survey/classes/class.ilObjSurvey.php

Go to the documentation of this file.

<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2006 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. |
        +-----------------------------------------------------------------------------+
*/

include_once "./classes/class.ilObject.php";
include_once "./survey/classes/inc.SurveyConstants.php";

class ilObjSurvey extends ilObject
{
  var $survey_id;

  var $author;

  var $introduction;

  var $outro;

  var $status;

  var $evaluation_access;

  var $start_date;

        var $startdate_enabled;

  var $end_date;

        var $enddate_enabled;

        var $questions;

        var $invitation;

        var $invitation_mode;
        
        var $anonymize;

        var $display_question_titles;

        function ilObjSurvey($a_id = 0,$a_call_by_reference = true)
        {
                global $ilUser;
                $this->type = "svy";
                $this->ilObject($a_id,$a_call_by_reference);

                $this->survey_id = -1;
                $this->introduction = "";
                $this->outro = $this->lng->txt("survey_finished");
                $this->author = $ilUser->fullname;
                $this->status = STATUS_OFFLINE;
                $this->evaluation_access = EVALUATION_ACCESS_OFF;
                $this->startdate_enabled = 0;
                $this->enddate_enabled = 0;
                $this->questions = array();
                $this->invitation = INVITATION_OFF;
                $this->invitation_mode = MODE_PREDEFINED_USERS;
                $this->anonymize = ANONYMIZE_OFF;
                $this->display_question_titles = QUESTIONTITLES_VISIBLE;
        }

        function create($a_upload = false)
        {
                parent::create();
                $this->createMetaData();
        }

        function update()
        {
                $this->updateMetaData();

                if (!parent::update())
                {
                        return false;
                }

                // put here object specific stuff

                return true;
        }

        function createReference() 
        {
                $result = parent::createReference();
                $this->saveToDb();
                return $result;
        }

        function read($a_force_db = false)
        {
                parent::read($a_force_db);
                $this->loadFromDb();
        }

        function ilClone($a_parent_ref)
        {               
                global $rbacadmin;

                // always call parent ilClone function first!!
                $new_ref_id = parent::ilClone($a_parent_ref);
                
                // get object instance of ilCloned object
                //$newObj =& $this->ilias->obj_factory->getInstanceByRefId($new_ref_id);

                // create a local role folder & default roles
                //$roles = $newObj->initDefaultRoles();

                // ...finally assign role to creator of object
                //$rbacadmin->assignUser($roles[0], $newObj->getOwner(), "n");          

                // always destroy objects in ilClone method because ilClone() is recursive and creates instances for each object in subtree!
                //unset($newObj);

                // ... and finally always return new reference ID!!
                return $new_ref_id;
        }

        function delete()
        {
                $remove = parent::delete();
                // always call parent delete function first!!
                if (!$remove)
                {
                        return false;
                }

                $this->deleteMetaData();

                // Delete all survey questions, constraints and materials
                foreach ($this->questions as $question_id)
                {
                        $this->removeQuestion($question_id);
                }
                $this->deleteSurveyRecord();
                
                return true;
        }
        
        function deleteSurveyRecord()
        {
                global $ilDB;
                
                $query = sprintf("DELETE FROM survey_survey WHERE survey_id = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);

                $query = sprintf("SELECT questionblock_fi FROM survey_questionblock_question WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                $questionblocks = array();
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        array_push($questionblocks, $row["questionblock_fi"]);
                }
                if (count($questionblocks))
                {
                        $query = "DELETE FROM survey_questionblock WHERE questionblock_id IN (" . join($questionblocks, ",") . ")";
                        $result = $ilDB->query($query);
                }
                $query = sprintf("DELETE FROM survey_questionblock_question WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                
                $this->deleteAllUserData();

                // delete export files
                include_once "./classes/class.ilUtil.php";
                $svy_data_dir = ilUtil::getDataDir()."/svy_data";
                $directory = $svy_data_dir."/svy_".$this->getId();
                if (is_dir($directory))
                {
                        include_once "./classes/class.ilUtil.php";
                        ilUtil::delDir($directory);
                }

                include_once("./content/classes/Media/class.ilObjMediaObject.php");
                $mobs = ilObjMediaObject::_getMobsOfObject("svy:html", $this->getId());
                // remaining usages are not in text anymore -> delete them
                // and media objects (note: delete method of ilObjMediaObject
                // checks whether object is used in another context; if yes,
                // the object is not deleted!)
                foreach($mobs as $mob)
                {
                        ilObjMediaObject::_removeUsage($mob, "svy:html", $this->getId());
                        $mob_obj =& new ilObjMediaObject($mob);
                        $mob_obj->delete();
                }
        }
        
        function deleteAllUserData()
        {
                global $ilDB, $ilLog;
                
                $query = sprintf("DELETE FROM survey_finished WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                if ($result != DB_OK)
                {
                        $ilLog->write("SURVEY MAINTENANCE ERROR: $query failed!");
                }

                $query = sprintf("DELETE FROM survey_answer WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                if ($result != DB_OK)
                {
                        $ilLog->write("SURVEY MAINTENANCE ERROR: $query failed!");
                }
        }
        
        function removeSelectedSurveyResults($finished_ids)
        {
                global $ilDB;
                
                foreach ($finished_ids as $finished_id)
                {
                        $query = sprintf("SELECT * FROM survey_finished WHERE finished_id = %s",
                                $ilDB->quote($finished_id . "")
                        );
                        $result = $ilDB->query($query);
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);

                        if (strlen($row["anonymous_id"]) > 0)
                        {
                                $query = sprintf("DELETE FROM survey_answer WHERE survey_fi = %s AND anonymous_id = %s",
                                        $ilDB->quote($this->getSurveyId()),
                                        $ilDB->quote($row["anonymous_id"] . "")
                                );
                        }
                        else
                        {
                                $query = sprintf("DELETE FROM survey_answer WHERE survey_fi = %s AND user_fi = %s AND anonymous_id = %s",
                                        $ilDB->quote($this->getSurveyId()),
                                        $ilDB->quote($row["user_fi"] . ""),
                                        $ilDB->quote($row["anonymous_id"] . "")
                                );
                        }
                        $result = $ilDB->query($query);

                        $query = sprintf("DELETE FROM survey_finished WHERE finished_id = %s",
                                $ilDB->quote($finished_id . "")
                        );
                        $result = $ilDB->query($query);
                }
        }
        
        function &getSurveyParticipants()
        {
                global $ilDB;
                
                $query = sprintf("SELECT * FROM survey_finished WHERE survey_fi = %s ORDER BY user_fi",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                $participants = array();
                if ($result->numRows() > 0)
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                if (($row["user_fi"] > 0) && ($row["user_fi"] != ANONYMOUS_USER_ID) && (!strlen($row["anonymous_id"])))
                                {
                                        $uname = ilObjUser::_lookupName($row["user_fi"]);
                                        if (strlen($uname["user_id"]))
                                        {
                                                $login = ilObjUser::_lookupLogin($row["user_fi"]);
                                                $participants[$row["finished_id"]] = array("name" => $uname["lastname"] . ", " . $uname["firstname"], "login" => $login);
                                        }
                                        else
                                        {
                                                $participants[$row["finished_id"]] = array("name" => $this->lng->txt("deleted_user"));
                                        }
                                }
                                else
                                {
                                        if (strlen($row["anonymous_id"]) > 0)
                                        {
                                                $participants[$row["finished_id"]] = array("name" => $this->lng->txt("anonymous"));
                                        }
                                }
                        }
                }
                return $participants;
        }

        function notify($a_event,$a_ref_id,$a_parent_non_rbac_id,$a_node_id,$a_params = 0)
        {
                global $tree;
                
                switch ($a_event)
                {
                        case "link":
                                
                                //var_dump("<pre>",$a_params,"</pre>");
                                //echo "Module name ".$this->getRefId()." triggered by link event. Objects linked into target object ref_id: ".$a_ref_id;
                                //exit;
                                break;
                        
                        case "cut":
                                
                                //echo "Module name ".$this->getRefId()." triggered by cut event. Objects are removed from target object ref_id: ".$a_ref_id;
                                //exit;
                                break;
                                
                        case "copy":
                        
                                //var_dump("<pre>",$a_params,"</pre>");
                                //echo "Module name ".$this->getRefId()." triggered by copy event. Objects are copied into target object ref_id: ".$a_ref_id;
                                //exit;
                                break;

                        case "paste":
                                
                                //echo "Module name ".$this->getRefId()." triggered by paste (cut) event. Objects are pasted into target object ref_id: ".$a_ref_id;
                                //exit;
                                break;
                        
                        case "new":
                                
                                //echo "Module name ".$this->getRefId()." triggered by paste (new) event. Objects are applied to target object ref_id: ".$a_ref_id;
                                //exit;
                                break;
                }
                
                // At the beginning of the recursive process it avoids second call of the notify function with the same parameter
                if ($a_node_id==$_GET["ref_id"])
                {       
                        $parent_obj =& $this->ilias->obj_factory->getInstanceByRefId($a_node_id);
                        $parent_type = $parent_obj->getType();
                        if($parent_type == $this->getType())
                        {
                                $a_node_id = (int) $tree->getParentId($a_node_id);
                        }
                }
                
                parent::notify($a_event,$a_ref_id,$a_parent_non_rbac_id,$a_node_id,$a_params);
        }

        function isComplete()
        {
                if (($this->getTitle()) and ($this->author) and (count($this->questions)))
                {
                        return true;
                } 
                        else 
                {
                        return false;
                }
        }

        function _isComplete($obj_id)
        {
                $survey = new ilObjSurvey($obj_id, false);
                $survey->loadFromDb();
                if (($survey->getTitle()) and ($survey->author) and (count($survey->questions)))
                {
                        return true;
                } 
                        else 
                {
                        return false;
                }
        }

        function &_getGlobalSurveyData($obj_id)
        {
                $survey = new ilObjSurvey($obj_id, false);
                $survey->loadFromDb();
                $result = array();
                if (($survey->getTitle()) and ($survey->author) and (count($survey->questions)))
                {
                        $result["complete"] = true;
                } 
                        else 
                {
                        $result["complete"] = false;
                }
                $result["evaluation_access"] = $survey->getEvaluationAccess();
                return $result;
        }

        function saveCompletionStatus() 
        {
                global $ilDB;
                
                $complete = 0;
                if ($this->isComplete()) 
                {
                        $complete = 1;
                }
    if ($this->survey_id > 0) 
                {
                        $query = sprintf("UPDATE survey_survey SET complete = %s WHERE survey_id = %s",
                                $ilDB->quote("$complete"),
                                $ilDB->quote($this->survey_id) 
                        );
      $result = $ilDB->query($query);
                }
        }

        function duplicateQuestionForSurvey($question_id)
        {
                global $ilUser;
                
                $questiontype = $this->getQuestionType($question_id);
                $question_gui = $this->getQuestionGUI($questiontype, $question_id);
                $duplicate_id = $question_gui->object->duplicate(true);
                return $duplicate_id;
        }

        function insertQuestion($question_id) 
        {
                global $ilDB;
                
                include_once "./survey/classes/class.SurveyQuestion.php";
                if (!SurveyQuestion::_isComplete($question_id))
                {
                        return FALSE;
                }
                else
                {
                        // get maximum sequence index in test
                        $query = sprintf("SELECT survey_question_id FROM survey_survey_question WHERE survey_fi = %s",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                        $sequence = $result->numRows();
                        $duplicate_id = $this->duplicateQuestionForSurvey($question_id);
                        $query = sprintf("INSERT INTO survey_survey_question (survey_question_id, survey_fi, question_fi, sequence, TIMESTAMP) VALUES (NULL, %s, %s, %s, NULL)",
                                $ilDB->quote($this->getSurveyId()),
                                $ilDB->quote($duplicate_id),
                                $ilDB->quote($sequence)
                        );
                        $result = $ilDB->query($query);
                        if ($result != DB_OK) 
                        {
                                // Error
                        }
                        $this->loadQuestionsFromDb();
                        return TRUE;
                }
        }


        
        function insertQuestionblock($questionblock_id) 
        {
                global $ilDB;
                $query = sprintf("SELECT survey_questionblock.*, survey_survey.obj_fi, survey_question.title AS questiontitle, survey_survey_question.sequence, object_data.title as surveytitle, survey_question.question_id FROM object_reference, object_data, survey_questionblock, survey_questionblock_question, survey_survey, survey_question, survey_survey_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_survey.survey_id = survey_questionblock_question.survey_fi AND survey_questionblock_question.question_fi = survey_question.question_id AND survey_survey.obj_fi = object_reference.obj_id AND object_reference.obj_id = object_data.obj_id AND survey_survey_question.survey_fi = survey_survey.survey_id AND survey_survey_question.question_fi = survey_question.question_id AND survey_questionblock.questionblock_id =%s ORDER BY survey_survey_question.sequence",
                        $ilDB->quote($questionblock_id)
                );
                $result = $ilDB->query($query);
                $questions = array();
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        array_push($questions, $row["question_id"]);
                        $title = $row["title"];
                }
                $this->createQuestionblock($title, $questions);
        }
        
  function saveToDb()
  {
                global $ilDB;
                $complete = 0;
                if ($this->isComplete()) 
                {
                        $complete = 1;
                }
                $startdate = $this->getStartDate();
                if (!$startdate or !$this->startdate_enabled)
                {
                        $startdate = "NULL";
                }
                else
                {
                        $startdate = $ilDB->quote($startdate);
                }
                $enddate = $this->getEndDate();
                if (!$enddate or !$this->enddate_enabled)
                {
                        $enddate = "NULL";
                }
                else
                {
                        $enddate = $ilDB->quote($enddate);
                }

                // cleanup RTE images which are not inserted into the question text
                include_once("./Services/RTE/classes/class.ilRTE.php");
                ilRTE::_cleanupMediaObjectUsage($this->introduction . $this->getOutro(), $this->getType() . ":html", $this->getId());

    if ($this->survey_id == -1) 
                {
      // Write new dataset
      $now = getdate();
      $created = sprintf("%04d%02d%02d%02d%02d%02d", $now['year'], $now['mon'], $now['mday'], $now['hours'], $now['minutes'], $now['seconds']);
      $query = sprintf("INSERT INTO survey_survey (survey_id, obj_fi, author, introduction, outro, status, startdate, enddate, evaluation_access, invitation, invitation_mode, complete, created, anonymize, show_question_titles, TIMESTAMP) VALUES (NULL, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, NULL)",
                                $ilDB->quote($this->getId()),
                                $ilDB->quote($this->author . ""),
                                $ilDB->quote(ilRTE::_replaceMediaObjectImageSrc($this->introduction, 0)),
                                $ilDB->quote(ilRTE::_replaceMediaObjectImageSrc($this->getOutro(), 0)),
                                $ilDB->quote($this->status . ""),
                                $startdate,
                                $enddate,
                                $ilDB->quote($this->evaluation_access . ""),
                                $ilDB->quote($this->invitation . ""),
                                $ilDB->quote($this->invitation_mode . ""),
                                $ilDB->quote($complete . ""),
                                $ilDB->quote($this->getAnonymize() . ""),
                                $ilDB->quote($this->getShowQuestionTitles() . ""),
                                $ilDB->quote($created)
      );
      $result = $ilDB->query($query);
      if ($result == DB_OK) 
                        {
        $this->survey_id = $ilDB->getLastInsertId();
      }
    } 
                else 
                {
      // update existing dataset
                        $query = sprintf("UPDATE survey_survey SET author = %s, introduction = %s, outro = %s, status = %s, startdate = %s, enddate = %s, evaluation_access = %s, invitation = %s, invitation_mode = %s, complete = %s, anonymize = %s, show_question_titles = %s WHERE survey_id = %s",
                                $ilDB->quote($this->author . ""),
                                $ilDB->quote(ilRTE::_replaceMediaObjectImageSrc($this->introduction, 0)),
                                $ilDB->quote(ilRTE::_replaceMediaObjectImageSrc($this->getOutro(), 0)),
                                $ilDB->quote($this->status . ""),
                                $startdate,
                                $enddate,
                                $ilDB->quote($this->evaluation_access . ""),
                                $ilDB->quote($this->invitation . ""),
                                $ilDB->quote($this->invitation_mode . ""),
                                $ilDB->quote($complete . ""),
                                $ilDB->quote($this->getAnonymize() . ""),
                                $ilDB->quote($this->getShowQuestionTitles() . ""),
                                $ilDB->quote($this->survey_id)
      );
      $result = $ilDB->query($query);
    }
    if ($result == DB_OK) 
                {
                        // save questions to db
                        $this->saveQuestionsToDb();
    }
  }

        function saveQuestionsToDb() 
        {
                global $ilDB;
                // save old questions state
                $old_questions = array();
                $query = sprintf("SELECT * FROM survey_survey_question WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                $old_questions[$row["question_fi"]] = $row;
                        }
                }
                
