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See Release Notes

  • Bug fixes for general core bugs in 3.10.x will end 8 November 2021 (12 months).
  • Bug fixes for security issues in 3.10.x will end 9 May 2022 (18 months).
  • PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * The default questiontype class.
 *
 * @package    moodlecore
 * @subpackage questiontypes
 * @copyright  1999 onwards Martin Dougiamas {@link http://moodle.com}
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */


defined('MOODLE_INTERNAL') || die();

require_once($CFG->dirroot . '/question/engine/lib.php');
> require_once($CFG->libdir . '/questionlib.php');
/** * This is the base class for Moodle question types. * * There are detailed comments on each method, explaining what the method is * for, and the circumstances under which you might need to override it. * * Note: the questiontype API should NOT be considered stable yet. Very few * question types have been produced yet, so we do not yet know all the places * where the current API is insufficient. I would rather learn from the * experiences of the first few question type implementors, and improve the * interface to meet their needs, rather the freeze the API prematurely and * condem everyone to working round a clunky interface for ever afterwards. * * @copyright 1999 onwards Martin Dougiamas {@link http://moodle.com} * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class question_type { protected $fileoptions = array( 'subdirs' => true, 'maxfiles' => -1, 'maxbytes' => 0, ); public function __construct() { } /** * @return string the name of this question type. */ public function name() { return substr(get_class($this), 6); } /** * @return string the full frankenstyle name for this plugin. */ public function plugin_name() { return get_class($this); } /** * @return string the name of this question type in the user's language. * You should not need to override this method, the default behaviour should be fine. */ public function local_name() { return get_string('pluginname', $this->plugin_name()); } /** * The name this question should appear as in the create new question * dropdown. Override this method to return false if you don't want your * question type to be createable, for example if it is an abstract base type, * otherwise, you should not need to override this method. * * @return mixed the desired string, or false to hide this question type in the menu. */ public function menu_name() { return $this->local_name(); } /** * @return bool override this to return false if this is not really a * question type, for example the description question type is not * really a question type. */ public function is_real_question_type() { return true; } /** * @return bool true if this question type sometimes requires manual grading. */ public function is_manual_graded() { return false; } /** * @param object $question a question of this type. * @param string $otherquestionsinuse comma-separate list of other question ids in this attempt. * @return bool true if a particular instance of this question requires manual grading. */ public function is_question_manual_graded($question, $otherquestionsinuse) { return $this->is_manual_graded(); } /** * @return bool true if this question type can be used by the random question type. */ public function is_usable_by_random() { return true; } /** * Whether this question type can perform a frequency analysis of student * responses. * * If this method returns true, you must implement the get_possible_responses * method, and the question_definition class must implement the * classify_response method. * * @return bool whether this report can analyse all the student responses * for things like the quiz statistics report. */ public function can_analyse_responses() { // This works in most cases. return !$this->is_manual_graded(); } /** * @return whether the question_answers.answer field needs to have * restore_decode_content_links_worker called on it. */ public function has_html_answers() { return false; } /** * If your question type has a table that extends the question table, and * you want the base class to automatically save, backup and restore the extra fields, * override this method to return an array wherer the first element is the table name, * and the subsequent entries are the column names (apart from id and questionid). * * @return mixed array as above, or null to tell the base class to do nothing. */ public function extra_question_fields() { return null; } /** * If you use extra_question_fields, overload this function to return question id field name * in case you table use another name for this column */ public function questionid_column_name() { return 'questionid'; } /** * If your question type has a table that extends the question_answers table, * make this method return an array wherer the first element is the table name, * and the subsequent entries are the column names (apart from id and answerid). * * @return mixed array as above, or null to tell the base class to do nothing. */ public function extra_answer_fields() { return null; } /** * If the quetsion type uses files in responses, then this method should * return an array of all the response variables that might have corresponding * files. For example, the essay qtype returns array('attachments', 'answers'). * * @return array response variable names that may have associated files. */ public function response_file_areas() { return array(); } /** * Return an instance of the question editing form definition. This looks for a * class called edit_{$this->name()}_question_form in the file * question/type/{$this->name()}/edit_{$this->name()}_question_form.php * and if it exists returns an instance of it. * * @param string $submiturl passed on to the constructor call. * @return object an instance of the form definition, or null if one could not be found. */ public function create_editing_form($submiturl, $question, $category, $contexts, $formeditable) { global $CFG; require_once($CFG->dirroot . '/question/type/edit_question_form.php'); $definitionfile = $CFG->dirroot . '/question/type/' . $this->name() . '/edit_' . $this->name() . '_form.php'; if (!is_readable($definitionfile) || !is_file($definitionfile)) { throw new coding_exception($this->plugin_name() . ' is missing the definition of its editing formin file ' . $definitionfile . '.'); } require_once($definitionfile); $classname = $this->plugin_name() . '_edit_form'; if (!class_exists($classname)) { throw new coding_exception($this->plugin_name() . ' does not define the class ' . $this->plugin_name() . '_edit_form.'); } return new $classname($submiturl, $question, $category, $contexts, $formeditable); } /** * @return string the full path of the folder this plugin's files live in. */ public function plugin_dir() { global $CFG; return $CFG->dirroot . '/question/type/' . $this->name(); } /** * @return string the URL of the folder this plugin's files live in. */ public function plugin_baseurl() { global $CFG; return $CFG->wwwroot . '/question/type/' . $this->name(); } /** * Get extra actions for a question of this type to add to the question bank edit menu. * * This method is called if the {@link edit_menu_column} is being used in the * question bank, which it is by default since Moodle 3.8. If applicable for * your question type, you can return arn array of {@link action_menu_link}s. * These will be added at the end of the Edit menu for this question. * * The $question object passed in will have a hard-to-predict set of fields, * because the fields present depend on which columns are included in the * question bank view. However, you can rely on 'id', 'createdby', * 'contextid', 'hidden' and 'category' (id) being present, and so you * can call question_has_capability_on without causing performance problems. * * @param stdClass $question the available information about the particular question the action is for. * @return action_menu_link[] any actions you want to add to the Edit menu for this question. */ public function get_extra_question_bank_actions(stdClass $question): array { return []; } /** * This method should be overriden if you want to include a special heading or some other * html on a question editing page besides the question editing form. * * @param question_edit_form $mform a child of question_edit_form * @param object $question * @param string $wizardnow is '' for first page. */ public function display_question_editing_page($mform, $question, $wizardnow) { global $OUTPUT; $heading = $this->get_heading(empty($question->id)); echo $OUTPUT->heading_with_help($heading, 'pluginname', $this->plugin_name()); $mform->display(); } /** * Method called by display_question_editing_page and by question.php to get * heading for breadcrumbs. * * @return string the heading */ public function get_heading($adding = false) { if ($adding) { $string = 'pluginnameadding'; } else { $string = 'pluginnameediting'; } return get_string($string, $this->plugin_name()); } /** * Set any missing settings for this question to the default values. This is * called before displaying the question editing form. * * @param object $questiondata the question data, loaded from the databsae, * or more likely a newly created question object that is only partially * initialised. */ public function set_default_options($questiondata) { } /**
