assessment/classes/class.ilObjQuestionPool.php

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

require_once "./classes/class.ilObjectGUI.php";
require_once "./classes/class.ilMetaData.php";
require_once "./assessment/classes/class.assQuestion.php";
require_once "./assessment/classes/class.assClozeTestGUI.php";
require_once "./assessment/classes/class.assImagemapQuestionGUI.php";
require_once "./assessment/classes/class.assJavaAppletGUI.php";
require_once "./assessment/classes/class.assMatchingQuestionGUI.php";
require_once "./assessment/classes/class.assMultipleChoiceGUI.php";
require_once "./assessment/classes/class.assOrderingQuestionGUI.php";

class ilObjQuestionPool extends ilObject
{
        function ilObjQuestionPool($a_id = 0,$a_call_by_reference = true)
        {
                $this->type = "qpl";
                $this->ilObject($a_id,$a_call_by_reference);
                if ($a_id == 0)
                {
                        $new_meta =& new ilMetaData();
                        $this->assignMetaData($new_meta);
                }
        }

        function create($a_upload = false)
        {
                parent::create();
                if (!$a_upload)
                {
                        $this->meta_data->setId($this->getId());
                        $this->meta_data->setType($this->getType());
                        $this->meta_data->setTitle($this->getTitle());
                        $this->meta_data->setDescription($this->getDescription());
                        $this->meta_data->setObject($this);
                        $this->meta_data->create();
                }
        }

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

                // put here object specific stuff

                return true;
        }

        function read($a_force_db = false)
        {
                parent::read($a_force_db);
                $this->meta_data =& new ilMetaData($this->getType(), $this->getId());
        }

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

                //put here your module specific stuff
                $this->deleteQuestionpool();

                return true;
        }

        function deleteQuestionpool()
        {
                $query = sprintf("SELECT question_id FROM qpl_questions WHERE obj_fi = %s AND original_id IS NULL",
                        $this->ilias->db->quote($this->getId()));

                $result = $this->ilias->db->query($query);
                $questions = array();

                while ($row = $result->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        array_push($questions, $row["question_id"]);
                }

                if (count($questions))
                {
                        foreach ($questions as $question_id)
                        {
                                $this->deleteQuestion($question_id);
                        }
                }

                // delete export files
                $qpl_data_dir = ilUtil::getDataDir()."/qpl_data";
                $directory = $qpl_data_dir."/qpl_".$this->getId();
                if (is_dir($directory))
                {
                        $directory = escapeshellarg($directory);
                        exec("rm -rf $directory");
                }
        }

        function initDefaultRoles()
        {
                global $rbacadmin;

                // create a local role folder
                //$rfoldObj = $this->createRoleFolder("Local roles","Role Folder of forum obj_no.".$this->getId());

                // create moderator role and assign role to rolefolder...
                //$roleObj = $rfoldObj->createRole("Moderator","Moderator of forum obj_no.".$this->getId());
                //$roles[] = $roleObj->getId();

                //unset($rfoldObj);
                //unset($roleObj);

                return $roles ? $roles : array();
        }

        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 deleteQuestion($question_id)
        {
                $question = new ASS_Question();
                $question->delete($question_id);
        }

        function getQuestiontype($question_id)
        {
                if ($question_id < 1)
                {
                        return;
                }

                $query = sprintf("SELECT qpl_question_type.type_tag FROM qpl_questions, qpl_question_type WHERE qpl_questions.question_type_fi = qpl_question_type.question_type_id AND qpl_questions.question_id = %s",
                        $this->ilias->db->quote($question_id));

                $result = $this->ilias->db->query($query);
                if ($result->numRows() == 1)
                {
                        $data = $result->fetchRow(DB_FETCHMODE_OBJECT);
                        return $data->type_tag;
                }
                else
                {
                        return;
                }
        }

        /* moved to ASS_Question
        function get_total_answers($question_id)
        {
                $query = sprintf("SELECT question_id FROM qpl_questions WHERE original_id = %s",
                        $this->ilias->db->quote($question_id));

