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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Question type class for the randomsamatch question type.
  19   *
  20   * @package    qtype_randomsamatch
  21   * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  
  26  defined('MOODLE_INTERNAL') || die();
  27  
  28  require_once($CFG->dirroot . '/question/type/questionbase.php');
  29  require_once($CFG->dirroot . '/question/type/numerical/question.php');
  30  
  31  /**
  32   * The randomsamatch question type class.
  33   *
  34   * TODO: Make sure short answer questions chosen by a randomsamatch question
  35   * can not also be used by a random question
  36   *
  37   * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  38   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  39   */
  40  class qtype_randomsamatch extends question_type {
  41      /**
  42       * Cache of available shortanswer question ids from a particular category.
  43       * @var array two-dimensional array. The first key is a category id, the
  44       * second key is wether subcategories should be included.
  45       */
  46      private $availablesaquestionsbycategory = array();
  47      const MAX_SUBQUESTIONS = 10;
  48  
  49      public function is_usable_by_random() {
  50          return false;
  51      }
  52  
  53      public function get_question_options($question) {
  54          global $DB;
  55          parent::get_question_options($question);
  56          $question->options = $DB->get_record('qtype_randomsamatch_options',
  57                  array('questionid' => $question->id));
  58  
  59          return true;
  60  
  61      }
  62  
  63      public function save_question_options($question) {
  64          global $DB;
  65  
  66          if (2 > $question->choose) {
  67              $result = new stdClass();
  68              $result->error = "At least two shortanswer questions need to be chosen!";
  69              return $result;
  70          }
  71  
  72          $context = $question->context;
  73  
  74          // Save the question options.
  75          $options = $DB->get_record('qtype_randomsamatch_options', array('questionid' => $question->id));
  76          if (!$options) {
  77              $options = new stdClass();
  78              $options->questionid = $question->id;
  79              $options->correctfeedback = '';
  80              $options->partiallycorrectfeedback = '';
  81              $options->incorrectfeedback = '';
  82              $options->id = $DB->insert_record('qtype_randomsamatch_options', $options);
  83          }
  84  
  85          $options->choose = $question->choose;
  86          $options->subcats = $question->subcats;
  87          $options = $this->save_combined_feedback_helper($options, $question, $context, true);
  88          $DB->update_record('qtype_randomsamatch_options', $options);
  89  
  90          $this->save_hints($question, true);
  91  
  92          return true;
  93      }
  94  
  95      protected function make_hint($hint) {
  96          return question_hint_with_parts::load_from_record($hint);
  97      }
  98  
  99      public function delete_question($questionid, $contextid) {
 100          global $DB;
 101          $DB->delete_records('qtype_randomsamatch_options', array('questionid' => $questionid));
 102  
 103          parent::delete_question($questionid, $contextid);
 104      }
 105  
 106      public function move_files($questionid, $oldcontextid, $newcontextid) {
 107          parent::move_files($questionid, $oldcontextid, $newcontextid);
 108  
 109          $this->move_files_in_combined_feedback($questionid, $oldcontextid, $newcontextid);
 110          $this->move_files_in_hints($questionid, $oldcontextid, $newcontextid);
 111      }
 112  
 113      protected function delete_files($questionid, $contextid) {
 114          parent::delete_files($questionid, $contextid);
 115  
 116          $this->delete_files_in_combined_feedback($questionid, $contextid);
 117          $this->delete_files_in_hints($questionid, $contextid);
 118      }
 119  
 120      protected function initialise_question_instance(question_definition $question, $questiondata) {
 121          parent::initialise_question_instance($question, $questiondata);
 122          $availablesaquestions = $this->get_available_saquestions_from_category(
 123                  $question->category, $questiondata->options->subcats);
 124          $question->shufflestems = false;
 125          $question->stems = array();
 126          $question->choices = array();
 127          $question->right = array();
 128          $this->initialise_combined_feedback($question, $questiondata);
 129          $question->questionsloader = new qtype_randomsamatch_question_loader(
 130                  $availablesaquestions, $questiondata->options->choose);
 131      }
 132  
 133      public function can_analyse_responses() {
 134          return false;
 135      }
 136  
 137      /**
 138       * Get all the usable shortanswer questions from a particular question category.
