLastUpdateDate()
        {
                return $this->last_update;
        }

        function setObjDataRecord($a_record)
        {
                $this->obj_data_record = $a_record;
        }

        function create()
        {
                global $ilDB, $log,$ilUser,$objDefinition;

                if (!isset($this->type))
                {
                        $message = get_class($this)."::create(): No object type given!";
                        $this->ilias->raiseError($message,$this->ilias->error_obj->WARNING);
                }

                // write log entry
                $log->write("ilObject::create(), start");

                $this->title = ilUtil::shortenText($this->getTitle(), $this->max_title, $this->add_dots);
                $this->desc = ilUtil::shortenText($this->getDescription(), $this->max_desc, $this->add_dots);
                
                // determine owner
                if ($this->getOwner() > 0)
                {
                        $owner = $this->getOwner();
                }
                else
                {
                        $owner = $ilUser->getId();
                }

                $q = "INSERT INTO object_data ".
                         "(type,title,description,owner,create_date,last_update,import_id) ".
                         "VALUES ".
                         "('".$this->type."',".$ilDB->quote($this->getTitle()).",'".ilUtil::prepareDBString($this->getDescription())."',".
                         "'".$owner."',now(),now(),'".
                        $this->getImportId()."')";

                $ilDB->query($q);

                $this->id = $ilDB->getLastInsertId();


                
                // Save long form of description if is rbac object
                if($objDefinition->isRBACObject($this->getType()))
                {
                        $query = "INSERT INTO object_description SET ".
                                "obj_id = '".$this->id."', ".
                                "description = '".ilUtil::prepareDBString($this->getLongDescription())."'";
                        
                        $ilDB->query($query);
                }
                

                // the line ($this->read();) messes up meta data handling: meta data,
                // that is not saved at this time, gets lost, so we query for the dates alone
                //$this->read();
                $q = "SELECT last_update, create_date FROM object_data".
                         " WHERE obj_id = '".$this->id."'";
                $obj_set = $this->ilias->db->query($q);
                $obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC);
                $this->last_update = $obj_rec["last_update"];
                $this->create_date = $obj_rec["create_date"];

                // set owner for new objects
                $this->setOwner($owner);

                // write log entry
                $log->write("ilObject::create(), finished, obj_id: ".$this->id.", type: ".
                        $this->type.", title: ".$this->getTitle());

                return $this->id;
        }

        function update()
        {
                global $objDefinition, $ilDB;

                $q = "UPDATE object_data ".
                        "SET ".
                        "title = '".ilUtil::prepareDBString($this->getTitle())."',".
                        "description = '".ilUtil::prepareDBString($this->getDescription())."', ".
                        "import_id = '".$this->getImportId()."', ".
                        "last_update = now() ".
                        "WHERE obj_id = '".$this->getId()."'";
                $this->ilias->db->query($q);

                // the line ($this->read();) messes up meta data handling: meta data,
                // that is not saved at this time, gets lost, so we query for the dates alone
                //$this->read();
                $q = "SELECT last_update FROM object_data".
                         " WHERE obj_id = ".$ilDB->quote($this->getId());
                $obj_set = $this->ilias->db->query($q);
                $obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC);
                $this->last_update = $obj_rec["last_update"];

                if($objDefinition->isRBACObject($this->getType()))
                {
                        // Update long description
                        $res = $this->ilias->db->query("SELECT * FROM object_description WHERE obj_id = '".$this->getId()."'");
                        if($res->numRows())
                        {
                                $query = "UPDATE object_description SET description = '".
                                        ilUtil::prepareDBString($this->getLongDescription())."' ".
                                        "WHERE obj_id = '".$this->getId()."'";
                        }
                        else
                        {
                                $query = "INSERT INTO object_description SET obj_id = '".$this->getId()."', ".
                                        "description = '".ilUtil::prepareDBString($this->getLongDescription())."'";
                        }
                        $this->ilias->db->query($query);
                }               

                return true;
        }

        function MDUpdateListener($a_element)
        {
                include_once 'Services/MetaData/classes/class.ilMD.php';

                switch($a_element)
                {
                        case 'General':