                $result = $this->ilias->db->query($query);

                if ($result->numRows() == 0)
                {
                        return 0;
                }
                $found_id = array();
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        array_push($found_id, $row->question_id);
                }

                $query = sprintf("SELECT * FROM tst_solutions WHERE question_fi IN (%s) GROUP BY CONCAT(user_fi,test_fi)",
                        join($found_id, ","));

                $result = $this->ilias->db->query($query);
                return $result->numRows();
        }*/

        /* moved to ASS_Question
        function get_total_right_answers($question_id)
        {
                $query = sprintf("SELECT question_id FROM qpl_questions WHERE original_id = %s",
                        $this->ilias->db->quote($question_id));

                $result = $this->ilias->db->query($query);
                if ($result->numRows() == 0)
                {
                        return 0;
                }
                $found_id = array();
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        array_push($found_id, $row->question_id);
                }
                $query = sprintf("SELECT * FROM tst_solutions WHERE question_fi IN (%s) GROUP BY CONCAT(user_fi,test_fi)",
                        join($found_id, ","));

                $result = $this->ilias->db->query($query);
                $answers = array();
                while ($row = $result->fetchRow(DB_FETCHMODE_OBJECT))
                {
                $question =& $this->createQuestion("", $row->question_fi);
                        $reached = $question->object->getReachedPoints($row->user_fi, $row->test_fi);
                        $max = $question->object->getMaximumPoints();
                        array_push($answers, array("reached" => $reached, "max" => $max));
                }
                $max = 0.0;
                $reached = 0.0;
                foreach ($answers as $key => $value)
                {
                        $max += $value["max"];
                        $reached += $value["reached"];
                }
                return $reached / $max;
        }*/

        function getDescription()
        {
                return parent::getDescription();
                //return $this->meta_data->getDescription();
        }

        function setDescription($a_description)
        {
                parent::setDescription($a_description);
                $this->meta_data->setDescription($a_description);
        }

        function getTitle()
        {
                return parent::getTitle();
        }

        function setTitle($a_title)
        {
                parent::setTitle($a_title);
                $this->meta_data->setTitle($a_title);
        }

        function assignMetaData(&$a_meta_data)
        {
                $this->meta_data =& $a_meta_data;
        }

        function &getMetaData()
        {
                return $this->meta_data;
        }

        function initMeta()
        {
                if (!is_object($this->meta_data))
                {
                        if ($this->getId())
                        {
                                $new_meta =& new ilMetaData($this->getType(), $this->getId());
                        }       
                        else
                        {
                                $new_meta =& new ilMetaData();
                        }
                        $this->assignMetaData($new_meta);
                }
        }

        function updateMetaData()
        {
                $this->initMeta();
                $this->meta_data->update();
                if ($this->meta_data->section != "General")
                {
                        $meta = $this->meta_data->getElement("Title", "General");
                        $this->meta_data->setTitle($meta[0]["value"]);
                        $meta = $this->meta_data->getElement("Description", "General");
                        $this->meta_data->setDescription($meta[0]["value"]);
                }
                else
                {
                        $this->setTitle($this->meta_data->getTitle());
                        $this->setDescription($this->meta_data->getDescription());
                }
                parent::update();
        }


        function isInUse($question_id)
        {
                $query = sprintf("SELECT COUNT(solution_id) AS solution_count FROM tst_solutions WHERE question_fi = %s",
                        $this->ilias->db->quote("$question_id"));

                $result = $this->ilias->db->query($query);
                $row = $result->fetchRow(DB_FETCHMODE_OBJECT);

                return $row->solution_count;
        }

        function &createQuestion($question_type, $question_id = -1)
        {
                if ((!$question_type) and ($question_id > 0))
                {
                        $question_type = $this->getQuestiontype($question_id);
                }

                switch ($question_type)
                {
                        case "qt_multiple_choice_sr":
                                $question =& new ASS_MultipleChoiceGUI();
                                $question->object->set_response(RESPONSE_SINGLE);
                                break;

                        case "qt_multiple_choice_mr":
                                $question =& new ASS_MultipleChoiceGUI();
                                $question->object->set_response(RESPONSE_MULTIPLE);
                                break;