 139       *
 140       * @param integer $categoryid the id of a question category.
 141       * @param bool $subcategories whether to include questions from subcategories.
 142       * @return array of question records.
 143       */
 144      public function get_available_saquestions_from_category($categoryid, $subcategories) {
 145          if (isset($this->availablesaquestionsbycategory[$categoryid][$subcategories])) {
 146              return $this->availablesaquestionsbycategory[$categoryid][$subcategories];
 147          }
 148  
 149          if ($subcategories) {
 150              $categoryids = question_categorylist($categoryid);
 151          } else {
 152              $categoryids = array($categoryid);
 153          }
 154  
 155          $questionids = question_bank::get_finder()->get_questions_from_categories(
 156                  $categoryids, "qtype = 'shortanswer'");
 157          $this->availablesaquestionsbycategory[$categoryid][$subcategories] = $questionids;
 158          return $questionids;
 159      }
 160  
 161      /**
 162       * @param object $question
 163       * @return mixed either a integer score out of 1 that the average random
 164       * guess by a student might give or an empty string which means will not
 165       * calculate.
 166       */
 167      public function get_random_guess_score($question) {
 168          return 1/$question->options->choose;
 169      }
 170  
 171      /**
 172       * Defines the table which extends the question table. This allows the base questiontype
 173       * to automatically save, backup and restore the extra fields.
 174       *
 175       * @return an array with the table name (first) and then the column names (apart from id and questionid)
 176       */
 177      public function extra_question_fields() {
 178          return array('qtype_randomsamatch_options',
 179                       'choose',        // Number of shortanswer questions to choose.
 180                       'subcats',       // Questions can be choosen from subcategories.
 181                       );
 182      }
 183  
 184      /**
 185       * Imports the question from Moodle XML format.
 186       *
 187       * @param array $xml structure containing the XML data
 188       * @param object $fromform question object to fill: ignored by this function (assumed to be null)
 189       * @param qformat_xml $format format class exporting the question
 190       * @param object $extra extra information (not required for importing this question in this format)
 191       * @return object question object
 192       */
 193      public function import_from_xml($xml, $fromform, qformat_xml $format, $extra=null) {
 194          // Return if data type is not our own one.
 195          if (!isset($xml['@']['type']) || $xml['@']['type'] != $this->name()) {
 196              return false;
 197          }
 198  
 199          // Import the common question headers and set the corresponding field.
 200          $fromform = $format->import_headers($xml);
 201          $fromform->qtype = $this->name();
 202          $format->import_combined_feedback($fromform, $xml, true);
 203          $format->import_hints($fromform, $xml, true);
 204  
 205          $extras = $this->extra_question_fields();
 206          array_shift($extras);
 207          foreach ($extras as $extra) {
 208              $fromform->$extra = $format->getpath($xml, array('#', $extra, 0, '#'), '', true);
 209          }
 210  
 211          return $fromform;
 212      }
 213  
 214      /**
 215       * Exports the question to Moodle XML format.
 216       *
 217       * @param object $question question to be exported into XML format
 218       * @param qformat_xml $format format class exporting the question
 219       * @param object $extra extra information (not required for exporting this question in this format)
 220       * @return string containing the question data in XML format
 221       */
 222      public function export_to_xml($question, qformat_xml $format, $extra=null) {
 223          $expout = '';
 224          $expout .= $format->write_combined_feedback($question->options,
 225                                                      $question->id,
 226                                                      $question->contextid);
 227          $extraquestionfields = $this->extra_question_fields();
 228          array_shift($extraquestionfields);
 229          foreach ($extraquestionfields as $extra) {
 230              $expout .= "    <{$extra}>" . $question->options->$extra . "</{$extra}>\n";
 231          }
 232          return $expout;
 233      }
 234  }