> * Return default value for a given form element either from user_preferences table or $default. * Saves (creates or updates) a question. > * * > * @param string $name the name of the form element. * Given some question info and some data about the answers > * @param mixed $default default value. * this function parses, organises and saves the question > * @return string|null default value for a given form element. * It is used by {@link question.php} when saving new data from > */ * a form, and also by {@link import.php} when importing questions > public function get_default_value(string $name, $default): ?string { * This function in turn calls {@link save_question_options} > return get_user_preferences($this->plugin_name() . '_' . $name, $default ?? '0'); * to save question-type specific data. > } * > * Whether we are saving a new question or updating an existing one can be > /** * determined by testing !empty($question->id). If it is not empty, we are updating. > * Save the default value for a given form element in user_preferences table. * > * * The question will be saved in category $form->category. > * @param string $name the name of the value to set. * > * @param string $value the setting value. * @param object $question the question object which should be updated. For a > */ * new question will be mostly empty. > public function set_default_value(string $name, string $value): void { * @param object $form the object containing the information to save, as if > set_user_preference($this->plugin_name() . '_' . $name, $value); * from the question editing form. > } * @param object $course not really used any more. > * @return object On success, return the new question object. On failure, > /** * return an object as follows. If the error object has an errors field, > * Save question defaults when creating new questions. * display that as an error message. Otherwise, the editing form will be > * * redisplayed with validation errors, from validation_errors field, which > * @param stdClass $fromform data from the form. * is itself an object, shown next to the form fields. (I don't think this > */ * is accurate any more.) > public function save_defaults_for_new_questions(stdClass $fromform): void { */ > // Some question types may not make use of the certain form elements, so public function save_question($question, $form) { > // we need to do a check on the following generic form elements. For instance, global $USER, $DB; > // 'defaultmark' is not use in qtype_multianswer and 'penalty' in not used in > // qtype_essay and qtype_recordrtc. // The actual update/insert done with multiple DB access, so we do it in a transaction. > if (isset($fromform->defaultmark)) { $transaction = $DB->start_delegated_transaction (); > $this->set_default_value('defaultmark', $fromform->defaultmark); > } list($question->category) = explode(',', $form->category); > if (isset($fromform->penalty)) { $context = $this->get_context_by_category_id($question->category); > $this->set_default_value('penalty', $fromform->penalty); > } // This default implementation is suitable for most > } // question types. > > /**
< list($question->category) = explode(',', $form->category); < $context = $this->get_context_by_category_id($question->category);
> list($form->category) = explode(',', $form->category); > $context = $this->get_context_by_category_id($form->category); > $question->category = $form->category;
$question->parent = isset($form->parent) ? $form->parent : 0; $question->length = $this->actual_number_of_questions($question); $question->penalty = isset($form->penalty) ? $form->penalty : 0; // The trim call below has the effect of casting any strange values received, // like null or false, to an appropriate string, so we only need to test for // missing values. Be careful not to break the value '0' here. if (!isset($form->questiontext['text'])) { $question->questiontext = ''; } else { $question->questiontext = trim($form->questiontext['text']); } $question->questiontextformat = !empty($form->questiontext['format']) ? $form->questiontext['format'] : 0; if (empty($form->generalfeedback['text'])) { $question->generalfeedback = ''; } else { $question->generalfeedback = trim($form->generalfeedback['text']); } $question->generalfeedbackformat = !empty($form->generalfeedback['format']) ? $form->generalfeedback['format'] : 0; if ($question->name === '') { $question->name = shorten_text(strip_tags($form->questiontext['text']), 15); if ($question->name === '') { $question->name = '-'; } } if ($question->penalty > 1 or $question->penalty < 0) { $question->errors['penalty'] = get_string('invalidpenalty', 'question'); } if (isset($form->defaultmark)) { $question->defaultmark = $form->defaultmark; }
> // Only create a new bank entry if the question is not a new version (New question or duplicating a question). if (isset($form->idnumber)) { > $questionbankentry = null; if ((string) $form->idnumber === '') { > if (isset($question->id)) { $question->idnumber = null; > $oldparent = $question->id; } else { > if (!empty($question->id)) { // While this check already exists in the form validation, > // Get the bank entry record where the question is referenced. // this is a backstop preventing unnecessary errors. > $questionbankentry = get_question_bank_entry($question->id); // Only set the idnumber if it has changed and will not cause a unique index violation. > } if (strpos($form->category, ',') !== false) { > } list($category, $categorycontextid) = explode(',', $form->category); > } else { > // Get the bank entry old id (this is when there are questions related with a parent, e.g.: qtype_multianswers). $category = $form->category; > if (isset($question->oldid)) { } > if (!empty($question->oldid)) { if (!$DB->record_exists('question', > $questionbankentry = get_question_bank_entry($question->oldid); ['idnumber' => $form->idnumber, 'category' => $category])) { > } $question->idnumber = $form->idnumber; > } } > } > // Always creates a new question and version record. } > // Set the unique code. > $question->stamp = make_unique_id_code(); // If the question is new, create it. > $question->createdby = $USER->id; $newquestion = false; > $question->timecreated = time(); if (empty($question->id)) { > // Set the unique code. > // Idnumber validation. $question->stamp = make_unique_id_code(); > $question->idnumber = null;
< if (!$DB->record_exists('question', < ['idnumber' => $form->idnumber, 'category' => $category])) {
> $params = ['idnumber' => $form->idnumber, 'categoryid' => $category]; > $andcondition = ''; > if (isset($question->id) && isset($questionbankentry->id)) { > $andcondition = 'AND qbe.id != :notid'; > $params['notid'] = $questionbankentry->id; > } > $sql = "SELECT qbe.id > FROM {question_bank_entries} qbe > WHERE qbe.idnumber = :idnumber > AND qbe.questioncategoryid = :categoryid > $andcondition"; > if (!$DB->record_exists_sql($sql, $params)) {
< // If the question is new, create it. < $newquestion = false; < if (empty($question->id)) { < // Set the unique code. < $question->stamp = make_unique_id_code(); < $question->createdby = $USER->id; < $question->timecreated = time();
> // Create the question.