                                // Update Title and description
                                $md = new ilMD($this->getId(),0, $this->getType());
                                if(!is_object($md_gen = $md->getGeneral()))
                                {
                                        return false;
                                }

                                ilObject::_writeTitle($this->getId(),$md_gen->getTitle());
                                $this->setTitle($md_gen->getTitle());

                                foreach($md_gen->getDescriptionIds() as $id)
                                {
                                        $md_des = $md_gen->getDescription($id);
                                        ilObject::_writeDescription($this->getId(),$md_des->getDescription());
                                        $this->setDescription($md_des->getDescription());
                                        break;
                                }

                                break;

                        default:
                }
                return true;
        }

        function createMetaData()
        {
                include_once 'Services/MetaData/classes/class.ilMDCreator.php';

                global $ilUser;

                $md_creator = new ilMDCreator($this->getId(),0,$this->getType());
                $md_creator->setTitle($this->getTitle());
                $md_creator->setTitleLanguage($ilUser->getPref('language'));
                $md_creator->setDescription($this->getLongDescription());
                $md_creator->setDescriptionLanguage($ilUser->getPref('language'));
                $md_creator->setKeywordLanguage($ilUser->getPref('language'));
                $md_creator->setLanguage($ilUser->getPref('language'));
                $md_creator->create();

                return true;
        }

        function updateMetaData()
        {
                include_once("Services/MetaData/classes/class.ilMD.php");
                include_once("Services/MetaData/classes/class.ilMDGeneral.php");
                include_once("Services/MetaData/classes/class.ilMDDescription.php");

                $md =& new ilMD($this->getId(), 0, $this->getType());
                $md_gen =& $md->getGeneral();
                $md_gen->setTitle($this->getTitle());

                // sets first description (maybe not appropriate)
                $md_des_ids =& $md_gen->getDescriptionIds();
                if (count($md_des_ids) > 0)
                {
                        $md_des =& $md_gen->getDescription($md_des_ids[0]);
                        $md_des->setDescription($this->getLongDescription());
                        $md_des->update();
                }
                $md_gen->update();

        }

        function deleteMetaData()
        {
                // Delete meta data
                include_once('Services/MetaData/classes/class.ilMD.php');
                $md = new ilMD($this->getId(), 0, $this->getType());
                $md->deleteAll();
        }

    function updateOwner()
    {
        $q = "UPDATE object_data ".
            "SET ".
            "owner = '".$this->getOwner()."', ".
            "last_update = now() ".
            "WHERE obj_id = '".$this->getId()."'";
        $this->ilias->db->query($q);

        $q = "SELECT last_update FROM object_data".
             " WHERE obj_id = '".$this->getId()."'";
        $obj_set = $this->ilias->db->query($q);
        $obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC);
        $this->last_update = $obj_rec["last_update"];

        return true;
    }

        function _getIdForImportId($a_import_id)
        {
                global $ilDB;
                
                $q = "SELECT * FROM object_data WHERE import_id = ".$ilDB->quote($a_import_id).
                        " ORDER BY create_date DESC LIMIT 1";
                $obj_set = $ilDB->query($q);

                if ($obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        return $obj_rec["obj_id"];
                }
                else
                {
                        return 0;
                }
        }

        function _getAllReferences($a_id)
        {
                global $ilDB;

                $q = "SELECT * FROM object_reference WHERE obj_id = ".
                        $ilDB->quote($a_id);
                $obj_set = $ilDB->query($q);
                $ref = array();

                while ($obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $ref[$obj_rec["ref_id"]] = $obj_rec["ref_id"];
                }

                return $ref;
        }

        function _lookupTitle($a_id)
        {
                global $ilObjDataCache;

                return $ilObjDataCache->lookupTitle($a_id);
        }

        function _lookupDescription($a_id)
        {
                global $ilObjDataCache;

                return $ilObjDataCache->lookupDescription($a_id);
        }

        function _lookupLastUpdate($a_id, $a_as_string = false)
        {
                global $ilObjDataCache;
                
                if ($a_as_string)
                {
                        include_once("classes/class.ilFormat.php");
                        return ilFormat::formatDate($ilObjDataCache->lookupLastUpdate($a_id), "datetime", true);
                }
                else
                {
                        return $ilObjDataCache->lookupLastUpdate($a_id);
                }
        }

        function _lookupObjId($a_id)
        {
                global $ilObjDataCache;

                return (int) $ilObjDataCache->lookupObjId($a_id);
        }
        
        function _setDeletedDate($a_ref_id)
        {
                global $ilDB;
                