                // delete existing question relations
    $query = sprintf("DELETE FROM survey_survey_question WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                // create new question relations
                foreach ($this->questions as $key => $value) 
                {
                        $query = sprintf("INSERT INTO survey_survey_question (survey_question_id, survey_fi, question_fi, heading, sequence, TIMESTAMP) VALUES (NULL, %s, %s, %s, %s, NULL)",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($value . ""),
                                $ilDB->quote($old_questions[$value]["heading"]),
                                $ilDB->quote($key . "")
                        );
                        $result = $ilDB->query($query);
                }
        }

        function getAnonymousId($id)
        {
                global $ilDB;
                $query = sprintf("SELECT anonymous_id FROM survey_answer WHERE anonymous_id = %s",
                        $ilDB->quote($id)
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        return $row["anonymous_id"];
                }
                else
                {
                        return "";
                }
        }

        function getQuestionGUI($questiontype, $question_id)
        {
                $questiontypegui = $questiontype . "GUI";
                include_once "./survey/classes/class.$questiontypegui.php";
                $question = new $questiontypegui();
                $question->object->loadFromDb($question_id);
                return $question;
        }
        
  function getQuestionType($question_id) 
        {
                global $ilDB;
    if ($question_id < 1) return -1;
    $query = sprintf("SELECT type_tag FROM survey_question, survey_questiontype WHERE survey_question.question_id = %s AND survey_question.questiontype_fi = survey_questiontype.questiontype_id",
      $ilDB->quote($question_id)
    );
    $result = $ilDB->query($query);
    if ($result->numRows() == 1) 
                {
      $data = $result->fetchRow(DB_FETCHMODE_OBJECT);
      return $data->type_tag;
    } 
                else 
                {
      return "";
    }
  }
        
        function getSurveyId()
        {
                return $this->survey_id;
        }
        
        function setAnonymize($a_anonymize)
        {
                $this->anonymize = $a_anonymize;
        }

        function getAnonymize()
        {
                return $this->anonymize;
        }
        
        function isAccessibleWithoutCode()
        {
                if ($this->getAnonymize() == ANONYMIZE_FREEACCESS)
                {
                        return true;
                }
                else
                {
                        return false;
                }
        }

  function loadFromDb()
  {
                global $ilDB;
    $query = sprintf("SELECT * FROM survey_survey WHERE obj_fi = %s",
      $ilDB->quote($this->getId())
    );
    $result = $ilDB->query($query);
    if (strcmp(strtolower(get_class($result)), db_result) == 0) 
                {
      if ($result->numRows() == 1) 
                        {
                                $data = $result->fetchRow(DB_FETCHMODE_OBJECT);
                                $this->survey_id = $data->survey_id;
                                $this->author = $data->author;
                                include_once("./Services/RTE/classes/class.ilRTE.php");
                                $this->introduction = ilRTE::_replaceMediaObjectImageSrc($data->introduction, 1);
                                if (strcmp($data->outro, "survey_finished") == 0)
                                {
                                        $this->setOutro($this->lng->txt("survey_finished"));
                                }
                                else
                                {
                                        $this->setOutro(ilRTE::_replaceMediaObjectImageSrc($data->outro, 1));
                                }
                                $this->status = $data->status;
                                $this->invitation = $data->invitation;
                                $this->invitation_mode = $data->invitation_mode;
                                $this->display_question_titles = $data->show_question_titles;
                                $this->start_date = $data->startdate;
                                if (!$data->startdate)
                                {
                                        $this->startdate_enabled = 0;
                                }
                                else
                                {
                                        $this->startdate_enabled = 1;
                                }
        $this->end_date = $data->enddate;
                                if (!$data->enddate)
                                {
                                        $this->enddate_enabled = 0;
                                }
                                else
                                {
                                        $this->enddate_enabled = 1;
                                }
                                switch ($data->anonymize)
                                {
                                        case ANONYMIZE_OFF:
                                        case ANONYMIZE_ON:
                                        case ANONYMIZE_FREEACCESS:
                                                $this->setAnonymize($data->anonymize);
                                                break;
                                        default:
                                                $this->setAnonymize(ANONYMIZE_OFF);
                                                break;
                                }
        $this->evaluation_access = $data->evaluation_access;
                                $this->loadQuestionsFromDb();
      }
    }
        }

        function loadQuestionsFromDb() 
        {
                global $ilDB;
                $this->questions = array();
                $query = sprintf("SELECT * FROM survey_survey_question WHERE survey_fi = %s ORDER BY sequence",
                        $ilDB->quote($this->survey_id)
                );
                $result = $ilDB->query($query);
                while ($data = $result->fetchRow(DB_FETCHMODE_OBJECT)) 
                {
                        $this->questions[$data->sequence] = $data->question_fi;
                }
        }

        function setStartDateEnabled($enabled = false)
        {
                if ($enabled)
                {
                        $this->startdate_enabled = 1;
                }
                else
                {
                        $this->startdate_enabled = 0;
                }
        }
        
        function getStartDateEnabled()
        {
                return $this->startdate_enabled;
        }

        function setEndDateEnabled($enabled = false)
        {
                if ($enabled)
                {
                        $this->enddate_enabled = 1;
                }
                else
                {
                        $this->enddate_enabled = 0;
                }
        }
        
        function getEndDateEnabled()
        {
                return $this->enddate_enabled;
        }

        function setAuthor($author = "") 
        {
    if (!$author) 
                {
      $author = $this->ilias->account->fullname;
    }
    $this->author = $author;
  }

  function getShowQuestionTitles() 
        {
                return $this->display_question_titles;
  }

  function showQuestionTitles() 
        {
                $this->display_question_titles = QUESTIONTITLES_VISIBLE;
  }

  function hideQuestionTitles() 
        {
                $this->display_question_titles = QUESTIONTITLES_HIDDEN;
  }
        
  function setInvitation($invitation = 0) 
        {
                global $ilDB;
    $this->invitation = $invitation;
                // remove the survey from the personal desktops
                $query = sprintf("DELETE FROM desktop_item WHERE type = %s AND item_id = %s",
                        $ilDB->quote("svy"),
                        $ilDB->quote($this->getRefId())
                );
                $result = $ilDB->query($query);
                if ($invitation == INVITATION_OFF)
                {
                        // already removed prior
                }
                else if ($invitation == INVITATION_ON)
                {
                        if ($this->getInvitationMode() == MODE_UNLIMITED)
                        {
                                $query = "SELECT usr_id FROM usr_data";
                                $result = $ilDB->query($query);
                                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                                {
                                        $query = sprintf("INSERT INTO desktop_item (user_id, item_id, type, parameters) VALUES (%s, %s, %s, NULL)",
                                                $ilDB->quote($row["usr_id"]),
                                                $ilDB->quote($this->getRefId()),
                                                $ilDB->quote("svy")
                                        );
                                        $insertresult = $ilDB->query($query);
                                }
                        }
                        else
                        {
                                $query = sprintf("SELECT user_fi FROM survey_invited_user WHERE survey_fi = %s",
                                        $ilDB->quote($this->getSurveyId())
                                );
                                $result = $ilDB->query($query);
                                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                                {
                                        $query = sprintf("INSERT INTO desktop_item (user_id, item_id, type, parameters) VALUES (%s, %s, %s, NULL)",
                                                $ilDB->quote($row["user_fi"]),
                                                $ilDB->quote($this->getRefId()),
                                                $ilDB->quote("svy")
                                        );
                                        $insertresult = $ilDB->query($query);
                                }
                                $query = sprintf("SELECT group_fi FROM survey_invited_group WHERE survey_fi = %s",
                                        $ilDB->quote($this->getSurveyId())
                                );
                                $result = $ilDB->query($query);
                                include_once "./classes/class.ilObjGroup.php";
                                include_once "./classes/class.ilObjUser.php";
                                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                                {
                                        $group = new ilObjGroup($row["group_fi"]);
                                        $members = $group->getGroupMemberIds();
                                        foreach ($members as $user_id)
                                        {
                                                if (ilObjUser::_lookupLogin($user_id))
                                                {
                                                        $user = new ilObjUser($user_id);
                                                        $user->addDesktopItem($this->getRefId(), "svy");
                                                }
                                        }
                                }
                        }
                }
  }

  function setInvitationMode($invitation_mode = 0) 
        {
                global $ilDB;
    $this->invitation_mode = $invitation_mode;
                if ($invitation_mode == MODE_UNLIMITED)
                {
                        $query = sprintf("DELETE FROM survey_invited_group WHERE survey_fi = %s",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                        $query = sprintf("DELETE FROM survey_invited_user WHERE survey_fi = %s",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                }
                // add/remove the survey from personal desktops -> calling getInvitation with the same value makes all changes for the new invitation mode
                $this->setInvitation($this->getInvitation());
  }
        
        function setInvitationAndMode($invitation = 0, $invitation_mode = 0)
        {
                global $ilDB;
    $this->invitation_mode = $invitation_mode;
                if ($invitation_mode == MODE_UNLIMITED)
                {
                        $query = sprintf("DELETE FROM survey_invited_group WHERE survey_fi = %s",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                        $query = sprintf("DELETE FROM survey_invited_user WHERE survey_fi = %s",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                }
                // add/remove the survey from personal desktops -> calling getInvitation with the same value makes all changes for the new invitation mode
                $this->setInvitation($invitation);
        }

  function setIntroduction($introduction = "") 
        {
    $this->introduction = $introduction;
  }

  function setOutro($outro = "") 
        {
    $this->outro = $outro;
  }

  function getAuthor() 
        {
    return $this->author;
  }

  function getInvitation() 
        {
    return $this->invitation;
  }

  function getInvitationMode() 
        {
    return $this->invitation_mode;
  }

  function getStatus() 
        {
    return $this->status;
  }

  function isOnline() 
        {
    if ($this->status == STATUS_ONLINE)
                {
                        return true;
                }
                else
                {
                        return false;
                }
  }

  function isOffline() 
        {
    if ($this->status == STATUS_OFFLINE)
                {
                        return true;
                }
                else
                {
                        return false;
                }
  }

  function setStatus($status = STATUS_OFFLINE) 
        {
                $result = "";
                if (($status == STATUS_ONLINE) && (count($this->questions) == 0))
                {
        $this->status = STATUS_OFFLINE;
                        $result = $this->lng->txt("cannot_switch_to_online_no_questions");
                }
                else
                {
        $this->status = $status;
                }
                return $result;
  }

  function getStartDate() 
        {
    return $this->start_date;
  }

        function canStartSurvey($anonymous_id)
        {
                global $ilAccess;
                
                $result = TRUE;
                $messages = array();
                // check start date
                if ($this->getStartDateEnabled())
                {
                        $epoch_time = mktime(0, 0, 0, $this->getStartMonth(), $this->getStartDay(), $this->getStartYear());
                        $now = mktime();
                        if ($now < $epoch_time) 
                        {
                                array_push($messages, $this->lng->txt("start_date_not_reached") . " (".ilFormat::formatDate(ilFormat::ftimestamp2dateDB($this->getStartYear().$this->getStartMonth().$this->getStartDay()."000000"), "date") . ")");
                                $result = FALSE;
                        }
                }
                // check end date
                if ($this->getEndDateEnabled())
                {
                        $epoch_time = mktime(0, 0, 0, $this->getEndMonth(), $this->getEndDay(), $this->getEndYear());
                        $now = mktime();
                        if ($now > $epoch_time) 
                        {
                                array_push($messages, $this->lng->txt("end_date_reached") . " (".ilFormat::formatDate(ilFormat::ftimestamp2dateDB($this->getEndYear().$this->getEndMonth().$this->getEndDay()."000000"), "date") . ")");
                                $result = FALSE;
                        }
                }
                // check online status
                if ($this->getStatus() == STATUS_OFFLINE)
                {
                        array_push($messages, $this->lng->txt("survey_is_offline"));
                        $result = FALSE;
                }
                // check rbac permissions
                if ((!$ilAccess->checkAccess("read", "", $this->ref_id)) || (!$ilAccess->checkAccess("participate", "", $this->ref_id)))
                {
                        array_push($messages, $this->lng->txt("cannot_participate_survey"));
                        $result = FALSE;
                }
                // 2. check previous access
                if (!$result["error"])
                {
                        global $ilUser;
                        $survey_started = $this->isSurveyStarted($ilUser->getId(), $anonymous_id);
                        if ($survey_started === 1)
                        {
                                array_push($messages, $this->lng->txt("already_completed_survey"));
                                $result = FALSE;
                        }
                }
                return array(
                        "result" => $result,
                        "messages" => $messages
                );
        }


  function setStartDate($start_date = "") 
        {
    $this->start_date = $start_date;
  }

  function getStartMonth() 
        {
                if (preg_match("/(\d{4})-(\d{2})-(\d{2})/", $this->start_date, $matches))
                {
                        return $matches[2];
                }
                else
                {
                        return "";
                }
  }

  function getStartDay() 
        {
                if (preg_match("/(\d{4})-(\d{2})-(\d{2})/", $this->start_date, $matches))
                {
                        return $matches[3];
                }
                else
                {
                        return "";
                }
  }

  function getStartYear() 
        {
                if (preg_match("/(\d{4})-(\d{2})-(\d{2})/", $this->start_date, $matches))
                {
                        return $matches[1];
                }
                else
                {
                        return "";
                }
  }

  function getEndDate() 
        {
    return $this->end_date;
  }

  function setEndDate($end_date = "") 
        {
    $this->end_date = $end_date;
  }

  function getEndMonth() 
        {
                if (preg_match("/(\d{4})-(\d{2})-(\d{2})/", $this->end_date, $matches))
                {
                        return $matches[2];
                }
                else
                {
                        return "";
                }
  }

  function getEndDay() 
        {
                if (preg_match("/(\d{4})-(\d{2})-(\d{2})/", $this->end_date, $matches))
                {
                        return $matches[3];
                }
                else
                {
                        return "";
                }
  }

  function getEndYear() 
        {
                if (preg_match("/(\d{4})-(\d{2})-(\d{2})/", $this->end_date, $matches))
                {
                        return $matches[1];
                }
                else
                {
                        return "";
                }
  }

  function getEvaluationAccess() 
        {
    return $this->evaluation_access;
  }

  function setEvaluationAccess($evaluation_access = EVALUATION_ACCESS_OFF) 
        {
    $this->evaluation_access = $evaluation_access;
  }

  function getIntroduction() 
        {
    return $this->introduction;
  }

  function getOutro() 
        {
    return $this->outro;
  }

        function &getExistingQuestions() 
        {
                global $ilDB;
                $existing_questions = array();
                $query = sprintf("SELECT survey_question.original_id FROM survey_question, survey_survey_question WHERE survey_survey_question.survey_fi = %s AND survey_survey_question.question_fi = survey_question.question_id",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($data = $result->fetchRow(DB_FETCHMODE_OBJECT)) 
                {
                        array_push($existing_questions, $data->original_id);
                }
                return $existing_questions;
        }

        function &getQuestionpoolTitles() 
        {
                global $rbacsystem;
                global $ilDB;
                