< $newquestion = true;
> if (!$questionbankentry) { > // Create a record for question_bank_entries, question_versions and question_references. > $questionbankentry = new \stdClass(); > $questionbankentry->questioncategoryid = $form->category; > $questionbankentry->idnumber = $question->idnumber; > $questionbankentry->ownerid = $question->createdby; > $questionbankentry->id = $DB->insert_record('question_bank_entries', $questionbankentry); > } else { > $questionbankentryold = new \stdClass(); > $questionbankentryold->id = $questionbankentry->id; > $questionbankentryold->idnumber = $question->idnumber; > $DB->update_record('question_bank_entries', $questionbankentryold); > } > > // Create question_versions records. > $questionversion = new \stdClass(); > $questionversion->questionbankentryid = $questionbankentry->id; > $questionversion->questionid = $question->id; > // Get the version and status from the parent question if parent is set. > if (!$question->parent) { > // Get the status field. It comes from the form, but for testing we can. > $status = $form->status ?? $question->status ?? > \core_question\local\bank\question_version_status::QUESTION_STATUS_READY; > $questionversion->version = get_next_version($questionbankentry->id); > $questionversion->status = $status; > } else { > $parentversion = get_question_version($form->parent); > $questionversion->version = $parentversion[array_key_first($parentversion)]->version; > $questionversion->status = $parentversion[array_key_first($parentversion)]->status;
$question->timemodified = time();
> $questionversion->id = $DB->insert_record('question_versions', $questionversion);
if (!empty($question->questiontext) && !empty($form->questiontext['itemid'])) { $question->questiontext = file_save_draft_area_files($form->questiontext['itemid'], $context->id, 'question', 'questiontext', (int)$question->id, $this->fileoptions, $question->questiontext); } if (!empty($question->generalfeedback) && !empty($form->generalfeedback['itemid'])) { $question->generalfeedback = file_save_draft_area_files( $form->generalfeedback['itemid'], $context->id, 'question', 'generalfeedback', (int)$question->id, $this->fileoptions, $question->generalfeedback); } $DB->update_record('question', $question); // Now to save all the answers and type-specific options. $form->id = $question->id; $form->qtype = $question->qtype;
< $form->category = $question->category;
$form->questiontext = $question->questiontext; $form->questiontextformat = $question->questiontextformat; // Current context. $form->context = $context;
<
> // Old parent question id is used when there are questions related with a parent, e.g.: qtype_multianswers). > if (isset($oldparent)) { > $form->oldparent = $oldparent; > } else { > $form->oldparent = $question->parent; > }
$result = $this->save_question_options($form); if (!empty($result->error)) {
< print_error($result->error);
> throw new \moodle_exception($result->error);
} if (!empty($result->notice)) { notice($result->notice, "question.php?id={$question->id}"); } if (!empty($result->noticeyesno)) { throw new coding_exception( '$result->noticeyesno no longer supported in save_question.'); }
< // Give the question a unique version stamp determined by question_hash(). < $DB->set_field('question', 'version', question_hash($question), < array('id' => $question->id)); < < if ($newquestion) {
// Log the creation of this question. $event = \core\event\question_created::create_from_question_instance($question, $context); $event->trigger();
< } else { < // Log the update of this question. < $event = \core\event\question_updated::create_from_question_instance($question, $context); < $event->trigger(); < }
$transaction->allow_commit(); return $question; } /** * Saves question-type specific options * * This is called by {@link save_question()} to save the question-type specific data * @return object $result->error or $result->notice * @param object $question This holds the information from the editing form, * it is not a standard question object. */ public function save_question_options($question) { global $DB; $extraquestionfields = $this->extra_question_fields(); if (is_array($extraquestionfields)) { $question_extension_table = array_shift($extraquestionfields); $function = 'update_record'; $questionidcolname = $this->questionid_column_name(); $options = $DB->get_record($question_extension_table, array($questionidcolname => $question->id)); if (!$options) { $function = 'insert_record'; $options = new stdClass(); $options->$questionidcolname = $question->id; } foreach ($extraquestionfields as $field) { if (property_exists($question, $field)) { $options->$field = $question->$field; } } $DB->{$function}($question_extension_table, $options); } } /** * Save the answers, with any extra data. * * Questions that use answers will call it from {@link save_question_options()}. * @param object $question This holds the information from the editing form, * it is not a standard question object. * @return object $result->error or $result->notice */ public function save_question_answers($question) { global $DB; $context = $question->context; $oldanswers = $DB->get_records('question_answers', array('question' => $question->id), 'id ASC'); // We need separate arrays for answers and extra answer data, so no JOINS there. $extraanswerfields = $this->extra_answer_fields(); $isextraanswerfields = is_array($extraanswerfields); $extraanswertable = ''; $oldanswerextras = array(); if ($isextraanswerfields) { $extraanswertable = array_shift($extraanswerfields); if (!empty($oldanswers)) { $oldanswerextras = $DB->get_records_sql("SELECT * FROM {{$extraanswertable}} WHERE " . 'answerid IN (SELECT id FROM {question_answers} WHERE question = ' . $question->id . ')' ); } } // Insert all the new answers. foreach ($question->answer as $key => $answerdata) { // Check for, and ignore, completely blank answer from the form. if ($this->is_answer_empty($question, $key)) { continue; } // Update an existing answer if possible. $answer = array_shift($oldanswers); if (!$answer) { $answer = new stdClass(); $answer->question = $question->id; $answer->answer = ''; $answer->feedback = ''; $answer->id = $DB->insert_record('question_answers', $answer); } $answer = $this->fill_answer_fields($answer, $question, $key, $context); $DB->update_record('question_answers', $answer); if ($isextraanswerfields) { // Check, if this answer contains some extra field data. if ($this->is_extra_answer_fields_empty($question, $key)) { continue; } $answerextra = array_shift($oldanswerextras); if (!