                        case "qt_cloze":
                                $question =& new ASS_ClozeTestGUI();
                                break;

                        case "qt_matching":
                                $question =& new ASS_MatchingQuestionGUI();
                                break;

                        case "qt_ordering":
                                $question =& new ASS_OrderingQuestionGUI();
                                break;

                        case "qt_imagemap":
                                $question =& new ASS_ImagemapQuestionGUI();
                                break;

                        case "qt_javaapplet":
                                $question =& new ASS_JavaAppletGUI();
                                break;

                        case "qt_text":
                                $question =& new ASS_TextQuestionGUI();
                                break;
                }

                if ($question_id > 0)
                {
                        $question->object->loadFromDb($question_id);
                }

                return $question;
        }

        function duplicateQuestion($question_id)
        {
                global $ilUser;

                $question =& $this->createQuestion("", $question_id);
                $counter = 2;
                while ($question->object->questionTitleExists($question->object->getTitle() . " ($counter)"))
                {
                        $counter++;
                }

                $question->object->duplicate(false, $question->object->getTitle() . " ($counter)", $ilUser->fullname, $ilUser->id);
        }

        function getQuestionsTable($sortoptions, $filter_text, $sel_filter_type, $startrow = 0)
        {
                global $ilUser;
                $where = "";
                if (strlen($filter_text) > 0)
                {
                        switch($sel_filter_type)
                        {
                                case "title":
                                        $where = " AND qpl_questions.title LIKE " . $this->ilias->db->quote("%" . $filter_text . "%");
                                        break;

                                case "comment":
                                        $where = " AND qpl_questions.comment LIKE " . $this->ilias->db->quote("%" . $filter_text . "%");
                                        break;

                                case "author":
                                        $where = " AND qpl_questions.author LIKE " . $this->ilias->db->quote("%" . $filter_text . "%");
                                        break;
                        }
                }

            // build sort order for sql query
                $order = "";
                $images = array();
                if (count($sortoptions))
                {
                        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 "comment":
                                                $order = " ORDER BY comment $value";
                                                $images["comment"] = " <img src=\"" . ilUtil::getImagePath(strtolower($value) . "_order.png", true) . "\" alt=\"" . strtolower($value) . "ending order\" />";
                                                break;
                                        case "type":
                                                $order = " ORDER BY question_type_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;
                                }
                        }
                }
                $maxentries = $ilUser->prefs["hits_per_page"];
                if ($maxentries < 1)
                {
                        $maxentries = 9999;
                }
                $query = "SELECT qpl_questions.question_id, qpl_questions.TIMESTAMP + 0 AS TIMESTAMP14 FROM qpl_questions, qpl_question_type WHERE ISNULL(qpl_questions.original_id) AND qpl_questions.question_type_fi = qpl_question_type.question_type_id AND qpl_questions.obj_fi = " . $this->getId() . " $where$order$limit";
                $query_result = $this->ilias->db->query($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 qpl_questions.*, qpl_questions.TIMESTAMP + 0 AS TIMESTAMP14, qpl_question_type.type_tag FROM qpl_questions, qpl_question_type WHERE ISNULL(qpl_questions.original_id) AND qpl_questions.question_type_fi = qpl_question_type.question_type_id AND qpl_questions.obj_fi = " . $this->getId() . " $where$order$limit";
                $query_result = $this->ilias->db->query($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 exportPagesXML(&$a_xml_writer, $a_inst, $a_target_dir, &$expLog, $questions)
        {
                global $ilBench;
                
                $this->mob_ids = array();
                $this->file_ids = array();

                $attrs = array();
                $attrs["Type"] = "Questionpool_Test";
                $a_xml_writer->xmlStartTag("ContentObject", $attrs);

                // MetaData
                $this->exportXMLMetaData($a_xml_writer);

                // PageObjects
                $expLog->write(date("[y-m-d H:i:s] ")."Start Export Page Objects");
                $ilBench->start("ContentObjectExport", "exportPageObjects");
                $this->exportXMLPageObjects($a_xml_writer, $a_inst, $expLog, $questions);
                $ilBench->stop("ContentObjectExport", "exportPageObjects");
                $expLog->write(date("[y-m-d H:i:s] ")."Finished Export Page Objects");