                $qpl_titles = array();
                // get all available questionpools and remove the trashed questionspools
                $query = "SELECT object_data.*, object_data.obj_id, object_reference.ref_id FROM object_data, object_reference WHERE object_data.obj_id = object_reference.obj_id AND object_data.type = 'spl'";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {               
                        if ($rbacsystem->checkAccess("write", $row->ref_id) && ($this->_hasUntrashedReference($row->obj_id)))
                        {
                                include_once("./survey/classes/class.ilObjSurveyQuestionPool.php");
                                if (ilObjSurveyQuestionPool::_lookupOnline($row->obj_id))
                                {
                                        $qpl_titles["$row->obj_id"] = $row->title;
                                }
                        }
                }
                return $qpl_titles;
        }
        
        function moveUpQuestion($question_id)
        {
                $move_questions = array($question_id);
                $pages =& $this->getSurveyPages();
                $pageindex = -1;
                foreach ($pages as $idx => $page)
                {
                        if ($page[0]["question_id"] == $question_id)
                        {
                                $pageindex = $idx;
                        }
                }
                if ($pageindex > 0)
                {
                        $this->moveQuestions($move_questions, $pages[$pageindex-1][0]["question_id"], 0);
                }
                else
                {
                        // move up a question in a questionblock
                        $questions = $this->getSurveyQuestions();
                        $questions = array_keys($questions);
                        $index = array_search($question_id, $questions);
                        if (($index !== FALSE) && ($index > 0))
                        {
                                $this->moveQuestions($move_questions, $questions[$index-1], 0);
                        }
                }
        }
        
        function moveDownQuestion($question_id)
        {
                $move_questions = array($question_id);
                $pages =& $this->getSurveyPages();
                $pageindex = -1;
                foreach ($pages as $idx => $page)
                {
                        if (($page[0]["question_id"] == $question_id) && (strcmp($page[0]["questionblock_id"], "") == 0))
                        {
                                $pageindex = $idx;
                        }
                }
                if (($pageindex < count($pages)-1) && ($pageindex >= 0))
                {
                        $this->moveQuestions($move_questions, $pages[$pageindex+1][count($pages[$pageindex+1])-1]["question_id"], 1);
                }
                else
                {
                        // move down a question in a questionblock
                        $questions = $this->getSurveyQuestions();
                        $questions = array_keys($questions);
                        $index = array_search($question_id, $questions);
                        if (($index !== FALSE) && ($index < count($questions)-1))
                        {
                                $this->moveQuestions($move_questions, $questions[$index+1], 1);
                        }
                }
        }
        
        function moveUpQuestionblock($questionblock_id)
        {
                $pages =& $this->getSurveyPages();
                $move_questions = array();
                $pageindex = -1;
                foreach ($pages as $idx => $page)
                {
                        if ($page[0]["questionblock_id"] == $questionblock_id)
                        {
                                foreach ($page as $pageidx => $question)
                                {
                                        array_push($move_questions, $question["question_id"]);
                                }
                                $pageindex = $idx;
                        }
                }
                if ($pageindex > 0)
                {
                        $this->moveQuestions($move_questions, $pages[$pageindex-1][0]["question_id"], 0);
                }
        }
        
        function moveDownQuestionblock($questionblock_id)
        {
                $pages =& $this->getSurveyPages();
                $move_questions = array();
                $pageindex = -1;
                foreach ($pages as $idx => $page)
                {
                        if ($page[0]["questionblock_id"] == $questionblock_id)
                        {
                                foreach ($page as $pageidx => $question)
                                {
                                        array_push($move_questions, $question["question_id"]);
                                }
                                $pageindex = $idx;
                        }
                }
                if ($pageindex < count($pages)-1)
                {
                        $this->moveQuestions($move_questions, $pages[$pageindex+1][count($pages[$pageindex+1])-1]["question_id"], 1);
                }
        }
        
        function moveQuestions($move_questions, $target_index, $insert_mode)
        {
                $array_pos = array_search($target_index, $this->questions);
                if ($insert_mode == 0)
                {
                        $part1 = array_slice($this->questions, 0, $array_pos);
                        $part2 = array_slice($this->questions, $array_pos);
                }
                else if ($insert_mode == 1)
                {
                        $part1 = array_slice($this->questions, 0, $array_pos + 1);
                        $part2 = array_slice($this->questions, $array_pos + 1);
                }
                foreach ($move_questions as $question_id)
                {
                        if (!(array_search($question_id, $part1) === FALSE))
                        {
                                unset($part1[array_search($question_id, $part1)]);
                        }
                        if (!(array_search($question_id, $part2) === FALSE))
                        {
                                unset($part2[array_search($question_id, $part2)]);
                        }
                }
                $part1 = array_values($part1);
                $part2 = array_values($part2);
                $this->questions = array_values(array_merge($part1, $move_questions, $part2));
                foreach ($move_questions as $question_id)
                {
                        $constraints = $this->getConstraints($question_id);
                        foreach ($constraints as $idx => $constraint)
                        {
                                foreach ($part2 as $next_question_id)
                                {
                                        if ($constraint["question"] == $next_question_id)
                                        {
                                                // constraint concerning a question that follows -> delete constraint
                                                $this->deleteConstraint($constraint["id"], $question_id);
                                        }
                                }
                        }
                }
                $this->saveQuestionsToDb();
        }
        
        function removeQuestion($question_id)
        {
                include_once "./survey/classes/class.SurveyQuestion.php";
                $question =& $this->_instanciateQuestion($question_id);
                $question->delete($question_id);
                $this->removeConstraintsConcerningQuestion($question_id);
        }
        
        function removeConstraintsConcerningQuestion($question_id)
        {
                global $ilDB;
                $query = sprintf("SELECT constraint_fi FROM survey_question_constraint WHERE question_fi = %s AND survey_fi = %s",
                        $ilDB->quote($question_id . ""),
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows() > 0)
                {
                        $remove_constraints = array();
                        while ($row = $result->fetchRow(DB_FETCHMODE_HASHREF))
                        {
                                array_push($remove_constraints, $row["constraint_fi"]);
                        }
                        $query = sprintf("DELETE FROM survey_question_constraint WHERE question_fi = %s AND survey_fi = %s",
                                $ilDB->quote($question_id . ""),
                                $ilDB->quote($this->getSurveyId() . "")
                        );
                        $result = $ilDB->query($query);
                        foreach ($remove_constraints as $key => $constraint_id)
                        {
                                $query = sprintf("DELETE FROM survey_constraint WHERE constraint_id = %s",
                                        $ilDB->quote($constraint_id . "")
                                );
                                $result = $ilDB->query($query);
                        }
                }
        }
                
        function removeQuestions($remove_questions, $remove_questionblocks)
        {
                global $ilDB;
                $questions =& $this->getSurveyQuestions();
                foreach ($questions as $question_id => $data)
                {
                        if (in_array($question_id, $remove_questions) or in_array($data["questionblock_id"], $remove_questionblocks))
                        {
                                unset($this->questions[array_search($question_id, $this->questions)]);
                                $this->removeQuestion($question_id);
                        }
                }
                foreach ($remove_questionblocks as $questionblock_id)
                {
                        $query = sprintf("DELETE FROM survey_questionblock WHERE questionblock_id = %s",
                                $ilDB->quote($questionblock_id)
                        );
                        $result = $ilDB->query($query);
                        $query = sprintf("DELETE FROM survey_questionblock_question WHERE questionblock_fi = %s AND survey_fi = %s",
                                $ilDB->quote($questionblock_id),
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                }
                $this->questions = array_values($this->questions);
                $this->saveQuestionsToDb();
        }
                
        function unfoldQuestionblocks($questionblocks)
        {
                global $ilDB;
                foreach ($questionblocks as $index)
                {
                        $query = sprintf("DELETE FROM survey_questionblock WHERE questionblock_id = %s",
                                $ilDB->quote($index)
                        );
                        $result = $ilDB->query($query);
                        $query = sprintf("DELETE FROM survey_questionblock_question WHERE questionblock_fi = %s AND survey_fi = %s",
                                $ilDB->quote($index),
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                }
        }
        
        function &getQuestionblockTitles()
        {
                global $ilDB;
                $titles = array();
                $query = sprintf("SELECT survey_questionblock.* FROM survey_questionblock, survey_question, survey_questionblock_question WHERE survey_questionblock_question.question_fi = survey_question.question_id AND survey_question.obj_fi = %s",
                        $ilDB->quote($this->getId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $titles[$row->questionblock_id] = $row->title;
                }
                return $titles;
        }
        
        function &getQuestionblockQuestions($questionblock_id)
        {
                global $ilDB;
                $titles = array();
                $query = sprintf("SELECT survey_question.title, survey_questionblock_question.question_fi, survey_questionblock_question.survey_fi FROM survey_questionblock, survey_questionblock_question, survey_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_question.question_id = survey_questionblock_question.question_fi AND survey_questionblock.questionblock_id = %s",
                        $ilDB->quote($questionblock_id)
                );
                $result = $ilDB->query($query);
                $survey_id = "";
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $titles[$row["question_fi"]] = $row["title"];
                        $survey_id = $row["survey_fi"];
                }
                $query = sprintf("SELECT question_fi, sequence FROM survey_survey_question WHERE survey_fi = %s ORDER BY sequence",
                        $ilDB->quote($survey_id . "")
                );
                $result = $ilDB->query($query);
                $resultarray = array();
                $counter = 1;
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        if (array_key_exists($row["question_fi"], $titles))
                        {
                                $resultarray[$counter++] = $titles[$row["question_fi"]];
                        }
                }
                return $resultarray;
        }
        
        function &getQuestionblockQuestionIds($questionblock_id)
        {
                global $ilDB;
                $ids = array();
                $query = sprintf("SELECT survey_questionblock.*, survey_survey.obj_fi, survey_question.question_id AS questiontitle, survey_survey_question.sequence, object_data.title as surveytitle, survey_question.question_id FROM object_reference, object_data, survey_questionblock, survey_questionblock_question, survey_survey, survey_question, survey_survey_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_survey.survey_id = survey_questionblock_question.survey_fi AND survey_questionblock_question.question_fi = survey_question.question_id AND survey_survey.obj_fi = object_reference.obj_id AND object_reference.obj_id = object_data.obj_id AND survey_survey_question.survey_fi = survey_survey.survey_id AND survey_survey_question.question_fi = survey_question.question_id AND survey_survey.obj_fi = %s AND survey_questionblock.questionblock_id = %s ORDER BY survey_survey_question.sequence ASC",
                        $ilDB->quote($this->getId()),
                        $ilDB->quote($questionblock_id)
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        array_push($ids, $row->question_id);
                }
                return $ids;
        }
        
        function getQuestionblock($questionblock_id)
        {
                global $ilDB;
                $query = sprintf("SELECT * FROM survey_questionblock WHERE questionblock_id = %s",
                        $ilDB->quote($questionblock_id)
                );
                $result = $ilDB->query($query);
                $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                return $row;
        }
        
        function _getQuestionblock($questionblock_id)
        {
                global $ilDB;
                $query = sprintf("SELECT * FROM survey_questionblock WHERE questionblock_id = %s",
                        $ilDB->quote($questionblock_id)
                );
                $result = $ilDB->query($query);
                $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                return $row;
        }

        function _addQuestionblock($title = "", $owner = 0)
        {
                global $ilDB;
                $query = sprintf("INSERT INTO survey_questionblock (questionblock_id, title, owner_fi, TIMESTAMP) VALUES (NULL, %s, %s, NULL)",
                        $ilDB->quote($title . ""),
                        $ilDB->quote($owner . "")
                );
                $result = $ilDB->query($query);
                return $ilDB->getLastInsertId();
        }
        
        function createQuestionblock($title, $questions)
        {
                global $ilDB;
                // if the selected questions are not in a continous selection, move all questions of the
                // questionblock at the position of the first selected question
                $this->moveQuestions($questions, $questions[0], 0);
                