$answerextra) { $answerextra = new stdClass(); $answerextra->answerid = $answer->id; // Avoid looking for correct default for any possible DB field type // by setting real values. $answerextra = $this->fill_extra_answer_fields($answerextra, $question, $key, $context, $extraanswerfields); $answerextra->id = $DB->insert_record($extraanswertable, $answerextra); } else { // Update answerid, as record may be reused from another answer. $answerextra->answerid = $answer->id; $answerextra = $this->fill_extra_answer_fields($answerextra, $question, $key, $context, $extraanswerfields); $DB->update_record($extraanswertable, $answerextra); } } } if ($isextraanswerfields) { // Delete any left over extra answer fields records. $oldanswerextraids = array(); foreach ($oldanswerextras as $oldextra) { $oldanswerextraids[] = $oldextra->id; } $DB->delete_records_list($extraanswertable, 'id', $oldanswerextraids); } // Delete any left over old answer records. $fs = get_file_storage(); foreach ($oldanswers as $oldanswer) { $fs->delete_area_files($context->id, 'question', 'answerfeedback', $oldanswer->id); $DB->delete_records('question_answers', array('id' => $oldanswer->id)); } } /** * Returns true is answer with the $key is empty in the question data and should not be saved in DB. * * The questions using question_answers table may want to overload this. Default code will work * for shortanswer and similar question types. * @param object $questiondata This holds the information from the question editing form or import. * @param int $key A key of the answer in question. * @return bool True if answer shouldn't be saved in DB. */ protected function is_answer_empty($questiondata, $key) { return trim($questiondata->answer[$key]) == '' && $questiondata->fraction[$key] == 0 && html_is_blank($questiondata->feedback[$key]['text']); } /** * Return $answer, filling necessary fields for the question_answers table. * * The questions using question_answers table may want to overload this. Default code will work * for shortanswer and similar question types. * @param stdClass $answer Object to save data. * @param object $questiondata This holds the information from the question editing form or import. * @param int $key A key of the answer in question. * @param object $context needed for working with files. * @return $answer answer with filled data. */ protected function fill_answer_fields($answer, $questiondata, $key, $context) { $answer->answer = $questiondata->answer[$key]; $answer->fraction = $questiondata->fraction[$key]; $answer->feedback = $this->import_or_save_files($questiondata->feedback[$key], $context, 'question', 'answerfeedback', $answer->id); $answer->feedbackformat = $questiondata->feedback[$key]['format']; return $answer; } /** * Returns true if extra answer fields for answer with the $key is empty * in the question data and should not be saved in DB. * * Questions where extra answer fields are optional will want to overload this. * @param object $questiondata This holds the information from the question editing form or import. * @param int $key A key of the answer in question. * @return bool True if extra answer data shouldn't be saved in DB. */ protected function is_extra_answer_fields_empty($questiondata, $key) { // No extra answer data in base class. return true; } /** * Return $answerextra, filling necessary fields for the extra answer fields table. * * The questions may want to overload it to save files or do other data processing. * @param stdClass $answerextra Object to save data. * @param object $questiondata This holds the information from the question editing form or import. * @param int $key A key of the answer in question. * @param object $context needed for working with files. * @param array $extraanswerfields extra answer fields (without table name). * @return $answer answerextra with filled data. */ protected function fill_extra_answer_fields($answerextra, $questiondata, $key, $context, $extraanswerfields) { foreach ($extraanswerfields as $field) { // The $questiondata->$field[$key] won't work in PHP, break it down to two strings of code. $fieldarray = $questiondata->$field; $answerextra->$field = $fieldarray[$key]; } return $answerextra; } public function save_hints($formdata, $withparts = false) { global $DB; $context = $formdata->context; $oldhints = $DB->get_records('question_hints', array('questionid' => $formdata->id), 'id ASC'); $numhints = $this->count_hints_on_form($formdata, $withparts); for ($i = 0; $i < $numhints; $i += 1) { if (html_is_blank($formdata->hint[$i]['text'])) { $formdata->hint[$i]['text'] = ''; } if ($withparts) { $clearwrong = !empty($formdata->hintclearwrong[$i]); $shownumcorrect = !empty($formdata->hintshownumcorrect[$i]); } if ($this->is_hint_empty_in_form_data($formdata, $i, $withparts)) { continue; } // Update an existing hint if possible. $hint = array_shift($oldhints); if (!$hint) { $hint = new stdClass(); $hint->questionid = $formdata->id; $hint->hint = ''; $hint->id = $DB->insert_record('question_hints', $hint); } $hint->hint = $this->import_or_save_files($formdata->hint[$i], $context, 'question', 'hint', $hint->id); $hint->hintformat = $formdata->hint[$i]['format']; if ($withparts) { $hint->clearwrong = $clearwrong; $hint->shownumcorrect = $shownumcorrect; } $hint->options = $this->save_hint_options($formdata, $i, $withparts); $DB->update_record('question_hints', $hint); } // Delete any remaining old hints. $fs = get_file_storage(); foreach ($oldhints as $oldhint) { $fs->delete_area_files($context->id, 'question', 'hint', $oldhint->id); $DB->delete_records('question_hints', array('id' => $oldhint->id)); } } /** * Count number of hints on the form. * Overload if you use custom hint controls. * @param object $formdata the data from the form. * @param bool $withparts whether to take into account clearwrong and shownumcorrect options. * @return int count of hints on the form. */ protected function count_hints_on_form($formdata, $withparts) { if (!empty($formdata->hint)) { $numhints = max(array_keys($formdata->hint)) + 1; } else { $numhints = 0; } if ($withparts) { if (!empty($formdata->hintclearwrong)) { $numclears = max(array_keys($formdata->hintclearwrong)) + 1; } else { $numclears = 0; } if (!empty($formdata->hintshownumcorrect)) { $numshows = max(array_keys($formdata->hintshownumcorrect)) + 1; } else { $numshows = 0; } $numhints = max($numhints, $numclears, $numshows); } return $numhints; } /** * Determine if the hint with specified number is not empty and should be saved. * Overload if you use custom hint controls. * @param object $formdata the data from the form. * @param int $number number of hint under question. * @param bool $withparts whether to take into account clearwrong and shownumcorrect options. * @return bool is this particular hint data empty. */ protected function is_hint_empty_in_form_data($formdata, $number, $withparts) { if ($withparts) { return empty($formdata->hint[$number]['text']) && empty($formdata->hintclearwrong[$number]) && empty($formdata->hintshownumcorrect[$number]); } else { return empty($formdata->hint[$number]['text']); } } /** * Save additional question type data into the hint optional field. * Overload if you use custom hint information. * @param object $formdata the data from the form. * @param int $number number of hint to get options from. * @param bool $withparts whether question have parts. * @return string value to save into the options field of question_hints table. */ protected function save_hint_options($formdata, $number, $withparts) { return