                $q = "UPDATE object_reference SET deleted=now() ".
                        "WHERE ref_id = ".$ilDB->quote($a_ref_id);
                $ilDB->query($q);
        }

        function _resetDeletedDate($a_ref_id)
        {
                global $ilDB;
                
                $q = "UPDATE object_reference SET deleted= ".$ilDB->quote("0000-00-00 00:00:00").
                        " WHERE ref_id = ".$ilDB->quote($a_ref_id);
                $ilDB->query($q);
        }

        function _writeTitle($a_obj_id, $a_title)
        {
                global $ilDB;

                $q = "UPDATE object_data ".
                        "SET ".
                        "title = ".$ilDB->quote($a_title).",".
                        "last_update = now() ".
                        "WHERE obj_id = ".$ilDB->quote($a_obj_id);

                $ilDB->query($q);
        }

        function _writeDescription($a_obj_id, $a_desc)
        {
                global $ilDB,$objDefinition;


                $desc = ilUtil::shortenText($a_desc,MAXLENGTH_OBJ_DESC,true);

                $q = "UPDATE object_data ".
                        "SET ".
                        "description = ".$ilDB->quote($desc).",".
                        "last_update = now() ".
                        "WHERE obj_id = ".$ilDB->quote($a_obj_id);

                $ilDB->query($q);

                if($objDefinition->isRBACObject($this->getType()))
                {
                        // Update long description
                        $res = $ilDB->query("SELECT * FROM object_description WHERE obj_id = '".$a_obj_id."'");
                        if($res->numRows())
                        {
                                $query = "UPDATE object_description SET description = '".
                                        ilUtil::prepareDBString($a_desc)."' ".
                                        "WHERE obj_id = '".$this->getId()."'";
                        }
                        else
                        {
                                $query = "INSERT INTO object_description SET obj_id = '".$this->getId()."', ".
                                        "description = '".ilUtil::prepareDBString($a_desc)."'";
                        }
                        $ilDB->query($query);
                }
        }

        function _writeImportId($a_obj_id, $a_import_id)
        {
                global $ilDB;

                $q = "UPDATE object_data ".
                        "SET ".
                        "import_id = ".$ilDB->quote($a_import_id).",".
                        "last_update = now() ".
                        "WHERE obj_id = ".$ilDB->quote($a_obj_id);

                $ilDB->query($q);
        }

        function _lookupType($a_id,$a_reference = false)
        {
                global $ilObjDataCache;

                if($a_reference)
                {
                        return $ilObjDataCache->lookupType($ilObjDataCache->lookupObjId($a_id));
                }
                return $ilObjDataCache->lookupType($a_id);

                global $ilDB;

                if ($a_reference === true)
                {
                        $q = "SELECT type FROM object_reference as obr, object_data as obd ".
                                "WHERE obr.ref_id = ".$ilDB->quote($a_id)." ".
                                "AND obr.obj_id = obd.obj_id ";
                        
                        #$q = "SELECT type FROM object_data as obj ".
                        #        "LEFT JOIN object_reference as ref ON ref.obj_id=obj.obj_id ".
                        #        "WHERE ref.ref_id = '".$a_id."'";
                }
                else
                {
                        $q = "SELECT type FROM object_data WHERE obj_id = ".$ilDB->quote($a_id);
                }

                $obj_set = $ilDB->query($q);
                $obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC);

                return $obj_rec["type"];
        }

        function _isInTrash($a_ref_id)
        {
                global $tree;

                return $tree->isSaved($a_ref_id);
        }

        function _hasUntrashedReference($a_obj_id)
        {
                $ref_ids  = ilObject::_getAllReferences($a_obj_id);
                foreach($ref_ids as $ref_id)
                {
                        if(!ilObject::_isInTrash($ref_id))
                        {
                                return true;
                        }
                }

                return false;
        }

        function _lookupObjectId($a_ref_id)
        {
                global $ilObjDataCache;

                return (int) $ilObjDataCache->lookupObjId($a_ref_id);
        }

        function _getObjectsDataForType($a_type, $a_omit_trash = false)
        {
                global $ilDB;