                // now save the question block
                global $ilUser;
                $query = sprintf("INSERT INTO survey_questionblock (questionblock_id, title, owner_fi, TIMESTAMP) VALUES (NULL, %s, %s, NULL)",
                        $ilDB->quote($title),
                        $ilDB->quote($ilUser->id)
                );
                $result = $ilDB->query($query);
                if ($result == DB_OK) {
                        $questionblock_id = $ilDB->getLastInsertId();
                        foreach ($questions as $index)
                        {
                                $query = sprintf("INSERT INTO survey_questionblock_question (questionblock_question_id, survey_fi, questionblock_fi, question_fi) VALUES (NULL, %s, %s, %s)",
                                        $ilDB->quote($this->getSurveyId()),
                                        $ilDB->quote($questionblock_id),
                                        $ilDB->quote($index)
                                );
                                $result = $ilDB->query($query);
                                $this->deleteConstraints($index);
                        }
                }
        }
        
        function modifyQuestionblock($questionblock_id, $title)
        {
                global $ilDB;
                $query = sprintf("UPDATE survey_questionblock SET title = %s WHERE questionblock_id = %s",
                        $ilDB->quote($title),
                        $ilDB->quote($questionblock_id)
                );
                $result = $ilDB->query($query);
        }
        
        function deleteConstraints($question_id)
        {
                global $ilDB;
                $query = sprintf("SELECT * FROM survey_question_constraint WHERE question_fi = %s AND survey_fi = %s",
                        $ilDB->quote($question_id),
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $query = sprintf("DELETE FROM survey_constraint WHERE constraint_id = %s",
                                $ilDB->quote($row->constraint_fi)
                        );
                        $delresult = $ilDB->query($query);
                }
                $query = sprintf("DELETE FROM survey_question_constraint WHERE question_fi = %s AND survey_fi = %s",
                        $ilDB->quote($question_id),
                        $ilDB->quote($this->getSurveyId())
                );
                $delresult = $ilDB->query($query);
        }

        function deleteConstraint($constraint_id, $question_id)
        {
                global $ilDB;
                $query = sprintf("DELETE FROM survey_constraint WHERE constraint_id = %s",
                        $ilDB->quote($constraint_id)
                );
                $delresult = $ilDB->query($query);
                $query = sprintf("DELETE FROM survey_question_constraint WHERE constraint_fi = %s AND question_fi = %s AND survey_fi = %s",
                        $ilDB->quote($constraint_id),
                        $ilDB->quote($question_id),
                        $ilDB->quote($this->getSurveyId())
                );
                $delresult = $ilDB->query($query);
        }

        function &getSurveyQuestions($with_answers = false)
        {
                global $ilDB;
                $obligatory_states =& $this->getObligatoryStates();
                // get questionblocks
                $all_questions = array();
                $query = sprintf("SELECT survey_questiontype.type_tag, survey_question.question_id, survey_survey_question.heading FROM survey_questiontype, survey_question, survey_survey_question WHERE survey_survey_question.survey_fi = %s AND survey_survey_question.question_fi = survey_question.question_id AND survey_question.questiontype_fi = survey_questiontype.questiontype_id ORDER BY survey_survey_question.sequence",
//              $query = sprintf("SELECT survey_question.question_id, survey_survey_question.heading FROM survey_question, survey_survey_question WHERE survey_survey_question.survey_fi = %s AND survey_survey_question.question_fi = survey_question.question_id ORDER BY survey_survey_question.sequence",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                include_once "./survey/classes/class.SurveyQuestion.php";
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $question =& $this->_instanciateQuestion($row["question_id"]);
                        $questionrow = $question->_getQuestionDataArray($row["question_id"]);
                        foreach ($row as $key => $value)
                        {
                                $questionrow[$key] = $value;
                        }
                        $all_questions[$row["question_id"]] = $questionrow;
                        if (array_key_exists($row["question_id"], $obligatory_states))
                        {
                                $all_questions[$row["question_id"]]["obligatory"] = $obligatory_states[$row["question_id"]];
                        }
                }
                // get all questionblocks
                $questionblocks = array();
                $in = join(array_keys($all_questions), ",");
                if ($in)
                {
                        $query = sprintf("SELECT survey_questionblock.*, survey_questionblock_question.question_fi FROM survey_questionblock, survey_questionblock_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_questionblock_question.survey_fi = %s AND survey_questionblock_question.question_fi IN ($in)",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                        while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                        {
                                $questionblocks[$row->question_fi] = $row;
                        }                       
                }
                
                foreach ($all_questions as $question_id => $row)
                {
                        $constraints = $this->getConstraints($question_id);
                        if (isset($questionblocks[$question_id]))
                        {
                                $all_questions[$question_id]["questionblock_title"] = $questionblocks[$question_id]->title;
                                $all_questions[$question_id]["questionblock_id"] = $questionblocks[$question_id]->questionblock_id;
                                $all_questions[$question_id]["constraints"] = $constraints;
                        }
                        else
                        {
                                $all_questions[$question_id]["questionblock_title"] = "";
                                $all_questions[$question_id]["questionblock_id"] = "";
                                $all_questions[$question_id]["constraints"] = $constraints;
                        }
                        if ($with_answers)
                        {
                                $answers = array();
                                $query = sprintf("SELECT survey_variable.*, survey_category.title FROM survey_variable, survey_category WHERE survey_variable.question_fi = %s AND survey_variable.category_fi = survey_category.category_id ORDER BY sequence ASC",
                                        $ilDB->quote($question_id . "")
                                );
                                $result = $ilDB->query($query);
                                if (strcmp(strtolower(get_class($result)), db_result) == 0) {
                                        while ($data = $result->fetchRow(DB_FETCHMODE_OBJECT)) {
                                                array_push($answers, $data->title);
                                        }
                                }
                                $all_questions[$question_id]["answers"] = $answers;                             
                        }
                }
                return $all_questions;
        }
        
        function &getQuestiontypes()
        {
                global $ilDB;
                $query = "SELECT type_tag FROM survey_questiontype";
                $result = $ilDB->query($query);
                $result_array = array();
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        array_push($result_array, $row->type_tag);
                }
                return $result_array;
        }

        function setObligatoryStates($obligatory_questions)
        {
                global $ilDB;
                $query = sprintf("SELECT * FROM survey_survey_question WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                if (!array_key_exists($row["question_fi"], $obligatory_questions))
                                {
                                        $obligatory_questions[$row["question_fi"]] = 0;
                                }
                        }
                }

          // set the obligatory states in the database
                $query = sprintf("DELETE FROM survey_question_obligatory WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);

          // set the obligatory states in the database
                foreach ($obligatory_questions as $question_fi => $obligatory)
                {
                        $query = sprintf("INSERT INTO survey_question_obligatory (question_obligatory_id, survey_fi, question_fi, obligatory, TIMESTAMP) VALUES (NULL, %s, %s, %s, NULL)",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($question_fi . ""),
                                $ilDB->quote($obligatory . "")
                        );
                        $result = $ilDB->query($query);
                }
        }
        
        function &getObligatoryStates()
        {
                global $ilDB;
                $obligatory_states = array();
                $query = sprintf("SELECT * FROM survey_question_obligatory WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                $obligatory_states[$row["question_fi"]] = $row["obligatory"];
                        }
                }
                return $obligatory_states;
        }
        
        function &getSurveyPages()
        {
                global $ilDB;
                $obligatory_states =& $this->getObligatoryStates();
                // get questionblocks
                $all_questions = array();
                $query = sprintf("SELECT survey_question.*, survey_questiontype.type_tag, survey_survey_question.heading FROM survey_question, survey_questiontype, survey_survey_question WHERE survey_survey_question.survey_fi = %s AND survey_survey_question.question_fi = survey_question.question_id AND survey_question.questiontype_fi = survey_questiontype.questiontype_id ORDER BY survey_survey_question.sequence",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $all_questions[$row["question_id"]] = $row;
                }
                // get all questionblocks
                $questionblocks = array();
                $in = join(array_keys($all_questions), ",");
                if ($in)
                {
                        $query = sprintf("SELECT survey_questionblock.*, survey_questionblock_question.question_fi FROM survey_questionblock, survey_questionblock_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_questionblock_question.survey_fi = %s AND survey_questionblock_question.question_fi IN ($in)",
                                $ilDB->quote($this->getSurveyId())
                        );
                        $result = $ilDB->query($query);
                        while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                        {
                                $questionblocks["$row->question_fi"] = $row;
                        }                       
                }
                
                $all_pages = array();
                $pageindex = -1;
                $currentblock = "";
                foreach ($all_questions as $question_id => $row)
                {
                        if (array_key_exists($question_id, $obligatory_states))
                        {
                                $all_questions["$question_id"]["obligatory"] = $obligatory_states["$question_id"];
                        }
                        $constraints = array();
                        if (isset($questionblocks[$question_id]))
                        {
                                if (!$currentblock or ($currentblock != $questionblocks[$question_id]->questionblock_id))
                                {
                                        $pageindex++;
                                }
                                $all_questions[$question_id]["questionblock_title"] = $questionblocks[$question_id]->title;
                                $all_questions[$question_id]["questionblock_id"] = $questionblocks[$question_id]->questionblock_id;
                                $currentblock = $questionblocks[$question_id]->questionblock_id;
                                $constraints = $this->getConstraints($question_id);
                                $all_questions[$question_id]["constraints"] = $constraints;
                        }
                        else
                        {
                                $pageindex++;
                                $all_questions[$question_id]["questionblock_title"] = "";
                                $all_questions[$question_id]["questionblock_id"] = "";
                                $currentblock = "";
                                $constraints = $this->getConstraints($question_id);
                                $all_questions[$question_id]["constraints"] = $constraints;
                        }
                        if (!isset($all_pages[$pageindex]))
                        {
                                $all_pages[$pageindex] = array();
                        }
                        array_push($all_pages[$pageindex], $all_questions[$question_id]);
                }
                // calculate position percentage for every page
                $max = count($all_pages);
                $counter = 1;
                foreach ($all_pages as $index => $block)
                {
                        foreach ($block as $blockindex => $question)
                        {
                                $all_pages[$index][$blockindex][position] = $counter / $max;
                        }
                        $counter++;
                }
                return $all_pages;
        }
        
        function getNextPage($active_page_question_id, $direction)
        {
                $foundpage = -1;
                $pages =& $this->getSurveyPages();
                if (strcmp($active_page_question_id, "") == 0)
                {
                        return $pages[0];
                }
                
                foreach ($pages as $key => $question_array)
                {
                        foreach ($question_array as $question)
                        {
                                if ($active_page_question_id == $question["question_id"])
                                {
                                        $foundpage = $key;
                                }
                        }
                }
                if ($foundpage == -1)
                {
                        // error: page not found
                }
                else
                {
                        $foundpage += $direction;
                        if ($foundpage < 0)
                        {
                                return 0;
                        }
                        if ($foundpage >= count($pages))
                        {
                                return 1;
                        }
                        return $pages[$foundpage];
                }
        }
                
        function &getAvailableQuestionpools($use_obj_id = false, $could_be_offline = false)
        {
                global $rbacsystem;
                global $ilDB;
                
                $result_array = array();
                $query = "SELECT object_data.*, object_data.obj_id, object_reference.ref_id FROM object_data, object_reference WHERE object_data.obj_id = object_reference.obj_id AND object_data.type = 'spl'";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {               
                        if ($rbacsystem->checkAccess("write", $row->ref_id) && ($this->_hasUntrashedReference($row->obj_id)))
                        {
                                include_once("./survey/classes/class.ilObjSurveyQuestionPool.php");
                                if (ilObjSurveyQuestionPool::_lookupOnline($row->obj_id) || $could_be_offline)
                                {
                                        if ($use_obj_id)
                                        {
                                                $result_array[$row->obj_id] = $row->title;
                                        }
                                        else
                                        {
                                                $result_array[$row->ref_id] = $row->title;
                                        }
                                }
                        }
                }
                return $result_array;
        }
        
        function getConstraints($question_id)
        {
                global $ilDB;
                
                $result_array = array();
                $query = sprintf("SELECT survey_constraint.*, survey_relation.* FROM survey_question_constraint, survey_constraint, survey_relation WHERE survey_constraint.relation_fi = survey_relation.relation_id AND survey_question_constraint.constraint_fi = survey_constraint.constraint_id AND survey_question_constraint.question_fi = %s AND survey_question_constraint.survey_fi = %s",
                        $ilDB->quote($question_id),
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {               
                        array_push($result_array, array("id" => $row->constraint_id, "question" => $row->question_fi, "short" => $row->shortname, "long" => $row->longname, "value" => $row->value));
                }
                return $result_array;
        }

        function _getConstraints($survey_id)
        {
                global $ilDB;
                $result_array = array();
                $query = sprintf("SELECT survey_question_constraint.question_fi as for_question, survey_constraint.*, survey_relation.* FROM survey_question_constraint, survey_constraint, survey_relation WHERE survey_constraint.relation_fi = survey_relation.relation_id AND survey_question_constraint.constraint_fi = survey_constraint.constraint_id AND survey_question_constraint.survey_fi = %s",
                        $ilDB->quote($survey_id . "")
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {               
                        array_push($result_array, array("id" => $row->constraint_id, "for_question" => $row->for_question, "question" => $row->question_fi, "short" => $row->shortname, "long" => $row->longname, "relation_id" => $row->relation_id, "value" => $row->value));
                }
                return $result_array;
        }


        function &getVariables($question_id)
        {
                global $ilDB;
                
                $result_array = array();
                $query = sprintf("SELECT survey_variable.*, survey_category.title FROM survey_variable LEFT JOIN survey_category ON survey_variable.category_fi = survey_category.category_id WHERE survey_variable.question_fi = %s ORDER BY survey_variable.sequence",
                        $ilDB->quote($question_id)
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $result_array[$row->sequence] = $row;
                }
                return $result_array;
        }
        
        function addConstraint($to_question_id, $if_question_id, $relation, $value)
        {
                global $ilDB;
                
                $query = sprintf("INSERT INTO survey_constraint (constraint_id, question_fi, relation_fi, value) VALUES (NULL, %s, %s, %s)",
                        $ilDB->quote($if_question_id),
                        $ilDB->quote($relation),
                        $ilDB->quote($value)
                );
                $result = $ilDB->query($query);
                if ($result == DB_OK) {
                        $constraint_id = $ilDB->getLastInsertId();
                        $query = sprintf("INSERT INTO survey_question_constraint (question_constraint_id, survey_fi, question_fi, constraint_fi) VALUES (NULL, %s, %s, %s)",
                                $ilDB->quote($this->getSurveyId()),
                                $ilDB->quote($to_question_id),
                                $ilDB->quote($constraint_id)
                        );
                        $result = $ilDB->query($query);
                }
        }
        
        function getAllRelations($short_as_key = false)
        {
                global $ilDB;
                
                $result_array = array();
                $query = "SELECT * FROM survey_relation";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        if ($short_as_key)
                        {
                                $result_array[$row->shortname] = array("short" => $row->shortname, "long" => $row->longname, "id" => $row->relation_id);
                        }
                        else
                        {
                                $result_array[$row->relation_id] = array("short" => $row->shortname, "long" => $row->longname);
                        }
                }
                return $result_array;
        }

        function disinviteUser($user_id)
        {
                global $ilDB;
                
                $query = sprintf("DELETE FROM survey_invited_user WHERE survey_fi = %s AND user_fi = %s",
                        $ilDB->quote($this->getSurveyId()),
                        $ilDB->quote($user_id)
                );
                $result = $ilDB->query($query);
                if ($this->getInvitation() == INVITATION_ON)
                {
                        include_once "./classes/class.ilObjUser.php";
                        if (ilObjUser::_lookupLogin($user_id))
                        {
                                $userObj = new ilObjUser($user_id);
                                $userObj->dropDesktopItem($this->getRefId(), "svy");
                        }
                }
        }

        function inviteUser($user_id)
        {
                global $ilDB;
                
                $query = sprintf("SELECT user_fi FROM survey_invited_user WHERE user_fi = %s AND survey_fi = %s",
                        $ilDB->quote($user_id),
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                if ($result->numRows() < 1)
                {
                        $query = sprintf("INSERT INTO survey_invited_user (invited_user_id, survey_fi, user_fi, TIMESTAMP) VALUES (NULL, %s, %s, NULL)",
                                $ilDB->quote($this->getSurveyId()),
                                $ilDB->quote($user_id)
                        );
                        $result = $ilDB->query($query);
                }
                if ($this->getInvitation() == INVITATION_ON)
                {
                        include_once "./classes/class.ilObjUser.php";
                        if (ilObjUser::_lookupLogin($user_id))
                        {
                                $userObj = new ilObjUser($user_id);
                                $userObj->addDesktopItem($this->getRefId(), "svy");
                        }
                }
        }

        function inviteGroup($group_id)
        {
                include_once "./classes/class.ilObjGroup.php";
                $group = new ilObjGroup($group_id);
                $members = $group->getGroupMemberIds();
                foreach ($members as $user_id)
                {
                        $this->inviteUser($user_id);
                        if ($this->getInvitation() == INVITATION_ON)
                        {
                                if (ilObjUser::_lookupLogin($user_id))
                                {
                                        $userObj = new ilObjUser($user_id);
                                        $userObj->addDesktopItem($this->getRefId(), "svy");
                                }
                        }
                }
        }
        
        function inviteRole($role_id)
        {
                global $rbacreview;
                $members = $rbacreview->assignedUsers($role_id);
                foreach ($members as $user_id)
                {
                        $this->inviteUser($user_id);
                        if ($this->getInvitation() == INVITATION_ON)
                        {
                                if (ilObjUser::_lookupLogin($user_id))
                                {
                                        $userObj = new ilObjUser($user_id);
                                        $userObj->addDesktopItem($this->getRefId(), "svy");
                                }
                        }
                }
        }
        
        function &getInvitedUsers()
        {
                global $ilDB;
                