null; // By default, options field is unused. } /** * Can be used to {@link save_question_options()} to transfer the combined * feedback fields from $formdata to $options. * @param object $options the $question->options object being built. * @param object $formdata the data from the form. * @param object $context the context the quetsion is being saved into. * @param bool $withparts whether $options->shownumcorrect should be set. */ protected function save_combined_feedback_helper($options, $formdata, $context, $withparts = false) { $options->correctfeedback = $this->import_or_save_files($formdata->correctfeedback, $context, 'question', 'correctfeedback', $formdata->id); $options->correctfeedbackformat = $formdata->correctfeedback['format']; $options->partiallycorrectfeedback = $this->import_or_save_files( $formdata->partiallycorrectfeedback, $context, 'question', 'partiallycorrectfeedback', $formdata->id); $options->partiallycorrectfeedbackformat = $formdata->partiallycorrectfeedback['format']; $options->incorrectfeedback = $this->import_or_save_files($formdata->incorrectfeedback, $context, 'question', 'incorrectfeedback', $formdata->id); $options->incorrectfeedbackformat = $formdata->incorrectfeedback['format']; if ($withparts) { $options->shownumcorrect = !empty($formdata->shownumcorrect); } return $options; } /** * Loads the question type specific options for the question. * * This function loads any question type specific options for the * question from the database into the question object. This information * is placed in the $question->options field. A question type is * free, however, to decide on a internal structure of the options field. * @return bool Indicates success or failure. * @param object $question The question object for the question. This object * should be updated to include the question type * specific information (it is passed by reference). */ public function get_question_options($question) {
< global $CFG, $DB, $OUTPUT;
> global $DB, $OUTPUT;
if (!isset($question->options)) { $question->options = new stdClass(); } $extraquestionfields = $this->extra_question_fields(); if (is_array($extraquestionfields)) { $question_extension_table = array_shift($extraquestionfields); $extra_data = $DB->get_record($question_extension_table, array($this->questionid_column_name() => $question->id), implode(', ', $extraquestionfields)); if ($extra_data) { foreach ($extraquestionfields as $field) { $question->options->$field = $extra_data->$field; } } else { echo $OUTPUT->notification('Failed to load question options from the table ' . $question_extension_table . ' for questionid ' . $question->id); return false; } } $extraanswerfields = $this->extra_answer_fields(); if (is_array($extraanswerfields)) { $answerextensiontable = array_shift($extraanswerfields); // Use LEFT JOIN in case not every answer has extra data. $question->options->answers = $DB->get_records_sql(" SELECT qa.*, qax." . implode(', qax.', $extraanswerfields) . ' FROM {question_answers} qa ' . " LEFT JOIN {{$answerextensiontable}} qax ON qa.id = qax.answerid WHERE qa.question = ? ORDER BY qa.id", array($question->id)); if (!$question->options->answers) { echo $OUTPUT->notification('Failed to load question answers from the table ' . $answerextensiontable . 'for questionid ' . $question->id); return false; } } else { // Don't check for success or failure because some question types do // not use the answers table. $question->options->answers = $DB->get_records('question_answers', array('question' => $question->id), 'id ASC'); } $question->hints = $DB->get_records('question_hints', array('questionid' => $question->id), 'id ASC'); return true; } /** * Create an appropriate question_definition for the question of this type * using data loaded from the database. * @param object $questiondata the question data loaded from the database. * @return question_definition the corresponding question_definition. */ public function make_question($questiondata) { $question = $this->make_question_instance($questiondata); $this->initialise_question_instance($question, $questiondata); return $question; } /** * Create an appropriate question_definition for the question of this type * using data loaded from the database. * @param object $questiondata the question data loaded from the database. * @return question_definition an instance of the appropriate question_definition subclass. * Still needs to be initialised. */ protected function make_question_instance($questiondata) { question_bank::load_question_definition_classes($this->name()); $class = 'qtype_' . $this->name() . '_question'; return new $class(); } /** * Initialise the common question_definition fields. * @param question_definition $question the question_definition we are creating. * @param object $questiondata the question data loaded from the database. */ protected function initialise_question_instance(question_definition $question, $questiondata) { $question->id = $questiondata->id; $question->category = $questiondata->category; $question->contextid = $questiondata->contextid; $question->parent = $questiondata->parent; $question->qtype = $this; $question->name = $questiondata->name; $question->questiontext = $questiondata->questiontext; $question->questiontextformat = $questiondata->questiontextformat; $question->generalfeedback = $questiondata->generalfeedback; $question->generalfeedbackformat = $questiondata->generalfeedbackformat; $question->defaultmark = $questiondata->defaultmark + 0; $question->length = $questiondata->length; $question->penalty = $questiondata->penalty; $question->stamp = $questiondata->stamp;
< $question->version = $questiondata->version; < $question->hidden = $questiondata->hidden; < $question->idnumber = $questiondata->idnumber;
$question->timecreated = $questiondata->timecreated; $question->timemodified = $questiondata->timemodified; $question->createdby = $questiondata->createdby; $question->modifiedby = $questiondata->modifiedby;
> $this->initialise_core_question_metadata($question, $questiondata); // Fill extra question fields values. >
$extraquestionfields = $this->extra_question_fields(); if (is_array($extraquestionfields)) { // Omit table name. array_shift($extraquestionfields); foreach ($extraquestionfields as $field) { $question->$field = $questiondata->options->$field; } } $this->initialise_question_hints($question, $questiondata);