                // MediaObjects
                $expLog->write(date("[y-m-d H:i:s] ")."Start Export Media Objects");
                $ilBench->start("ContentObjectExport", "exportMediaObjects");
                $this->exportXMLMediaObjects($a_xml_writer, $a_inst, $a_target_dir, $expLog);
                $ilBench->stop("ContentObjectExport", "exportMediaObjects");
                $expLog->write(date("[y-m-d H:i:s] ")."Finished Export Media Objects");

                // FileItems
                $expLog->write(date("[y-m-d H:i:s] ")."Start Export File Items");
                $ilBench->start("ContentObjectExport", "exportFileItems");
                $this->exportFileItems($a_target_dir, $expLog);
                $ilBench->stop("ContentObjectExport", "exportFileItems");
                $expLog->write(date("[y-m-d H:i:s] ")."Finished Export File Items");

                $a_xml_writer->xmlEndTag("ContentObject");
        }

        function exportXMLMetaData(&$a_xml_writer)
        {
                $nested = new ilNestedSetXML();
                $nested->setParameterModifier($this, "modifyExportIdentifier");
                $a_xml_writer->appendXML($nested->export($this->getId(),
                        $this->getType()));
        }

        function modifyExportIdentifier($a_tag, $a_param, $a_value)
        {
                if ($a_tag == "Identifier" && $a_param == "Entry")
                {
                        $a_value = ilUtil::insertInstIntoID($a_value);
                }

                return $a_value;
        }


        function exportXMLPageObjects(&$a_xml_writer, $a_inst, &$expLog, $questions)
        {
                global $ilBench;

                include_once "./content/classes/class.ilLMPageObject.php";

                foreach ($questions as $question_id)
                {
                        $ilBench->start("ContentObjectExport", "exportPageObject");
                        $expLog->write(date("[y-m-d H:i:s] ")."Page Object ".$question_id);

                        $attrs = array();
                        $a_xml_writer->xmlStartTag("PageObject", $attrs);

                        
                        // export xml to writer object
                        $ilBench->start("ContentObjectExport", "exportPageObject_XML");
                        $page_object = new ilPageObject("qpl", $question_id);
                        $page_object->buildDom();
                        $page_object->insertInstIntoIDs($a_inst);
                        $mob_ids = $page_object->collectMediaObjects(false);
                        $file_ids = $page_object->collectFileItems();
                        $xml = $page_object->getXMLFromDom(false, false, false, "", true);
                        $xml = str_replace("&","&amp;", $xml);
                        $a_xml_writer->appendXML($xml);
                        $page_object->freeDom();
                        unset ($page_object);
                        
                        $ilBench->stop("ContentObjectExport", "exportPageObject_XML");

                        // collect media objects
                        $ilBench->start("ContentObjectExport", "exportPageObject_CollectMedia");
                        //$mob_ids = $page_obj->getMediaObjectIDs();
                        foreach($mob_ids as $mob_id)
                        {
                                $this->mob_ids[$mob_id] = $mob_id;
                        }
                        $ilBench->stop("ContentObjectExport", "exportPageObject_CollectMedia");

                        // collect all file items
                        $ilBench->start("ContentObjectExport", "exportPageObject_CollectFileItems");
                        //$file_ids = $page_obj->getFileItemIds();
                        foreach($file_ids as $file_id)
                        {
                                $this->file_ids[$file_id] = $file_id;
                        }
                        $ilBench->stop("ContentObjectExport", "exportPageObject_CollectFileItems");
                        
                        $a_xml_writer->xmlEndTag("PageObject");
                        //unset($page_obj);

                        $ilBench->stop("ContentObjectExport", "exportPageObject");
                        