                $q = "SELECT * FROM object_data WHERE type = ".$ilDB->quote($a_type);
                $obj_set = $ilDB->query($q);

                $objects = array();
                while ($obj_rec = $obj_set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        if ((!$a_omit_trash) || ilObject::_hasUntrashedReference($obj_rec["obj_id"]))
                        {
                                $objects[$obj_rec["title"].".".$obj_rec["obj_id"]] = array("id" => $obj_rec["obj_id"],
                                        "type" => $obj_rec["type"], "title" => $obj_rec["title"],
                                        "description" => $obj_rec["description"]);
                        }
                }
                ksort($objects);
                return $objects;
        }

        function putInTree($a_parent_ref)
        {
                global $tree, $log;

                $tree->insertNode($this->getRefId(), $a_parent_ref);
                
                // write log entry
                $log->write("ilObject::putInTree(), parent_ref: $a_parent_ref, ref_id: ".
                        $this->getRefId().", obj_id: ".$this->getId().", type: ".
                        $this->getType().", title: ".$this->getTitle());

        }

        function setPermissions($a_parent_ref)
        {
                global $rbacadmin, $rbacreview;

                $parentRoles = $rbacreview->getParentRoleIds($a_parent_ref);

                foreach ($parentRoles as $parRol)
                {
                        $ops = $rbacreview->getOperationsOfRole($parRol["obj_id"], $this->getType(), $parRol["parent"]);
                        $rbacadmin->grantPermission($parRol["obj_id"], $ops, $this->getRefId());
                }
        }

        function createReference()
        {
                global $ilDB;

                if (!isset($this->id))
                {
                        $message = "ilObject::createNewReference(): No obj_id given!";
                        $this->raiseError($message,$this->ilias->error_obj->WARNING);
                }

                $q = "INSERT INTO object_reference ".
                         "(obj_id) VALUES ('".$this->id."')";
                $this->ilias->db->query($q);

                $this->ref_id = $ilDB->getLastInsertId();
                $this->referenced = true;

                return $this->ref_id;
        }


        function countReferences()
        {
                if (!isset($this->id))
                {
                        $message = "ilObject::countReferences(): No obj_id given!";
                        $this->ilias->raiseError($message,$this->ilias->error_obj->WARNING);
                }

                $q = "SELECT COUNT(ref_id) AS num FROM object_reference ".
                        "WHERE obj_id = '".$this->id."'";
                $row = $this->ilias->db->getRow($q);

                return $row->num;
        }


        function ilClone($a_parent_ref)
        {
                global $log;
                
                $new_obj = new ilObject();
                $new_obj->setTitle($this->getTitle());
                $new_obj->setType($this->getType());
                $new_obj->setDescription($this->getDescription());
                $new_obj->create();
                $new_ref_id = $new_obj->createReference();
                $new_obj->putInTree($a_parent_ref);
                $new_obj->setPermissions($a_parent_ref);

                unset($new_obj);
                
                // write log entry
                $log->write("ilObject::ilClone(), ref_id: ".$this->getRefId().",obj_id: ".$this->getId().", type: ".
                        $this->getType().", title: ".$this->getTitle().
                        ", new ref_id: ".$new_obj->getRefId().", new obj_id:".$new_obj->getId());
        
                // ... and finally always return new reference ID!!
                return $new_ref_id;
        }


        function delete()
        {
                global $rbacadmin, $log;

                $remove = false;

                // delete object_data entry
                if ((!$this->referenced) || ($this->countReferences() == 1))
                {
                        // delete entry in object_data
                        $q = "DELETE FROM object_data ".
                                "WHERE obj_id = '".$this->getId()."'";
                        $this->ilias->db->query($q);

                        // delete long description
                        $query = "DELETE FROM object_description WHERE obj_id = '".$this->getId()."'";
                        $this->ilias->db->query($query);