                $result_array = array();
                $query = sprintf("SELECT user_fi FROM survey_invited_user WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        array_push($result_array, $row->user_fi);
                }
                return $result_array;
        }

        function &getInvitedGroups()
        {
                global $ilDB;
                
                $result_array = array();
                $query = sprintf("SELECT group_fi FROM survey_invited_group WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        array_push($result_array, $row->group_fi);
                }
                return $result_array;
        }

        function deleteWorkingData($question_id, $user_id)
        {
                global $ilDB;
                
                $query = "";
                if ($this->getAnonymize())
                {
                        $query = sprintf("DELETE FROM survey_answer WHERE survey_fi = %s AND question_fi = %s AND anonymous_id = %s",
                                $ilDB->quote($this->getSurveyId()),
                                $ilDB->quote($question_id),
                                $ilDB->quote($_SESSION["anonymous_id"])
                        );
                }
                else
                {
                        $query = sprintf("DELETE FROM survey_answer WHERE survey_fi = %s AND question_fi = %s AND user_fi = %s",
                                $ilDB->quote($this->getSurveyId()),
                                $ilDB->quote($question_id),
                                $ilDB->quote($user_id)
                        );
                }
                $result = $ilDB->query($query);
        }
        
        function saveWorkingData($question_id, $user_id, $anonymize_id, $value = "", $text = "")
        {
                global $ilDB;
                if ($this->isSurveyStarted($user_id, $anonymize_id) === false)
                {
                        $this->startSurvey($user_id, $anonymize_id);
                }
                if (strcmp($value, "") == 0)
                {
                        $value = "NULL";
                }
                else
                {
                        $value = $ilDB->quote($value);
                }
                if (strcmp($text, "") == 0)
                {
                        $text = "NULL";
                }
                else
                {
                        $text = $ilDB->quote($text);
                }
                if ($this->getAnonymize())
                {
                        $user_id = 0;
                }
                $query = sprintf("INSERT INTO survey_answer (answer_id, survey_fi, question_fi, user_fi, anonymous_id, value, textanswer, TIMESTAMP) VALUES (NULL, %s, %s, %s, %s, %s, %s, NULL)",
                        $ilDB->quote($this->getSurveyId() . ""),
                        $ilDB->quote($question_id . ""),
                        $ilDB->quote($user_id . ""),
                        $ilDB->quote($anonymize_id),
                        $value,
                        $text
                );
                $result = $ilDB->query($query);
        }
        
        function loadWorkingData($question_id, $user_id)
        {
                global $ilDB;
                $result_array = array();
                $query = "";
                if ($this->getAnonymize())
                {
                        $query = sprintf("SELECT * FROM survey_answer WHERE survey_fi = %s AND question_fi = %s AND anonymous_id = %s",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($question_id. ""),
                                $ilDB->quote($_SESSION["anonymous_id"])
                        );
                }
                else
                {
                        $query = sprintf("SELECT * FROM survey_answer WHERE survey_fi = %s AND question_fi = %s AND user_fi = %s",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($question_id . ""),
                                $ilDB->quote($user_id . "")
                        );
                }
                $result = $ilDB->query($query);
                if ($result->numRows() >= 1)
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                array_push($result_array, $row);
                        }
                        return $result_array;
                }
                else
                {
                        return $result_array;
                }
        }

        function startSurvey($user_id, $anonymous_id)
        {
                global $ilUser;
                global $ilDB;
                
                if ($this->getAnonymize() && (strlen($anonymous_id) == 0)) return;
                
                if (strcmp($user_id, "") == 0)
                {
                        if ($user_id == ANONYMOUS_USER_ID)
                        {
                                $user_id = 0;
                        }
                }
                // only write the entry if there is valid data!
                if (($user_id > 0) || (strlen($anonymous_id) > 0))
                {
                        $query = sprintf("INSERT INTO survey_finished (finished_id, survey_fi, user_fi, anonymous_id, state, TIMESTAMP) VALUES (NULL, %s, %s, %s, %s, NULL)",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($user_id . ""),
                                $ilDB->quote($anonymous_id . ""),
                                $ilDB->quote(0 . "")
                        );
                        $result = $ilDB->query($query);
                }
        }
                        
        function finishSurvey($user_id, $anonymize_id)
        {
                global $ilDB;
                
                if ($this->getAnonymize())
                {
                        $query = sprintf("UPDATE survey_finished SET state = %s, user_fi = %s WHERE survey_fi = %s AND anonymous_id = %s",
                                $ilDB->quote("1"),
                                $ilDB->quote($user_id . ""),
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($anonymize_id . "")
                        );
                }
                else
                {
                        $query = sprintf("UPDATE survey_finished SET state = %s WHERE survey_fi = %s AND user_fi = %s",
                                $ilDB->quote("1"),
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($user_id . "")
                        );
                }
                $result = $ilDB->query($query);
        }
        
        function isSurveyStarted($user_id, $anonymize_id)
        {
                global $ilDB;
                
                if ($this->getAnonymize())
                {
                        if (strlen($anonymize_id) == 0) return FALSE;
                        if (($user_id != ANONYMOUS_USER_ID) && (strlen($anonymize_id) == 0))
                        {
                                $query = sprintf("SELECT state FROM survey_finished WHERE survey_fi = %s AND user_fi = %s",
                                        $ilDB->quote($this->getSurveyId()),
                                        $ilDB->quote($user_id)
                                );
                        }
                        else
                        {
                                $query = sprintf("SELECT state FROM survey_finished WHERE survey_fi = %s AND anonymous_id = %s",
                                        $ilDB->quote($this->getSurveyId()),
                                        $ilDB->quote($anonymize_id)
                                );
                        }
                }
                else
                {
                        $query = sprintf("SELECT state FROM survey_finished WHERE survey_fi = %s AND user_fi = %s",
                                $ilDB->quote($this->getSurveyId()),
                                $ilDB->quote($user_id)
                        );
                }
                $result = $ilDB->query($query);
                if ($result->numRows() == 0)
                {
                        return false;
                }                       
                else
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        return (int)$row["state"];
                }
        }
        
        function getLastActivePage($user_id)
        {
                global $ilDB;
                $query = "";
                if ($this->getAnonymize())
                {
                        $query = sprintf("SELECT question_fi, TIMESTAMP + 0 AS TIMESTAMP14 FROM survey_answer WHERE survey_fi = %s AND anonymous_id = %s ORDER BY TIMESTAMP14 DESC",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($_SESSION["anonymous_id"])
                        );
                }
                else
                {
                        $query = sprintf("SELECT question_fi, TIMESTAMP + 0 AS TIMESTAMP14 FROM survey_answer WHERE survey_fi = %s AND user_fi = %s ORDER BY TIMESTAMP14 DESC",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($user_id . "")
                        );
                }
                $result = $ilDB->query($query);
                if ($result->numRows() == 0)
                {
                        return "";
                }
                else
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        return $row["question_fi"];
                }
        }

        function checkConstraint($constraint_data, $working_data)
        {
                if (count($working_data) == 0)
                {
                        return 0;
                }
                
                if ((count($working_data) == 1) and (strcmp($working_data[0]["value"], "") == 0))
                {
                        return 0;
                }
                
                foreach ($working_data as $data)
                {
                        switch ($constraint_data["short"])
                        {
                                case "<":
                                        if ($data["value"] < $constraint_data["value"])
                                        {
                                                return 1;
                                        }
                                        break;
                                case "<=":
                                        if ($data["value"] <= $constraint_data["value"])
                                        {
                                                return 1;
                                        }
                                        break;
                                case "=":
                                        if ($data["value"] == $constraint_data["value"])
                                        {
                                                return 1;
                                        }
                                        break;
                                case "<>":
                                        if ($data["value"] != $constraint_data["value"])
                                        {
                                                return 1;
                                        }
                                        break;
                                case ">=":
                                        if ($data["value"] >= $constraint_data["value"])
                                        {
                                                return 1;
                                        }
                                        break;
                                case ">":
                                        if ($data["value"] > $constraint_data["value"])
                                        {
                                                return 1;
                                        }
                                        break;
                        }
                }
                return 0;
        }
        
        function _hasDatasets($survey_id)
        {
                global $ilDB;
                
                $query = sprintf("SELECT finished_id FROM survey_finished WHERE survey_fi = %s",
                        $ilDB->quote($survey_id . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        return true;
                }
                else
                {
                        return false;
                }
        }

        function &getEvaluationForAllUsers()
        {
                global $ilDB;
                
                $users = array();
                $query = sprintf("SELECT * FROM survey_finished WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                array_push($users, $row);
                        }
                }
                $evaluation = array();
                $questions =& $this->getSurveyQuestions();
                foreach ($users as $row)
                {
                        if (($row["user_fi"] > 0) && ($row["user_fi"] != ANONYMOUS_USER_ID) && ($this->getAnonymize() == 0))
                        {
                                $evaluation[$row["user_fi"]] = $this->getEvaluationByUser($questions, $row["user_fi"], $row["anonymous_id"]);
                        }
                        else
                        {
                                if (strlen($row["anonymous_id"]) > 0)
                                {
                                        $evaluation[$row["anonymous_id"]] = $this->getEvaluationByUser($questions, $row["user_fi"], $row["anonymous_id"]);
                                }
                        }
                }
                return $evaluation;
        }
        
        function &getEvaluationByUser($questions, $user_id, $anonymous_id = "")
        {
                global $ilDB;
                
                $wherecond = "";
                $wherevalue = "";
                if (strcmp($anonymous_id, "") != 0)
                {
                        $wherecond = "anonymous_id = %s";
                        $wherevalue = $anonymous_id;
                }
                else
                {
                        $wherecond = "user_fi = %s";
                        $wherevalue = $user_id;
                }
                // collect all answers
                $answers = array();
                $query = sprintf("SELECT * FROM survey_answer WHERE $wherecond AND survey_fi = %s",
                        $ilDB->quote($wherevalue),
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        if (!is_array($answers[$row["question_fi"]]))
                        {
                                $answers[$row["question_fi"]] = array();
                        }
                        array_push($answers[$row["question_fi"]], $row);
                }
                $username = $this->lng->txt("anonymous");
                $gender = "";
                if (($user_id > 0) && ($user_id != ANONYMOUS_USER_ID) && ($this->getAnonymize() == 0))
                {
                        include_once "./classes/class.ilObjUser.php";
                        if (strlen(ilObjUser::_lookupLogin($user_id)) == 0)
                        {
                                $username = $this->lng->txt("deleted_user");
                                $gender = "";
                        }
                        else
                        {
                                $user = new ilObjUser($user_id);
                                $username = $user->getFullname();
                                $gender = $user->getGender();
                                if (strlen($gender) == 1) $gender = $this->lng->txt("gender_$gender");
                        }
                }
                $resultset = array(
                        "name" => $username,
                        "gender" => $gender,
                        "answers" => array()
                );
                foreach ($questions as $key => $question)
                {
                        if (array_key_exists($key, $answers))
                        {
                                $resultset["answers"][$key] = $answers[$key];
                        }
                        else
                        {
                                $resultset["answers"][$key] = array();
                        }
                        sort($resultset["answers"][$key]);
                }
                return $resultset;
        }
        
        function getCumulatedResults(&$question)
        {
                global $ilDB;
                
                $query = sprintf("SELECT finished_id FROM survey_finished WHERE survey_fi = %s",
                        $ilDB->quote($this->getSurveyId())
                );
                $result = $ilDB->query($query);
                $nr_of_users = $result->numRows();
                
                $result_array =& $question->getCumulatedResults($this->getSurveyId(), $nr_of_users);
                return $result_array;
        }

        function &getQuestions($question_ids)
        {
                $result_array = array();
                $query = "SELECT survey_question.*, survey_questiontype.type_tag FROM survey_question, survey_questiontype WHERE survey_question.questiontype_fi = survey_questiontype.questiontype_id AND survey_question.question_id IN (" . join($question_ids, ",") . ")";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        array_push($result_array, $row);
                }
                return $result_array;
        }
        
        function &getQuestionblocks($questionblock_ids)
        {
                global $ilDB;
                
                $result_array = array();
    $query = "SELECT survey_questionblock.*, survey_survey.obj_fi, survey_question.title AS questiontitle, survey_survey_question.sequence, object_data.title as surveytitle, survey_question.question_id FROM object_reference, object_data, survey_questionblock, survey_questionblock_question, survey_survey, survey_question, survey_survey_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_survey.survey_id = survey_questionblock_question.survey_fi AND survey_questionblock_question.question_fi = survey_question.question_id AND survey_survey.obj_fi = object_reference.obj_id AND object_reference.obj_id = object_data.obj_id AND survey_survey_question.survey_fi = survey_survey.survey_id AND survey_survey_question.question_fi = survey_question.question_id AND survey_questionblock.questionblock_id IN (" . join($questionblock_ids, ",") . ") ORDER BY survey_survey.survey_id, survey_survey_question.sequence";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        if ($row["questionblock_id"] != $qbid)
                        {
                                $sequence = 1;
                        }
                        $row["sequence"] = $sequence++;
                        $result_array[$row["questionblock_id"]][$row["question_id"]] = $row;
                        $qbid = $row["questionblock_id"];
                }
                return $result_array;
        }

        function &getForbiddenQuestionpools()
        {
                global $rbacsystem;
                global $ilDB;
                
                // get all available questionpools and remove the trashed questionspools
                $forbidden_pools = array();
                $query = "SELECT object_data.*, object_data.obj_id, object_reference.ref_id FROM object_data, object_reference WHERE object_data.obj_id = object_reference.obj_id AND object_data.type = 'spl'";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {               
                        include_once("./survey/classes/class.ilObjSurveyQuestionPool.php");
                        if (!$rbacsystem->checkAccess("write", $row->ref_id) || (!$this->_hasUntrashedReference($row->obj_id)) || (!ilObjSurveyQuestionPool::_lookupOnline($row->obj_id)))
                        {
                                array_push($forbidden_pools, $row->obj_id);
                        }
                }
                return $forbidden_pools;
        }
        
        function getQuestionsTable($sortoptions, $filter_text, $sel_filter_type, $startrow = 0, $completeonly = 0, $filter_question_type = "", $filter_questionpool = "")
        {
                global $ilUser;
                global $ilDB;
                
                $where = "";
                if (strlen($filter_text) > 0) {
                        switch($sel_filter_type) {
                                case "title":
                                        $where = " AND survey_question.title LIKE " . $ilDB->quote("%" . $filter_text . "%");
                                        break;
                                case "description":
                                        $where = " AND survey_question.description LIKE " . $ilDB->quote("%" . $filter_text . "%");
                                        break;
                                case "author":
                                        $where = " AND survey_question.author LIKE " . $ilDB->quote("%" . $filter_text . "%");
                                        break;
                        }
                }
  
                if ($filter_question_type && (strcmp($filter_question_type, "all") != 0))
                {
                        $where .= " AND survey_questiontype.type_tag = " . $ilDB->quote($filter_question_type);
                }
                
                if ($filter_questionpool && (strcmp($filter_questionpool, "all") != 0))
                {
                        $where .= " AND survey_question.obj_fi = $filter_questionpool";
                }
  