                }
        }

        function exportXMLMediaObjects(&$a_xml_writer, $a_inst, $a_target_dir, &$expLog)
        {
                include_once("content/classes/Media/class.ilObjMediaObject.php");

                foreach ($this->mob_ids as $mob_id)
                {
                        $expLog->write(date("[y-m-d H:i:s] ")."Media Object ".$mob_id);
                        $media_obj = new ilObjMediaObject($mob_id);
                        $media_obj->exportXML($a_xml_writer, $a_inst);
                        $media_obj->exportFiles($a_target_dir);
                        unset($media_obj);
                }
        }

        function exportFileItems($a_target_dir, &$expLog)
        {
                include_once("classes/class.ilObjFile.php");

                foreach ($this->file_ids as $file_id)
                {
                        $expLog->write(date("[y-m-d H:i:s] ")."File Item ".$file_id);
                        $file_obj = new ilObjFile($file_id, false);
                        $file_obj->export($a_target_dir);
                        unset($file_obj);
                }
        }       

        function createExportDirectory()
        {
                $qpl_data_dir = ilUtil::getDataDir()."/qpl_data";
                ilUtil::makeDir($qpl_data_dir);
                if(!is_writable($qpl_data_dir))
                {
                        $this->ilias->raiseError("Questionpool Data Directory (".$qpl_data_dir
                                .") not writeable.",$this->ilias->error_obj->FATAL);
                }
                
                // create learning module directory (data_dir/lm_data/lm_<id>)
                $qpl_dir = $qpl_data_dir."/qpl_".$this->getId();
                ilUtil::makeDir($qpl_dir);
                if(!@is_dir($qpl_dir))
                {
                        $this->ilias->raiseError("Creation of Questionpool Directory failed.",$this->ilias->error_obj->FATAL);
                }
                // create Export subdirectory (data_dir/lm_data/lm_<id>/Export)
                $export_dir = $qpl_dir."/export";
                ilUtil::makeDir($export_dir);
                if(!@is_dir($export_dir))
                {
                        $this->ilias->raiseError("Creation of Export Directory failed.",$this->ilias->error_obj->FATAL);
                }
        }

        function getExportDirectory()
        {
                $export_dir = ilUtil::getDataDir()."/qpl_data"."/qpl_".$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) == ".zip" and
                                ereg("^[0-9]{10}_{2}[0-9]+_{2}(qpl__)*[0-9]+\.zip\$", $entry))
                        {
                                $file[] = $entry;
                        }
                }

                // close import directory
                $dir->close();

                // sort files
                sort ($file);
                reset ($file);
                return $file;
        }

        function createImportDirectory()
        {
                $qpl_data_dir = ilUtil::getDataDir()."/qpl_data";
                ilUtil::makeDir($qpl_data_dir);
                
                if(!is_writable($qpl_data_dir))
                {
                        $this->ilias->raiseError("Questionpool Data Directory (".$qpl_data_dir
                                .") not writeable.",$this->ilias->error_obj->FATAL);
                }

                // create questionpool directory (data_dir/qpl_data/qpl_<id>)
                $qpl_dir = $qpl_data_dir."/qpl_".$this->getId();
                ilUtil::makeDir($qpl_dir);
                if(!@is_dir($qpl_dir))
                {
                        $this->ilias->raiseError("Creation of Questionpool Directory failed.",$this->ilias->error_obj->FATAL);
                }

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

        function getImportDirectory()
        {
                $import_dir = ilUtil::getDataDir()."/qpl_data".
                        "/qpl_".$this->getId()."/import";
                if(@is_dir($import_dir))
                {
                        return $import_dir;
                }
                else
                {
                        return false;
                }
        }
        
        function &getAllQuestionIds()
        {
                $query = sprintf("SELECT question_id FROM qpl_questions WHERE ISNULL(original_id) AND obj_fi = %s",
                        $this->ilias->db->quote($this->getId())
                );
                $query_result = $this->ilias->db->query($query);
                $questions = array();
                if ($query_result->numRows())
                {
                        while ($row = $query_result->fetchRow(DB_FETCHMODE_ASSOC))
                        {
                                array_push($questions, $row["question_id"]);
                        }
                }
                return $questions;
        }
        
        function getImportMapping()
        {
                if (!is_array($this->import_mapping))
                {
                        return array();
                }
                else
                {
                        return $this->import_mapping;
                }
        }
        