                        // write log entry
                        $log->write("ilObject::delete(), deleted object, obj_id: ".$this->getId().", type: ".
                                $this->getType().", title: ".$this->getTitle());
                        
                        $remove = true;
                }
                else
                {
                        // write log entry
                        $log->write("ilObject::delete(), object not deleted, number of references: ".
                                $this->countReferences().", obj_id: ".$this->getId().", type: ".
                                $this->getType().", title: ".$this->getTitle());
                }

                // delete object_reference entry
                if ($this->referenced)
                {
                        // delete entry in object_reference
                        $q = "DELETE FROM object_reference ".
                                "WHERE ref_id = '".$this->getRefId()."'";
                        $this->ilias->db->query($q);

                        // write log entry
                        $log->write("ilObject::delete(), reference deleted, ref_id: ".$this->getRefId().
                                ", obj_id: ".$this->getId().", type: ".
                                $this->getType().", title: ".$this->getTitle());

                        // DELETE PERMISSION ENTRIES IN RBAC_PA
                        // DONE: method overwritten in ilObjRole & ilObjUser.
                        // this call only applies for objects in rbac (not usr,role,rolt)
                        // TODO: Do this for role templates too
                        $rbacadmin->revokePermission($this->getRefId(),0,false);

                        // Remove desktop items
                        ilUtil::removeItemFromDesktops($this->getRefId());
                }

                // remove conditions
                if ($this->referenced)
                {
                        $ch =& new ilConditionHandler();
                        $ch->delete($this->getRefId());
                        unset($ch);
                }

                

                return $remove;
        }

        function initDefaultRoles()
        {
                return array();
        }
        
        function createRoleFolder()
        {
                global $rbacreview;
                
                // does a role folder already exists?
                // (this check is only 'to be sure' that no second role folder is created under one object.
                // the if-construct should never return true)
                if ($rolf_data = $rbacreview->getRoleFolderofObject($this->getRefId()))
                {
                        $rfoldObj = $this->ilias->obj_factory->getInstanceByRefId($rolf_data["ref_id"]);
                }
                else
                {
                        include_once ("classes/class.ilObjRoleFolder.php");
                        $rfoldObj = new ilObjRoleFolder();
                        $rfoldObj->setTitle($this->getId());
                        $rfoldObj->setDescription(" (ref_id ".$this->getRefId().")");
                        $rfoldObj->create();
                        $rfoldObj->createReference();
                        $rfoldObj->putInTree($this->getRefId());
                        $rfoldObj->setPermissions($this->getRefId());
                }
                
                return $rfoldObj;
        }

        function _exists($a_id, $a_reference = false)
        {
                global $ilias;
                
                if ($a_reference)
                {
                        $q = "SELECT * FROM object_data ".
                                 "LEFT JOIN object_reference ON object_reference.obj_id=object_data.obj_id ".
                                 "WHERE object_reference.ref_id='".$a_id."'";
                }
                else
                {
                        $q = "SELECT * FROM object_data WHERE obj_id='".$a_id."'";
                }
                
                $r = $ilias->db->query($q);

                return $r->numRows() ? true : false;
        }

        function notify($a_event,$a_ref_id,$a_parent_non_rbac_id,$a_node_id,$a_params = 0)
        { 
                global $tree;
                
                $parent_id = (int) $tree->getParentId($a_node_id);
                
                if ($parent_id != 0)
                {
                        $obj_data =& $this->ilias->obj_factory->getInstanceByRefId($a_node_id);
                        $obj_data->notify($a_event,$a_ref_id,$a_parent_non_rbac_id,$parent_id,$a_params);
                }
                                
                return true;
        }
        
        // toggle subscription interface
        function setRegisterMode($a_bool)
        {
                $this->register = (bool) $a_bool;
        }
        
        // check register status of current user
        // abstract method; overwrite in object type class
        function isUserRegistered($a_user_id = 0)
        {
                return false;
        }

        function requireRegistration()
        {
                return $this->register;
        }


        function getXMLZip()
        {
                return false;
        }
        function getHTMLDirectory()
        {
                return false;
        }


} // END class.ilObject
?>