    // build sort order for sql query
                $order = "";
                $images = array();
    if (count($sortoptions)) 
                {
                        include_once "./classes/class.ilUtil.php";
      foreach ($sortoptions as $key => $value) 
                        {
        switch($key) 
                                {
          case "title":
            $order = " ORDER BY title $value";
            $images["title"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
          case "description":
            $order = " ORDER BY description $value";
            $images["description"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
          case "type":
            $order = " ORDER BY questiontype_id $value";
            $images["type"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
          case "author":
            $order = " ORDER BY author $value";
            $images["author"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
          case "created":
            $order = " ORDER BY created $value";
            $images["created"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
          case "updated":
            $order = " ORDER BY TIMESTAMP14 $value";
            $images["updated"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
                                        case "qpl":
                                                $order = " ORDER BY obj_fi $value";
            $images["qpl"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
                                                break;
        }
      }
    }
                $maxentries = $ilUser->prefs["hits_per_page"];
                if ($maxentries < 1)
                {
                        $maxentries = 9999;
                }

                $forbidden_pools =& $this->getForbiddenQuestionpools();
                $forbidden = "";
                if (count($forbidden_pools))
                {
                        $forbidden = " AND survey_question.obj_fi NOT IN (" . join($forbidden_pools, ",") . ")";
                }
                if ($completeonly)
                {
                        $forbidden .= " AND survey_question.complete = " . $ilDB->quote("1");
                }
                $existing = "";
                $existing_questions =& $this->getExistingQuestions();
                if (count($existing_questions))
                {
                        $existing = " AND survey_question.question_id NOT IN (" . join($existing_questions, ",") . ")";
                }
          $query = "SELECT survey_question.question_id, survey_question.TIMESTAMP + 0 AS TIMESTAMP14 FROM survey_question, survey_questiontype WHERE survey_question.questiontype_fi = survey_questiontype.questiontype_id$forbidden$existing AND ISNULL(survey_question.original_id) " . " $where$order$limit";
    $query_result = $ilDB->query($query);
                $max = $query_result->numRows();
                if ($startrow > $max -1)
                {
                        $startrow = $max - ($max % $maxentries);
                }
                else if ($startrow < 0)
                {
                        $startrow = 0;
                }
                $limit = " LIMIT $startrow, $maxentries";
          $query = "SELECT survey_question.*, survey_question.TIMESTAMP + 0 AS TIMESTAMP14, survey_questiontype.type_tag, object_reference.ref_id FROM survey_question, survey_questiontype, object_reference WHERE survey_question.questiontype_fi = survey_questiontype.questiontype_id$forbidden$existing AND survey_question.obj_fi = object_reference.obj_id AND ISNULL(survey_question.original_id) " . " $where$order$limit";
    $query_result = $ilDB->query($query);
                $rows = array();
                if ($query_result->numRows())
                {
                        while ($row = $query_result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                array_push($rows, $row);
                        }
                }
                $nextrow = $startrow + $maxentries;
                if ($nextrow > $max - 1)
                {
                        $nextrow = $startrow;
                }
                $prevrow = $startrow - $maxentries;
                if ($prevrow < 0)
                {
                        $prevrow = 0;
                }
                return array(
                        "rows" => $rows,
                        "images" => $images,
                        "startrow" => $startrow,
                        "nextrow" => $nextrow,
                        "prevrow" => $prevrow,
                        "step" => $maxentries,
                        "rowcount" => $max
                );
        }

        function getQuestionblocksTable($sortoptions, $filter_text, $sel_filter_type, $startrow = 0)
        {
                global $ilDB;
                global $ilUser;
                $where = "";
                if (strlen($filter_text) > 0) {
                        switch($sel_filter_type) {
                                case "title":
                                        $where = " AND survey_questionblock.title LIKE " . $ilDB->quote("%" . $filter_text . "%");
                                        break;
                        }
                }
  
    // build sort order for sql query
                $order = "";
                $images = array();
    if (count($sortoptions)) 
                {
                        include_once "./classes/class.ilUtil.php";
      foreach ($sortoptions as $key => $value) 
                        {
        switch($key) 
                                {
          case "title":
                                                $order = " ORDER BY survey_questionblock.title $value";
            $images["title"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
            break;
                                        case "svy":
                                                $order = " ORDER BY survey_survey_question.survey_fi $value";
            $images["svy"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
                                                break;
        }
      }
    }
                $maxentries = $ilUser->prefs["hits_per_page"];
                if ($order)
                {
                        $order .=  ",survey_survey_question.sequence ASC";
                }
                else
                {
                        $order = " ORDER BY survey_survey_question.sequence ASC";
                }
                $query = "SELECT survey_questionblock.questionblock_id FROM object_reference, object_data, survey_questionblock, survey_questionblock_question, survey_survey, survey_question, survey_survey_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_survey.survey_id = survey_questionblock_question.survey_fi AND survey_questionblock_question.question_fi = survey_question.question_id AND survey_survey.obj_fi = object_reference.obj_id AND object_reference.obj_id = object_data.obj_id AND survey_survey_question.survey_fi = survey_survey.survey_id AND survey_survey_question.question_fi = survey_question.question_id$where GROUP BY survey_questionblock.questionblock_id$order$limit";
    $query_result = $ilDB->query($query);
                $questionblock_ids = array();
                if ($query_result->numRows())
                {
                        while ($row = $query_result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                array_push($questionblock_ids, $row["questionblock_id"]);
                        }
                }
                
                $max = $query_result->numRows();
                if ($startrow > $max -1)
                {
                        $startrow = $max - ($max % $maxentries);
                }
                else if ($startrow < 0)
                {
                        $startrow = 0;
                }
                $limit = " LIMIT $startrow, $maxentries";
                $query = "SELECT survey_questionblock.*, object_data.title as surveytitle FROM object_reference, object_data, survey_questionblock, survey_questionblock_question, survey_survey, survey_question, survey_survey_question WHERE survey_questionblock.questionblock_id = survey_questionblock_question.questionblock_fi AND survey_survey.survey_id = survey_questionblock_question.survey_fi AND survey_questionblock_question.question_fi = survey_question.question_id AND survey_survey.obj_fi = object_reference.obj_id AND object_reference.obj_id = object_data.obj_id AND survey_survey_question.survey_fi = survey_survey.survey_id AND survey_survey_question.question_fi = survey_question.question_id$where GROUP BY survey_questionblock.questionblock_id$order$limit";
    $query_result = $ilDB->query($query);
                $rows = array();
                if ($query_result->numRows())
                {
                        while ($row = $query_result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                $questions_array =& $this->getQuestionblockQuestions($row["questionblock_id"]);
                                $counter = 1;
                                foreach ($questions_array as $key => $value)
                                {
                                        $questions_array[$key] = "$counter. $value";
                                        $counter++;
                                }
                                $rows[$row["questionblock_id"]] = array(
                                        "questionblock_id" => $row["questionblock_id"],
                                        "title" => $row["title"], 
                                        "surveytitle" => $row["surveytitle"], 
                                        "questions" => join($questions_array, ", "),
                                        "owner" => $row["owner_fi"]
                                );
                        }
                }
                $nextrow = $startrow + $maxentries;
                if ($nextrow > $max - 1)
                {
                        $nextrow = $startrow;
                }
                $prevrow = $startrow - $maxentries;
                if ($prevrow < 0)
                {
                        $prevrow = 0;
                }
                return array(
                        "rows" => $rows,
                        "images" => $images,
                        "startrow" => $startrow,
                        "nextrow" => $nextrow,
                        "prevrow" => $prevrow,
                        "step" => $maxentries,
                        "rowcount" => $max
                );
        }

        function &_getQuestiontypes()
        {
                global $ilDB;
                
                $questiontypes = array();
                $query = "SELECT * FROM survey_questiontype ORDER BY type_tag";
                $query_result = $ilDB->query($query);
                while ($row = $query_result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        array_push($questiontypes, $row["type_tag"]);
                }
                return $questiontypes;
        }
                
        function to_xml()
        {
                include_once("./classes/class.ilXmlWriter.php");
                $a_xml_writer = new ilXmlWriter;
                // set xml header
                $a_xml_writer->xmlHeader();
                $a_xml_writer->xmlStartTag("questestinterop");
                $attrs = array(
                        "ident" => $this->getSurveyId(),
                        "title" => $this->getTitle()
                );
                $a_xml_writer->xmlStartTag("survey", $attrs);
                
                $a_xml_writer->xmlElement("qticomment", NULL, $this->getDescription());
                $a_xml_writer->xmlElement("qticomment", NULL, "ILIAS Version=".$this->ilias->getSetting("ilias_version"));
                $a_xml_writer->xmlElement("qticomment", NULL, "Author=".$this->getAuthor());
                // add ILIAS specific metadata
                $a_xml_writer->xmlStartTag("objectives");
                $attrs = array(
                        "label" => "introduction"
                );
                $a_xml_writer->xmlStartTag("material", $attrs);
                $a_xml_writer->xmlElement("mattext", NULL, $this->getIntroduction());
                $a_xml_writer->xmlEndTag("material");
                $attrs = array(
                        "label" => "outro"
                );
                $a_xml_writer->xmlStartTag("material", $attrs);
                $a_xml_writer->xmlElement("mattext", NULL, $this->getOutro());
                $a_xml_writer->xmlEndTag("material");
                $a_xml_writer->xmlEndTag("objectives");

                // add the rest of the preferences in qtimetadata tags, because there is no correspondent definition in QTI
                $a_xml_writer->xmlStartTag("qtimetadata");
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "SCORM");
                include_once "./Services/MetaData/classes/class.ilMD.php";
                $md = new ilMD($this->getId(),0, $this->getType());
                $writer = new ilXmlWriter();
                $md->toXml($writer);
                $metadata = $writer->xmlDumpMem();
                $a_xml_writer->xmlElement("fieldentry", NULL, $metadata);
                $a_xml_writer->xmlEndTag("qtimetadatafield");
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "author");
                $a_xml_writer->xmlElement("fieldentry", NULL, $this->getAuthor());
                $a_xml_writer->xmlEndTag("qtimetadatafield");
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "description");
                $a_xml_writer->xmlElement("fieldentry", NULL, $this->getDescription());
                $a_xml_writer->xmlEndTag("qtimetadatafield");
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "evaluation_access");
                $a_xml_writer->xmlElement("fieldentry", NULL, $this->getEvaluationAccess());
                $a_xml_writer->xmlEndTag("qtimetadatafield");
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "anonymize");
                $a_xml_writer->xmlElement("fieldentry", NULL, $this->getAnonymize());
                $a_xml_writer->xmlEndTag("qtimetadatafield");
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "status");
                $a_xml_writer->xmlElement("fieldentry", NULL, $this->getStatus());
                $a_xml_writer->xmlEndTag("qtimetadatafield");
                if ($this->getStartDateEnabled())
                {
                        $a_xml_writer->xmlStartTag("qtimetadatafield");
                        $a_xml_writer->xmlElement("fieldlabel", NULL, "startdate");
                        $a_xml_writer->xmlElement("fieldentry", NULL, sprintf("P%dY%dM%dDT0H0M0S", $this->getStartYear(), $this->getStartMonth(), $this->getStartDay()));
                        $a_xml_writer->xmlEndTag("qtimetadatafield");
                }
                if ($this->getEndDateEnabled())
                {
                        $a_xml_writer->xmlStartTag("qtimetadatafield");
                        $a_xml_writer->xmlElement("fieldlabel", NULL, "enddate");
                        $a_xml_writer->xmlElement("fieldentry", NULL, sprintf("P%dY%dM%dDT0H0M0S", $this->getEndYear(), $this->getEndMonth(), $this->getEndDay()));
                        $a_xml_writer->xmlEndTag("qtimetadatafield");
                }
                $a_xml_writer->xmlStartTag("qtimetadatafield");
                $a_xml_writer->xmlElement("fieldlabel", NULL, "display_question_titles");
                $a_xml_writer->xmlElement("fieldentry", NULL, $this->getShowQuestionTitles());
                $a_xml_writer->xmlEndTag("qtimetadatafield");

                // add questionblock descriptions
                $pages =& $this->getSurveyPages();
                foreach ($pages as $question_array)
                {
                        if (count($question_array) > 1)
                        {
                                $question_ids = array();
                                // found a questionblock
                                foreach ($question_array as $question)
                                {
                                        array_push($question_ids, $question["question_id"]);
                                }
                                $a_xml_writer->xmlStartTag("qtimetadatafield");
                                $a_xml_writer->xmlElement("fieldlabel", NULL, "questionblock_" . $question_array[0]["questionblock_id"]);
                                $a_xml_writer->xmlElement("fieldentry", NULL, "<title>" . $question["questionblock_title"]. "</title><questions>" . join($question_ids, ",") . "</questions>");
                                $a_xml_writer->xmlEndTag("qtimetadatafield");
                        }
                }
                // add constraints
                foreach ($pages as $question_array)
                {
                        foreach ($question_array as $question)
                        {
                                if (count($question["constraints"]))
                                {
                                        // found constraints
                                        foreach ($question["constraints"] as $constraint)
                                        {
                                                $a_xml_writer->xmlStartTag("qtimetadatafield");
                                                $a_xml_writer->xmlElement("fieldlabel", NULL, "constraint_" . $question["question_id"]);
                                                $a_xml_writer->xmlElement("fieldentry", NULL, $constraint["question"] . "," . $constraint["short"] . "," . $constraint["value"]);
                                                $a_xml_writer->xmlEndTag("qtimetadatafield");
                                        }
                                }
                        }
                }
                // add headings
                foreach ($pages as $question_array)
                {
                        foreach ($question_array as $question)
                        {
                                if ($question["heading"])
                                {
                                        $a_xml_writer->xmlStartTag("qtimetadatafield");
                                        $a_xml_writer->xmlElement("fieldlabel", NULL, "heading_" . $question["question_id"]);
                                        $a_xml_writer->xmlElement("fieldentry", NULL, $question["heading"]);
                                        $a_xml_writer->xmlEndTag("qtimetadatafield");
                                }
                        }
                }
                $a_xml_writer->xmlEndTag("qtimetadata");
                $a_xml_writer->xmlEndTag("survey");
                $a_xml_writer->xmlEndTag("questestinterop");
                $xml = $a_xml_writer->xmlDumpMem(FALSE);