> } > // Add the custom fields. > $this->initialise_custom_fields($question, $questiondata); /** > } * Initialise question_definition::hints field. > * @param question_definition $question the question_definition we are creating. > /** * @param object $questiondata the question data loaded from the database. > * Initialise the question metadata. */ > * protected function initialise_question_hints(question_definition $question, $questiondata) { > * @param question_definition $question the question_definition we are creating. if (empty($questiondata->hints)) { > * @param object $questiondata the question data loaded from the database. return; > */ } > protected function initialise_core_question_metadata(question_definition $question, $questiondata) { foreach ($questiondata->hints as $hint) { > $fields = $question->hints[] = $this->make_hint($hint); > [ } > 'status', } > 'versionid', > 'version', /** > 'questionbankentryid', * Create a question_hint, or an appropriate subclass for this question, > 'idnumber', * from a row loaded from the database. > ]; * @param object $hint the DB row from the question hints table. > * @return question_hint > foreach ($fields as $field) { */ > if (isset($questiondata->{$field})) { protected function make_hint($hint) { > $question->{$field} = $questiondata->{$field}; return question_hint::load_from_record($hint); > } } > }
/**
> * Initialise question custom fields. * Initialise the combined feedback fields. > * @param question_definition $question the question_definition we are creating. * @param question_definition $question the question_definition we are creating. > * @param object $questiondata the question data loaded from the database. * @param object $questiondata the question data loaded from the database. > */ * @param bool $withparts whether to set the shownumcorrect field. > protected function initialise_custom_fields(question_definition $question, $questiondata) { */ > if (!empty($questiondata->customfields)) { protected function initialise_combined_feedback(question_definition $question, > $question->customfields = $questiondata->customfields; $questiondata, $withparts = false) { > } $question->correctfeedback = $questiondata->options->correctfeedback; > } $question->correctfeedbackformat = $questiondata->options->correctfeedbackformat; > $question->partiallycorrectfeedback = $questiondata->options->partiallycorrectfeedback; > /**
$question->partiallycorrectfeedbackformat = $questiondata->options->partiallycorrectfeedbackformat; $question->incorrectfeedback = $questiondata->options->incorrectfeedback; $question->incorrectfeedbackformat = $questiondata->options->incorrectfeedbackformat; if ($withparts) { $question->shownumcorrect = $questiondata->options->shownumcorrect; } } /** * Initialise question_definition::answers field. * @param question_definition $question the question_definition we are creating. * @param object $questiondata the question data loaded from the database. * @param bool $forceplaintextanswers most qtypes assume that answers are * FORMAT_PLAIN, and dont use the answerformat DB column (it contains * the default 0 = FORMAT_MOODLE). Therefore, by default this method * ingores answerformat. Pass false here to use answerformat. For example * multichoice does this. */ protected function initialise_question_answers(question_definition $question, $questiondata, $forceplaintextanswers = true) { $question->answers = array(); if (empty($questiondata->options->answers)) { return; } foreach ($questiondata->options->answers as $a) { $question->answers[$a->id] = $this->make_answer($a); if (!$forceplaintextanswers) { $question->answers[$a->id]->answerformat = $a->answerformat; } } } /** * Create a question_answer, or an appropriate subclass for this question, * from a row loaded from the database. * @param object $answer the DB row from the question_answers table plus extra answer fields. * @return question_answer */ protected function make_answer($answer) { return new question_answer($answer->id, $answer->answer, $answer->fraction, $answer->feedback, $answer->feedbackformat); } /** * Deletes the question-type specific data when a question is deleted. * @param int $question the question being deleted. * @param int $contextid the context this quesiotn belongs to. */ public function delete_question($questionid, $contextid) { global $DB; $this->delete_files($questionid, $contextid); $extraquestionfields = $this->extra_question_fields(); if (is_array($extraquestionfields)) { $question_extension_table = array_shift($extraquestionfields); $DB->delete_records($question_extension_table, array($this->questionid_column_name() => $questionid)); } $extraanswerfields = $this->extra_answer_fields(); if (is_array($extraanswerfields)) { $answer_extension_table = array_shift($extraanswerfields); $DB->delete_records_select($answer_extension_table, 'answerid IN (SELECT qa.id FROM {question_answers} qa WHERE qa.question = ?)', array($questionid)); } $DB->delete_records('question_answers', array('question' => $questionid)); $DB->delete_records('question_hints', array('questionid' => $questionid)); } /** * Returns the number of question numbers which are used by the question * * This function returns the number of question numbers to be assigned * to the question. Most question types will have length one; they will be * assigned one number. The 'description' type, however does not use up a * number and so has a length of zero. Other question types may wish to * handle a bundle of questions and hence return a number greater than one. * @return int The number of question numbers which should be * assigned to the question. * @param object $question The question whose length is to be determined. * Question type specific information is included. */ public function actual_number_of_questions($question) { // By default, each question is given one number. return 1; } /** * Calculate the score a monkey would get on a question by clicking randomly. * * Some question types have significant non-zero average expected score * of the response is just selected randomly. For example 50% for a * true-false question. It is useful to know what this is. For example * it gets shown in the quiz statistics report. * * For almost any open-ended question type (E.g. shortanswer or numerical) * this should be 0. * * For selective response question types (e.g. multiple choice), you can probably compute this. * * For particularly complicated question types the may be impossible or very * difficult to compute. In this case return null. (Or, if the expected score * is very tiny even though the exact value is unknown, it may appropriate * to return 0.) * * @param stdClass $questiondata data defining a question, as returned by * question_bank::load_question_data(). * @return number|null either a fraction estimating what the student would * score by guessing, or null, if it is not possible to estimate. */ public function get_random_guess_score($questiondata) { return 0; } /** * Whether or not to break down question stats and response analysis, for a question defined by $questiondata. * * @param object $questiondata The full question definition data. * @return bool */ public function break_down_stats_and_response_analysis_by_variant($questiondata) { return true; } /** * This method should return all the possible types of response that are * recognised for this question. * * The question is modelled as comprising one or more subparts. For each * subpart, there are one or more classes that that students response * might fall into, each of those classes earning a certain score. * * For example, in a shortanswer question, there is only one subpart, the * text entry field. The response the