        function to_xml($questions)
        {
                $xml = "";
                // export button was pressed
                if (count($questions) > 0)
                {
                        foreach ($questions as $key => $value)
                        {
                                $question =& $this->createQuestion("", $value);
                                $xml .= $question->object->to_xml();
                        }
                        if (count($questions) > 1)
                        {
                                $xml = preg_replace("/<\/questestinterop>\s*<.xml.*?>\s*<questestinterop>/", "", $xml);
                        }
                }
                return $xml;
        }
        
        function importObject($source)
        {
                $this->import_mapping = array();
                if (is_file($source))
                {
                        // import file into questionpool
                        $fh = fopen($source, "r") or die("");
                        $xml = fread($fh, filesize($source));
                        fclose($fh) or die("");
                        if (preg_match_all("/(<item[^>]*>.*?<\/item>)/si", $xml, $matches))
                        {
                                foreach ($matches[1] as $index => $item)
                                {
                                        // get identifier
                                        if (preg_match("/(<item[^>]*>)/is", $item, $start_tag))
                                        {
                                                if (preg_match("/(ident=\"([^\"]*)\")/is", $start_tag[1], $ident))
                                                {
                                                        $ident = $ident[2];
                                                }
                                        }
                                        $question = "";
                                        $qt = "";
                                        if (preg_match("/<fieldlabel>QUESTIONTYPE<\/fieldlabel>\s*<fieldentry>(.*?)<\/fieldentry>/is", $item, $questiontype))
                                        {
                                                $qt = $questiontype[1];
                                        }
                                        if (preg_match("/<qticomment>Questiontype\=(.*?)<\/qticomment>/is", $item, $questiontype))
                                        {
                                                $qt = $questiontype[1];
                                        }
                                        if (strlen($qt))
                                        {
                                                switch ($qt)
                                                {
                                                        case CLOZE_TEST_IDENTIFIER:
                                                                $question = new ASS_ClozeTest();
                                                                break;
                                                        case IMAGEMAP_QUESTION_IDENTIFIER:
                                                                $question = new ASS_ImagemapQuestion();
                                                                break;
                                                        case MATCHING_QUESTION_IDENTIFIER:
                                                                $question = new ASS_MatchingQuestion();
                                                                break;
                                                        case MULTIPLE_CHOICE_QUESTION_IDENTIFIER:
                                                                $question = new ASS_MultipleChoice();
                                                                break;
                                                        case ORDERING_QUESTION_IDENTIFIER:
                                                                $question = new ASS_OrderingQuestion();
                                                                break;
                                                        case JAVAAPPLET_QUESTION_IDENTIFIER:
                                                                $question = new ASS_JavaApplet();
                                                                break;
                                                        case TEXT_QUESTION_IDENTIFIER:
                                                                $question = new ASS_TextQuestion();
                                                                break;
                                                }
                                                if ($question)
                                                {
                                                        $question->setObjId($this->getId());
                                                        if ($question->from_xml("<questestinterop>$item</questestinterop>"))
                                                        {
                                                                $question->saveToDb();
                                                                $this->import_mapping[$ident] = array(
                                                                        "pool" => $question->getId(), "test" => 0);
                                                        }
                                                        else
                                                        {
                                                                $this->ilias->raiseError($this->lng->txt("error_importing_question"), $this->ilias->error_obj->MESSAGE);
                                                        }
                                                }
                                        }
                                }
                        }
                }
        }
        
        function _getQuestionCount($questionpool_id, $complete_questions_only = FALSE)
        {
                global $ilDB;
                $query = sprintf("SELECT COUNT(question_id) AS question_count FROM qpl_questions WHERE obj_fi = %s AND ISNULL(original_id)",
                        $ilDB->quote($questionpool_id . "")
                );
                if ($complete_questions_only)
                {
                        $query .= " AND complete = '1'";
                }
                $result = $ilDB->query($query);
                $row = $result->fetchRow(DB_FETCHMODE_ASSOC);
                return $row["question_count"];
        }
        
} // END class.ilObjQuestionPool
?>