                $obligatory_states =& $this->getObligatoryStates();
                foreach ($this->questions as $question_id) 
                {
                        $question =& $this->_instanciateQuestion($question_id);
                        if ($question !== FALSE)
                        {
                                $qti_question = $question->to_xml(false, $obligatory_states[$question_id]);
                                $qti_question = preg_replace("/<questestinterop>/", "", $qti_question);
                                $qti_question = preg_replace("/<\/questestinterop>/", "", $qti_question);
                                $xml = str_replace("</questestinterop>", "$qti_question</questestinterop>", $xml);
                        }
                }
                return $xml;
        }
        
  function &_instanciateQuestion($question_id) 
        {
                if ($question_id < 1) return FALSE;
                include_once "./survey/classes/class.SurveyQuestion.php";
                $question_type = SurveyQuestion::_getQuestionType($question_id);
                if (strlen($question_type) == 0) return FALSE;
                include_once "./survey/classes/class.$question_type.php";
                $question = new $question_type();
                $question->loadFromDb($question_id);
                return $question;
  }

        function importObject($file_info, $survey_questionpool_id)
        {
                // check if file was uploaded
                $source = $file_info["tmp_name"];
                $error = 0;
                if (($source == 'none') || (!$source) || $file_info["error"] > UPLOAD_ERR_OK)
                {
                        $this->ilias->raiseError($this->lng->txt("import_no_file_selected"),$this->ilias->error_obj->MESSAGE);
                        $error = 1;
                }
                // check correct file type
                if (!((strcmp($file_info["type"], "text/xml") == 0) || (strcmp($file_info["type"], "application/xml") == 0)))
                {
                        $this->ilias->raiseError($this->lng->txt("import_wrong_file_type"),$this->ilias->error_obj->MESSAGE);
                        $error = 1;
                }
                if (!$error)
                {
                        // import file as a survey
                        $import_dir = $this->getImportDirectory();
                        $importfile = tempnam($import_dir, "survey_import");
                        //move_uploaded_file($source, $importfile);
                        include_once "./classes/class.ilUtil.php";
                        ilUtil::moveUploadedFile($source, "survey_import", $importfile);
                        $fh = fopen($importfile, "r");
                        if (!$fh)
                        {
                                $this->ilias->raiseError($this->lng->txt("import_error_opening_file"),$this->ilias->error_obj->MESSAGE);
                                $error = 1;
                                return $error;
                        }
                        $xml = fread($fh, filesize($importfile));
                        $result = fclose($fh);

                        // delete import directory
                        ilUtil::delDir($this->getImportDirectory());
        
                        if (!$result)
                        {
                                $this->ilias->raiseError($this->lng->txt("import_error_closing_file"),$this->ilias->error_obj->MESSAGE);
                                $error = 1;
                                return $error;
                        }
                        if (preg_match("/(<survey[^>]*>.*?<\/survey>)/si", $xml, $matches))
                        {
                                // read survey properties
                                $import_results = $this->from_xml($matches[1]);
                                if ($import_results === false)
                                {
                                        $this->ilias->raiseError($this->lng->txt("import_error_survey_no_proper_values"),$this->ilias->error_obj->MESSAGE);
                                        $error = 1;
                                        return $error;
                                }
                        }
                        else
                        {
                                $this->ilias->raiseError($this->lng->txt("import_error_survey_no_properties"),$this->ilias->error_obj->MESSAGE);
                                $error = 1;
                                return $error;
                        }
                        $question_counter = 0;
                        $new_question_ids = array();
                        if (preg_match_all("/(<item[^>]*>.*?<\/item>)/si", $xml, $matches))
                        {
                                foreach ($matches[1] as $index => $item)
                                {
                                        $question = "";
                                        if (preg_match("/<qticomment>Questiontype\=(.*?)<\/qticomment>/is", $item, $questiontype))
                                        {
                                                include_once "./survey/classes/class.SurveyNominalQuestion.php";
                                                include_once "./survey/classes/class.SurveyOrdinalQuestion.php";
                                                include_once "./survey/classes/class.SurveyMetricQuestion.php";
                                                include_once "./survey/classes/class.SurveyTextQuestion.php";
                                                switch ($questiontype[1])
                                                {
                                                        case NOMINAL_QUESTION_IDENTIFIER:
                                                                $question = new SurveyNominalQuestion();
                                                                break;
                                                        case ORDINAL_QUESTION_IDENTIFIER:
                                                                $question = new SurveyOrdinalQuestion();
                                                                break;
                                                        case METRIC_QUESTION_IDENTIFIER:
                                                                $question = new SurveyMetricQuestion();
                                                                break;
                                                        case TEXT_QUESTION_IDENTIFIER:
                                                                $question = new SurveyTextQuestion();
                                                                break;
                                                }
                                                if ($question)
                                                {
                                                        $question->from_xml("<questestinterop>$item</questestinterop>");
                                                        if ($import_results !== false)
                                                        {
                                                                $question->setObjId($survey_questionpool_id);
                                                                $question->saveToDb();
                                                                $question_id = $question->duplicate(true);
                                                                $this->questions[$question_counter++] = $question_id;
                                                                if (preg_match("/<item\s+ident\=\"(\d+)\"/", $item, $matches))
                                                                {
                                                                        $original_question_id = $matches[1];
                                                                        $new_question_ids[$original_question_id] = $question_id;
                                                                }
                                                        }
                                                        else
                                                        {
                                                                $this->ilias->raiseError($this->lng->txt("error_importing_question"), $this->ilias->error_obj->MESSAGE);
                                                        }
                                                }
                                        }
                                }
                        }

                        $this->saveToDb();
                        // add question blocks
                        foreach ($import_results["questionblocks"] as $questionblock)
                        {
                                foreach ($questionblock["questions"] as $key => $value)
                                {
                                        $questionblock["questions"][$key] = $new_question_ids[$value];
                                }
                                $this->createQuestionblock($questionblock["title"], $questionblock["questions"]);
                        }
                        // add constraints
                        $relations = $this->getAllRelations(true);
                        foreach ($import_results["constraints"] as $constraint)
                        {
                                $this->addConstraint($new_question_ids[$constraint["for"]], $new_question_ids[$constraint["question"]], $relations[$constraint["relation"]]["id"], $constraint["value"]);
                        }
                        foreach ($import_results["headings"] as $qid => $heading)
                        {
                                $this->saveHeading($heading, $new_question_ids[$qid]);
                        }
                }
                return $error;
        }

        function from_xml($xml_text)
        {
                $result = false;
                $xml_text = preg_replace("/>\s*?</", "><", $xml_text);
                $domxml = domxml_open_mem($xml_text);
                $constraints = array();
                $headings = array();
                $questionblocks = array();
                if (!empty($domxml))
                {
                        $root = $domxml->document_element();
                        $this->setTitle($root->get_attribute("title"));
                        $item = $root;
                        $itemnodes = $item->child_nodes();
                        foreach ($itemnodes as $index => $node)
                        {
                                switch ($node->node_name())
                                {
                                        case "qticomment":
                                                $comment = $node->get_content();
                                                if (strpos($comment, "ILIAS Version=") !== false)
                                                {
                                                }
                                                elseif (strpos($comment, "Questiontype=") !== false)
                                                {
                                                }
                                                elseif (strpos($comment, "Author=") !== false)
                                                {
                                                        $comment = str_replace("Author=", "", $comment);
                                                        $this->setAuthor($comment);
                                                }
                                                else
                                                {
                                                        $this->setDescription($comment);
                                                }
                                                break;
                                        case "objectives":
                                                $materials = $node->child_nodes();
                                                foreach ($materials as $material)
                                                {
                                                        if (strcmp($material->get_attribute("label"), "introduction") == 0)
                                                        {
                                                                $mattext = $material->first_child();
                                                                $this->setIntroduction($mattext->get_content());
                                                        }
                                                        else if (strcmp($material->get_attribute("label"), "outro") == 0)
                                                        {
                                                                $mattext = $material->first_child();
                                                                $this->setOutro($mattext->get_content());
                                                        }
                                                }
                                                break;
                                        case "qtimetadata":
                                                $metadata_fields = $node->child_nodes();
                                                foreach ($metadata_fields as $index => $metadata_field)
                                                {
                                                        $fieldlabel = $metadata_field->first_child();
                                                        $fieldentry = $fieldlabel->next_sibling();
                                                        switch ($fieldlabel->get_content())
                                                        {
                                                                case "evaluation_access":
                                                                        $this->setEvaluationAccess($fieldentry->get_content());
                                                                        break;
                                                                case "author":
                                                                        $this->setAuthor($fieldentry->get_content());
                                                                        break;
                                                                case "description":
                                                                        $this->setDescription($fieldentry->get_content());
                                                                        break;
                                                                case "anonymize":
                                                                        $this->setAnonymize($fieldentry->get_content());
                                                                        break;
                                                                case "startdate":
                                                                        $iso8601period = $fieldentry->get_content();
                                                                        if (preg_match("/P(\d+)Y(\d+)M(\d+)DT(\d+)H(\d+)M(\d+)S/", $iso8601period, $matches))
                                                                        {
                                                                                $this->setStartDateEnabled(true);
                                                                                $this->setStartDate(sprintf("%04d-%02d-%02d", $matches[1], $matches[2], $matches[3]));
                                                                        }
                                                                        break;
                                                                case "enddate":
                                                                        $iso8601period = $fieldentry->get_content();
                                                                        if (preg_match("/P(\d+)Y(\d+)M(\d+)DT(\d+)H(\d+)M(\d+)S/", $iso8601period, $matches))
                                                                        {
                                                                                $this->setEndDateEnabled(true);
                                                                                $this->setEndDate(sprintf("%04d-%02d-%02d", $matches[1], $matches[2], $matches[3]));
                                                                        }
                                                                        break;
                                                                case "status":
                                                                        $this->setStatus($fieldentry->get_content());
                                                                        break;
                                                                case "display_question_titles":
                                                                        if ($fieldentry->get_content() == QUESTIONTITLES_HIDDEN)
                                                                        {
                                                                                $this->hideQuestionTitles();
                                                                        }
                                                                        else
                                                                        {
                                                                                $this->showQuestionTitles();
                                                                        }
                                                        }
                                                        if (preg_match("/questionblock_\d+/", $fieldlabel->get_content()))
                                                        {
                                                                $qb = $fieldentry->get_content();
                                                                preg_match("/<title>(.*?)<\/title>/", $qb, $matches);
                                                                $qb_title = $matches[1];
                                                                preg_match("/<questions>(.*?)<\/questions>/", $qb, $matches);
                                                                $qb_questions = $matches[1];
                                                                $qb_questions_array = explode(",", $qb_questions);
                                                                array_push($questionblocks, array(
                                                                        "title" => $qb_title,
                                                                        "questions" => $qb_questions_array
                                                                ));
                                                        }
                                                        if (preg_match("/constraint_(\d+)/", $fieldlabel->get_content(), $matches))
                                                        {
                                                                $constraint = $fieldentry->get_content();
                                                                $constraint_array = explode(",", $constraint);
                                                                if (count($constraint_array) == 3)
                                                                {
                                                                        array_push($constraints, array(
                                                                                "for"      => $matches[1], 
                                                                                "question" => $constraint_array[0],
                                                                                "relation" => $constraint_array[1],
                                                                                "value"    => $constraint_array[2]
                                                                        ));
                                                                }
                                                        }
                                                        if (preg_match("/heading_(\d+)/", $fieldlabel->get_content(), $matches))
                                                        {
                                                                $heading = $fieldentry->get_content();
                                                                $headings[$matches[1]] = $heading;
                                                        }
                                                }
                                                break;
                                }
                        }
                        $result["questionblocks"] = $questionblocks;
                        $result["constraints"] = $constraints;
                        $result["headings"] = $headings;
                }
                return $result;
        }

        function &_getAvailableSurveys($use_object_id = false)
        {
                global $rbacsystem;
                global $ilDB;
                
                $result_array = array();
                $query = "SELECT object_data.*, object_data.obj_id, object_reference.ref_id FROM object_data, object_reference WHERE object_data.obj_id = object_reference.obj_id AND object_data.type = 'svy' ORDER BY object_data.title";
                $result = $ilDB->query($query);
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {               
                        include_once "./classes/class.ilObject.php";
                        if ($rbacsystem->checkAccess("write", $row->ref_id) && (ilObject::_hasUntrashedReference($row->obj_id)))
                        {
                                if ($use_object_id)
                                {
                                        $result_array[$row->obj_id] = $row->title;
                                }
                                else
                                {
                                        $result_array[$row->ref_id] = $row->title;
                                }
                        }
                }
                return $result_array;
        }

        function _clone($obj_id)
        {
                global $ilDB;
                
                $original = new ilObjSurvey($obj_id, false);
                $original->loadFromDb();
                
                $newObj = new ilObjSurvey();
                $newObj->setType("svy");
                $newObj->setTitle($original->getTitle());
                $newObj->setDescription($original->getDescription());
                $newObj->create(true);
                $newObj->createReference();
                $newObj->putInTree($_GET["ref_id"]);
                $newObj->setPermissions($_GET["ref_id"]);
//              $newObj->notify("new",$_GET["ref_id"],$_GET["parent_non_rbac_id"],$_GET["ref_id"],$newObj->getRefId());
                
                $newObj->author = $original->getAuthor();
                $newObj->introduction = $original->getIntroduction();
                $newObj->outro = $original->getOutro();
                $newObj->status = $original->getStatus();
                $newObj->evaluation_access = $original->getEvaluationAccess();
                $newObj->start_date = $original->getStartDate();
                $newObj->startdate_enabled = $original->getStartDateEnabled();
                $newObj->end_date = $original->getEndDate();
                $newObj->enddate_enabled = $original->getEndDateEnabled();
                $newObj->invitation = $original->getInvitation();
                $newObj->invitation_mode = $original->getInvitationMode();
                $newObj->anonymize = $original->getAnonymize();

                $question_pointer = array();
                // clone the questions
                include_once "./survey/classes/class.SurveyQuestion.php";
                foreach ($original->questions as $key => $question_id)
                {
                        $question = ilObjSurvey::_instanciateQuestion($question_id);
                        $question->id = -1;
                        $original_id = SurveyQuestion::_getOriginalId($question_id);
                        $question->saveToDb($original_id);
                        $newObj->questions[$key] = $question->getId();
                        $question_pointer[$question_id] = $question->getId();
                }

                $newObj->saveToDb();            

                // clone the questionblocks
                $questionblocks = array();
                $questionblock_questions = array();
                $query = sprintf("SELECT * FROM survey_questionblock_question WHERE survey_fi = %s",
                        $ilDB->quote($original->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows() > 0)
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                array_push($questionblock_questions, $row);
                                $questionblocks[$row["questionblock_fi"]] = $row["questionblock_fi"];
                        }
                }
                // create new questionblocks
                foreach ($questionblocks as $key => $value)
                {
                        $questionblock = ilObjSurvey::_getQuestionblock($key);
                        $questionblock_id = ilObjSurvey::_addQuestionblock($questionblock["title"], $questionblock["owner_fi"]);
                        $questionblocks[$key] = $questionblock_id;
                }
                // create new questionblock questions
                foreach ($questionblock_questions as $key => $value)
                {
                        $clonequery = sprintf("INSERT INTO survey_questionblock_question (questionblock_question_id, survey_fi, questionblock_fi, question_fi) VALUES (NULL, %s, %s, %s)",
                                $ilDB->quote($newObj->getSurveyId() . ""),
                                $ilDB->quote($questionblocks[$value["questionblock_fi"]] . ""),
                                $ilDB->quote($question_pointer[$value["question_fi"]] . "")
                        );
                        $cloneresult = $ilDB->query($clonequery);
                }
                
                // clone the constraints
                $constraints = ilObjSurvey::_getConstraints($original->getSurveyId());
                foreach ($constraints as $key => $constraint)
                {
                        $newObj->addConstraint($question_pointer[$constraint["for_question"]], $question_pointer[$constraint["question"]], $constraint["relation_id"], $constraint["value"]);
                }
                
                // clone the obligatory states
                $query = sprintf("SELECT * FROM survey_question_obligatory WHERE survey_fi = %s",
                        $ilDB->quote($original->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows() > 0)
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                $clonequery = sprintf("INSERT INTO survey_question_obligatory (question_obligatory_id, survey_fi, question_fi, obligatory, TIMESTAMP) VALUES (NULL, %s, %s, %s, NULL)",
                                        $ilDB->quote($newObj->getSurveyId() . ""),
                                        $ilDB->quote($question_pointer[$row["question_fi"]] . ""),
                                        $ilDB->quote($row["obligatory"])
                                );
                                $cloneresult = $ilDB->query($clonequery);
                        }
                }

                // clone meta data
                include_once "./Services/MetaData/classes/class.ilMD.php";
                $md = new ilMD($original->getId(),0,$original->getType());
                $new_md =& $md->cloneMD($newObj->getId(),0,$newObj->getType());
                return $newObj->getRefId();
        }

        function createExportDirectory()
        {
                include_once "./classes/class.ilUtil.php";
                $svy_data_dir = ilUtil::getDataDir()."/svy_data";
                ilUtil::makeDir($svy_data_dir);
                if(!is_writable($svy_data_dir))
                {
                        $this->ilias->raiseError("Survey Data Directory (".$svy_data_dir
                                .") not writeable.",$this->ilias->error_obj->FATAL);
                }
                
                // create learning module directory (data_dir/lm_data/lm_<id>)
                $svy_dir = $svy_data_dir."/svy_".$this->getId();
                ilUtil::makeDir($svy_dir);
                if(!@is_dir($svy_dir))
                {
                        $this->ilias->raiseError("Creation of Survey Directory failed.",$this->ilias->error_obj->FATAL);
                }
                // create Export subdirectory (data_dir/lm_data/lm_<id>/Export)
                $export_dir = $svy_dir."/export";
                ilUtil::makeDir($export_dir);
                if(!@is_dir($export_dir))
                {
                        $this->ilias->raiseError("Creation of Export Directory failed.",$this->ilias->error_obj->FATAL);
                }
        }

        function getExportDirectory()
        {
                include_once "./classes/class.ilUtil.php";
                $export_dir = ilUtil::getDataDir()."/svy_data"."/svy_".$this->getId()."/export";

                return $export_dir;
        }
        
        function getExportFiles($dir)
        {
                // quit if import dir not available
                if (!@is_dir($dir) or
                        !is_writeable($dir))
                {
                        return array();
                }

                // open directory
                $dir = dir($dir);

                // initialize array
                $file = array();

                // get files and save the in the array
                while ($entry = $dir->read())
                {
                        if ($entry != "." and
                                $entry != ".." and
                                substr($entry, -4) == ".xml" and
                                ereg("^[0-9]{10}_{2}[0-9]+_{2}(survey__)*[0-9]+\.xml\$", $entry))
                        {
                                $file[] = $entry;
                        }
                }

                // close import directory
                $dir->close();
                // sort files
                sort ($file);
                reset ($file);

                return $file;
        }

        function createImportDirectory()
        {
                include_once "./classes/class.ilUtil.php";
                $svy_data_dir = ilUtil::getDataDir()."/svy_data";
                ilUtil::makeDir($svy_data_dir);
                
                if(!is_writable($svy_data_dir))
                {
                        $this->ilias->raiseError("Survey Data Directory (".$svy_data_dir
                                .") not writeable.",$this->ilias->error_obj->FATAL);
                }

                // create test directory (data_dir/svy_data/svy_<id>)
                $svy_dir = $svy_data_dir."/svy_".$this->getId();
                ilUtil::makeDir($svy_dir);
                if(!@is_dir($svy_dir))
                {
                        $this->ilias->raiseError("Creation of Survey Directory failed.",$this->ilias->error_obj->FATAL);
                }

                // create import subdirectory (data_dir/svy_data/svy_<id>/import)
                $import_dir = $svy_dir."/import";
                ilUtil::makeDir($import_dir);
                if(!@is_dir($import_dir))
                {
                        $this->ilias->raiseError("Creation of Import Directory failed.",$this->ilias->error_obj->FATAL);
                }
        }

        function getImportDirectory()
        {
                include_once "./classes/class.ilUtil.php";
                $import_dir = ilUtil::getDataDir()."/svy_data".
                        "/svy_".$this->getId()."/import";
                if (!is_dir($import_dir))
                {
                        ilUtil::makeDirParents($import_dir);
                }
                if(@is_dir($import_dir))
                {
                        return $import_dir;
                }
                else
                {
                        return false;
                }
        }
        
        function saveHeading($heading = "", $insertbefore)
        {
                global $ilDB;
                if ($heading)
                {
                        $query = sprintf("UPDATE survey_survey_question SET heading=%s WHERE survey_fi=%s AND question_fi=%s",
                                $ilDB->quote($heading),
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($insertbefore)
                        );
                }
                else
                {
                        $query = sprintf("UPDATE survey_survey_question SET heading=NULL WHERE survey_fi=%s AND question_fi=%s",
                                $ilDB->quote($this->getSurveyId() . ""),
                                $ilDB->quote($insertbefore)
                        );
                }
                $ilDB->query($query);
        }

        function _getRefIdFromObjId($obj_id)
        {
                global $ilDB;
                
                $query = sprintf("SELECT ref_id FROM object_reference WHERE obj_id=%s",
                        $ilDB->quote($obj_id)
                        
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        return $row["ref_id"];
                }
                return 0;
        }
        
        function isAnonymousKey($key)
        {
                global $ilDB;
                
                $query = sprintf("SELECT anonymous_id FROM survey_anonymous WHERE survey_key = %s AND survey_fi = %s",
                        $ilDB->quote($key . ""),
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows() == 1)
                {
                        return true;
                }
                else
                {
                        return false;
                }
        }
        
        function getUserSurveyCode($user_id)
        {
                global $ilDB;
                
                if ($user_id == ANONYMOUS_USER_ID) return "";
                $query = sprintf("SELECT anonymous_id FROM survey_finished WHERE survey_fi = %s AND user_fi = %s",
                        $ilDB->quote($this->getSurveyId() . ""),
                        $ilDB->quote($user_id . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows() == 1)
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        return $row["anonymous_id"];
                }
                else
                {
                        return "";
                }
        }
        
        function isAnonymizedParticipant($key)
        {
                global $ilDB;
                
                $query = sprintf("SELECT finished_id FROM survey_finished WHERE anonymous_id = %s AND survey_fi = %s",
                        $ilDB->quote($key . ""),
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows() == 1)
                {
                        return true;
                }
                else
                {
                        return false;
                }
        }
        
        function checkSurveyCode($code)
        {
                if ($this->isAnonymousKey($code))
                {
                        if ($this->isSurveyStarted("", $code) == 1)
                        {
                                return false;
                        }
                        else
                        {
                                return true;
                        }
                }
                else
                {
                        return false;
                }
        }

        function getSurveyCodesCount()
        {
                global $ilDB;

                $query = sprintf("SELECT anonymous_id FROM survey_anonymous WHERE survey_fi = %s AND ISNULL(user_key)",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                return $result->numRows();
        }
        
        function &getSurveyCodesTableData($lang = "en", $offset = 0, $limit = 10, $sort_by = "counter", $sort_order = "asc")
        {
                global $ilDB;

                include_once "./classes/class.ilFormat.php";
                if (strlen($lang) == 0) $lang = "en";
                if (strlen($offset) == 0) $offset = 0;
                if (strlen($limit) == 0) $limit = 10;
                if (strlen($sort_by) == 0) $sort_by = "counter";
                if (strlen($sort_order) == 0) $sort_order = "asc";
                
                switch ($sort_by)
                {
                        case "counter":
                                $order = "ORDER BY survey_finished.anonymous_id $sort_order";
                                break;
                        case "date":
                                $order = "ORDER BY survey_finished.anonymous_id $sort_order";
                                break;
                        case "used":
                                $order = "ORDER BY survey_finished.anonymous_id $sort_order";
                                break;
                        case "url":
                                $order = "ORDER BY survey_finished.anonymous_id $sort_order";
                                break;
                }
                
                $codes = array();
                $query = sprintf("SELECT survey_anonymous.anonymous_id, survey_anonymous.survey_key, survey_anonymous.survey_fi, survey_anonymous.TIMESTAMP + 0 AS TIMESTAMP14, survey_finished.state FROM survey_anonymous LEFT JOIN survey_finished ON survey_anonymous.survey_key = survey_finished.anonymous_id WHERE survey_anonymous.survey_fi = %s AND ISNULL(survey_anonymous.user_key) $order LIMIT $offset,$limit",
                        $ilDB->quote($this->getSurveyId() . "")
                );
                $result = $ilDB->query($query);
                $counter = $offset+1;
                if ($result->numRows() > 0)
                {
                        while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                $created = ilFormat::formatDate(ilFormat::ftimestamp2dateDB($row["TIMESTAMP14"]), "date");

                                $url = "";
                                
                                $state = "<span class=\"smallred\">" . $this->lng->txt("not_used") . "</span>";
                                if ($this->isSurveyCodeUsed($row["survey_key"]))
                                {
                                        $state = "<span class=\"smallgreen\">" . $this->lng->txt("used") . "</span>";
                                }
                                else
                                {
                                        $addlang = "";
                                        if (strlen($lang))
                                        {
                                                $addlang = "&amp;lang=$lang";
                                        }
                                        $url = "<a href=\"" . ILIAS_HTTP_PATH."/goto.php?cmd=infoScreen&target=svy_".$this->getRefId() . "&amp;client_id=" . CLIENT_ID . "&amp;accesscode=".$row["survey_key"].$addlang . "\">";
                                        $url .= $this->lng->txt("survey_code_url_name");
                                        $url .= "</a>";
                                }
                                array_push($codes, array($counter, $row["survey_key"], $created, $state, $url));
                                $counter++;
                        }
                }
                return $codes;
        }
        
        function isSurveyCodeUsed($code)
        {
                global $ilDB;
                $query = sprintf("SELECT finished_id FROM survey_finished WHERE survey_fi = %s AND anonymous_id = %s",
                        $ilDB->quote($this->getSurveyId() . ""),
                        $ilDB->quote($code)
                );
                $result = $ilDB->query($query);
                if ($result->numRows() > 0)
                {
                        return TRUE;
                }
                else
                {
                        return FALSE;
                }
        }
        
        function createSurveyCodes($nrOfCodes)
        {
                global $ilDB;
                for ($i = 0; $i < $nrOfCodes; $i++)
                {
                        $anonymize_key = $this->createNewAccessCode();
                        $query = sprintf("INSERT INTO survey_anonymous (anonymous_id, survey_key, survey_fi, TIMESTAMP) VALUES (NULL, %s, %s, NULL)",
                                $ilDB->quote($anonymize_key . ""),
                                $ilDB->quote($this->getSurveyId() . "")
                        );
                        $result = $ilDB->query($query);
                }
        }
        
        function getUserAccessCode($user_id)
        {
                global $ilDB;
                $access_code = "";
                $query = sprintf("SELECT survey_key FROM survey_anonymous WHERE survey_fi = %s AND user_key = %s",
                        $ilDB->quote($this->getSurveyId() . ""),
                        $ilDB->quote(md5($user_id))
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        $access_code = $row["survey_key"];
                }
                return $access_code;
        }
        
        function saveUserAccessCode($user_id, $access_code)
        {
                global $ilDB;
                $query = sprintf("INSERT INTO survey_anonymous (survey_key, survey_fi, user_key) VALUES (%s, %s, %s)",
                        $ilDB->quote($access_code . ""),
                        $ilDB->quote($this->getSurveyId() . ""),
                        $ilDB->quote(md5($user_id) . "")
                );
                $result = $ilDB->query($query);
        }
        
        function createNewAccessCode()
        {
                // create a 5 character code
                $codestring = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
                mt_srand();
                $code = "";
                for ($i = 1; $i <=5; $i++)
                {
                        $index = mt_rand(0, strlen($codestring)-1);
                        $code .= substr($codestring, $index, 1);
                }
                // verify it against the database
                while ($this->isSurveyCodeUsed($code))
                {
                        $code = $this->createNewAccessCode();
                }
                return $code;
        }

        function &processCSVRow($row, $quoteAll = FALSE, $separator = ";")
        {
                $resultarray = array();
                foreach ($row as $rowindex => $entry)
                {
                        $surround = FALSE;
                        if ($quoteAll)
                        {
                                $surround = TRUE;
                        }
                        if (strpos($entry, "\"") !== FALSE)
                        {
                                $entry = str_replace("\"", "\"\"", $entry);
                                $surround = TRUE;
                        }
                        if (strpos($entry, $separator) !== FALSE)
                        {
                                $surround = TRUE;
                        }
                        // replace all CR LF with LF (for Excel for Windows compatibility
                        $entry = str_replace(chr(13).chr(10), chr(10), $entry);
                        if ($surround)
                        {
                                $resultarray[$rowindex] = utf8_decode("\"" . $entry . "\"");
                        }
                        else
                        {
                                $resultarray[$rowindex] = utf8_decode($entry);
                        }
                }
                return $resultarray;
        }

        function _getLastAccess($finished_id)
        {
                global $ilDB;
                
                $query = sprintf("SELECT survey_answer.TIMESTAMP+0 AS TIMESTAMP14 FROM survey_answer, survey_finished WHERE (survey_finished.user_fi = survey_answer.user_fi OR survey_finished.anonymous_id = survey_answer.anonymous_id) AND survey_finished.finished_id = %s ORDER BY survey_answer.TIMESTAMP DESC",
                        $ilDB->quote($finished_id . "")
                );
                $result = $ilDB->query($query);
                if ($result->numRows())
                {
                        $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                        return $row["TIMESTAMP14"];
                }
                return "";
        }

        function prepareTextareaOutput($txt_output)
        {
                include_once "./classes/class.ilObjAdvancedEditing.php";
                $result = $txt_output;
                if ($prepare_for_latex_output)
                {
                        $result = ilUtil::insertLatexImages($result, "<span class\=\"latex\">", "<\/span>", URL_TO_LATEX);
                }
                // removed: did not work with magic_quotes_gpc = On
                //$result = ilUtil::stripSlashes($result, true, ilObjAdvancedEditing::_getUsedHTMLTagsAsString("survey"));
                if (!$this->isHTML($result))
                {
                        // if the string does not contain HTML code, replace the newlines with HTML line breaks
                        $result = preg_replace("/[\n]/", "<br />", $result);
                }
                else
                {
                        // patch for problems with the <pre> tags in tinyMCE
                        if (preg_match_all("/(<pre>.*?<\/pre>)/ims", $result, $matches))
                        {
                                foreach ($matches[0] as $found)
                                {
                                        $replacement = "";
                                        if (strpos("\n", $found) === FALSE)
                                        {
                                                $replacement = "\n";
                                        }
                                        $removed = preg_replace("/<br\s*?\/>/ims", $replacement, $found);
                                        $result = str_replace($found, $removed, $result);
                                }
                        }
                }
                $result = str_replace("{", "&#123;", $result);
                $result = str_replace("}", "&#125;", $result);
                $result = str_replace("\\", "&#92;", $result);
                return $result;
        }

        function isHTML($a_text)
        {
                if (preg_match("/<[^>]*?>/", $a_text))
                {
                        return TRUE;
                }
                else
                {
                        return FALSE; 
                }
        }

} // END class.ilObjSurvey
?>