student gave will be classified according * to which of the possible $question->options->answers it matches. * * For the matching question type, there will be one subpart for each * question stem, and for each stem, each of the possible choices is a class * of student's response. * * A response is an object with two fields, ->responseclass is a string * presentation of that response, and ->fraction, the credit for a response * in that class. * * Array keys have no specific meaning, but must be unique, and must be * the same if this function is called repeatedly. * * @param object $question the question definition data. * @return array keys are subquestionid, values are arrays of possible * responses to that subquestion. */ public function get_possible_responses($questiondata) { return array(); } /** * Utility method used by {@link qtype_renderer::head_code()}. It looks * for any of the files script.js or script.php that exist in the plugin * folder and ensures they get included. */ public function find_standard_scripts() { global $PAGE; $plugindir = $this->plugin_dir(); $plugindirrel = 'question/type/' . $this->name(); if (file_exists($plugindir . '/script.js')) { $PAGE->requires->js('/' . $plugindirrel . '/script.js'); } if (file_exists($plugindir . '/script.php')) { $PAGE->requires->js('/' . $plugindirrel . '/script.php'); } } /** * Returns true if the editing wizard is finished, false otherwise. * * The default implementation returns true, which is suitable for all question- * types that only use one editing form. This function is used in * question.php to decide whether we can regrade any states of the edited * question and redirect to edit.php. * * The dataset dependent question-type, which is extended by the calculated * question-type, overwrites this method because it uses multiple pages (i.e. * a wizard) to set up the question and associated datasets. * * @param object $form The data submitted by the previous page. * * @return bool Whether the wizard's last page was submitted or not. */ public function finished_edit_wizard($form) { // In the default case there is only one edit page. return true; } // IMPORT/EXPORT FUNCTIONS --------------------------------- . /* * Imports question from the Moodle XML format * * Imports question using information from extra_question_fields function * If some of you fields contains id's you'll need to reimplement this */ public function import_from_xml($data, $question, qformat_xml $format, $extra=null) { $question_type = $data['@']['type']; if ($question_type != $this->name()) { return false; } $extraquestionfields = $this->extra_question_fields(); if (!is_array($extraquestionfields)) { return false; } // Omit table name. array_shift($extraquestionfields); $qo = $format->import_headers($data); $qo->qtype = $question_type; foreach ($extraquestionfields as $field) { $qo->$field = $format->getpath($data, array('#', $field, 0, '#'), ''); } // Run through the answers. $answers = $data['#']['answer']; $a_count = 0; $extraanswersfields = $this->extra_answer_fields(); if (is_array($extraanswersfields)) { array_shift($extraanswersfields); } foreach ($answers as $answer) { $ans = $format->import_answer($answer); if (!$this->has_html_answers()) { $qo->answer[$a_count] = $ans->answer['text']; } else { $qo->answer[$a_count] = $ans->answer; } $qo->fraction[$a_count] = $ans->fraction; $qo->feedback[$a_count] = $ans->feedback; if (is_array($extraanswersfields)) { foreach ($extraanswersfields as $field) { $qo->{$field}[$a_count] = $format->getpath($answer, array('#', $field, 0, '#'), ''); } } ++$a_count; } return $qo; } /* * Export question to the Moodle XML format * * Export question using information from extra_question_fields function * If some of you fields contains id's you'll need to reimplement this */ public function export_to_xml($question, qformat_xml $format, $extra=null) { $extraquestionfields = $this->extra_question_fields(); if (!is_array($extraquestionfields)) { return false; } // Omit table name. array_shift($extraquestionfields); $expout=''; foreach ($extraquestionfields as $field) { $exportedvalue = $format->xml_escape($question->options->$field); $expout .= " <{$field}>{$exportedvalue}</{$field}>\n"; } $extraanswersfields = $this->extra_answer_fields(); if (is_array($extraanswersfields)) { array_shift($extraanswersfields); } foreach ($question->options->answers as $answer) { $extra = ''; if (is_array($extraanswersfields)) { foreach ($extraanswersfields as $field) { $exportedvalue = $format->xml_escape($answer->$field); $extra .= " <{$field}>{$exportedvalue}</{$field}>\n"; } } $expout .= $format->write_answer($answer, $extra); } return $expout; } /** * Abstract function implemented by each question type. It runs all the code * required to set up and save a question of any type for testing purposes. * Alternate DB table prefix may be used to facilitate data deletion. */ public function generate_test($name, $courseid=null) { $form = new stdClass(); $form->name = $name; $form->questiontextformat = 1; $form->questiontext = 'test question, generated by script'; $form->defaultmark = 1; $form->penalty = 0.3333333;
> $form->status = \core_question\local\bank\question_version_status::QUESTION_STATUS_READY;
$form->generalfeedback = "Well done"; $context = context_course::instance($courseid); $newcategory = question_make_default_categories(array($context)); $form->category = $newcategory->id . ',1'; $question = new stdClass(); $question->courseid = $courseid; $question->qtype = $this->qtype; return array($form, $question); } /** * Get question context by category id * @param int $category * @return object $context */ protected function get_context_by_category_id($category) { global $DB; $contextid = $DB->get_field('question_categories', 'contextid', array('id'=>$category)); $context = context::instance_by_id($contextid, IGNORE_MISSING); return $context; } /** * Save the file belonging to one text field. * * @param array $field the data from the form (or from import). This will * normally have come from the formslib editor element, so it will be an * array with keys 'text', 'format' and 'itemid'. However, when we are * importing, it will be an array with keys 'text', 'format' and 'files' * @param object $context the context the question is in. * @param string $component indentifies the file area question. * @param string $filearea indentifies the file area questiontext, * generalfeedback, answerfeedback, etc. * @param int $itemid identifies the file area. * * @return string the text for this field, after files have been processed. */ protected function import_or_save_files($field, $context, $component, $filearea, $itemid) { if (!empty($field['itemid'])) { // This is the normal case. We are safing the questions editing form. return file_save_draft_area_files($field['itemid'], $context->id, $component, $filearea, $itemid, $this->fileoptions, trim($field['text'])); } else if (!empty($field['files'])) { // This is the case when we are doing an import. foreach ($field['files'] as $file) { $this->import_file($context, $component, $filearea, $itemid, $file); } } return trim($field['text']); } /** * Move all the files belonging to this question from one context to another. * @param int $questionid the question being moved. * @param int $oldcontextid the context it is moving from. * @param int $newcontextid the context it is moving to. */ public function move_files($questionid, $oldcontextid, $newcontextid) { $fs = get_file_storage(); $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'questiontext', $questionid); $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'generalfeedback', $questionid); } /** * Move all the files belonging to this question's answers when the question * is moved from one context to another. * @param int $questionid the question being moved. * @param int $oldcontextid the context it is moving from. * @param int $newcontextid the context it is moving to. * @param bool $answerstoo whether there is an 'answer' question area, * as well as an 'answerfeedback' one. Default false. */ protected function move_files_in_answers($questionid, $oldcontextid, $newcontextid, $answerstoo = false) { global $DB; $fs = get_file_storage(); $answerids = $DB->get_records_menu('question_answers', array('question' => $questionid), 'id', 'id,1'); foreach ($answerids as $answerid => $notused) { if ($answerstoo) { $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'answer', $answerid); } $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'answerfeedback', $answerid); } } /** * Move all the files belonging to this question's hints when the question * is moved from one context to another. * @param int $questionid the question being moved. * @param int $oldcontextid the context it is moving from. * @param int $newcontextid the context it is moving to. * @param bool $answerstoo whether there is an 'answer' question area, * as well as an 'answerfeedback' one. Default false. */ protected function move_files_in_hints($questionid, $oldcontextid, $newcontextid) { global $DB; $fs = get_file_storage(); $hintids = $DB->get_records_menu('question_hints', array('questionid' => $questionid), 'id', 'id,1'); foreach ($hintids as $hintid => $notused) { $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'hint', $hintid); } } /** * Move all the files belonging to this question's answers when the question * is moved from one context to another. * @param int $questionid the question being moved. * @param int $oldcontextid the context it is moving from. * @param int $newcontextid the context it is moving to. * @param bool $answerstoo whether there is an 'answer' question area, * as well as an 'answerfeedback' one. Default false. */ protected function move_files_in_combined_feedback($questionid, $oldcontextid, $newcontextid) { global $DB; $fs = get_file_storage(); $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'correctfeedback', $questionid); $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'partiallycorrectfeedback', $questionid); $fs->move_area_files_to_new_context($oldcontextid, $newcontextid, 'question', 'incorrectfeedback', $questionid); } /** * Delete all the files belonging to this question. * @param int $questionid the question being deleted. * @param int $contextid the context the question is in. */ protected function delete_files($questionid, $contextid) { $fs = get_file_storage(); $fs->delete_area_files($contextid, 'question', 'questiontext', $questionid); $fs->delete_area_files($contextid, 'question', 'generalfeedback', $questionid); } /** * Delete all the files belonging to this question's answers. * @param int $questionid the question being deleted. * @param int $contextid the context the question is in. * @param bool $answerstoo whether there is an 'answer' question area, * as well as an 'answerfeedback' one. Default false. */ protected function delete_files_in_answers($questionid, $contextid, $answerstoo = false) { global $DB; $fs = get_file_storage(); $answerids = $DB->get_records_menu('question_answers', array('question' => $questionid), 'id', 'id,1'); foreach ($answerids as $answerid => $notused) { if ($answerstoo) { $fs->delete_area_files($contextid, 'question', 'answer', $answerid); } $fs->delete_area_files($contextid, 'question', 'answerfeedback', $answerid); } } /** * Delete all the files belonging to this question's hints. * @param int $questionid the question being deleted. * @param int $contextid the context the question is in. */ protected function delete_files_in_hints($questionid, $contextid) { global $DB; $fs = get_file_storage(); $hintids = $DB->get_records_menu('question_hints', array('questionid' => $questionid), 'id', 'id,1'); foreach ($hintids as $hintid => $notused) { $fs->delete_area_files($contextid, 'question', 'hint', $hintid); } } /** * Delete all the files belonging to this question's answers. * @param int $questionid the question being deleted. * @param int $contextid the context the question is in. * @param bool $answerstoo whether there is an 'answer' question area, * as well as an 'answerfeedback' one. Default false. */ protected function delete_files_in_combined_feedback($questionid, $contextid) { global $DB; $fs = get_file_storage(); $fs->delete_area_files($contextid, 'question', 'correctfeedback', $questionid); $fs->delete_area_files($contextid, 'question', 'partiallycorrectfeedback', $questionid); $fs->delete_area_files($contextid, 'question', 'incorrectfeedback', $questionid); } public function import_file($context, $component, $filearea, $itemid, $file) { $fs = get_file_storage(); $record = new stdClass(); if (is_object($context)) { $record->contextid = $context->id; } else { $record->contextid = $context; } $record->component = $component; $record->filearea = $filearea; $record->itemid = $itemid; $record->filename = $file->name; $record->filepath = '/'; return $fs->create_file_from_string($record, $this->decode_file($file)); } protected function decode_file($file) { switch ($file->encoding) { case 'base64': default: return base64_decode($file->content); } } } /** * This class is used in the return value from * {@link question_type::get_possible_responses()}. * * @copyright 2010 The Open University * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class question_possible_response { /** * @var string the classification of this response the student gave to this * part of the question. Must match one of the responseclasses returned by * {@link question_type::get_possible_responses()}. */ public $responseclass; /** @var string the (partial) credit awarded for this responses. */ public $fraction; /** * Constructor, just an easy way to set the fields. * @param string $responseclassid see the field descriptions above. * @param string $response see the field descriptions above. * @param number $fraction see the field descriptions above. */ public function __construct($responseclass, $fraction) { $this->responseclass = $responseclass; $this->fraction = $fraction; } public static function no_response() { return new question_possible_response(get_string('noresponse', 'question'), 0); } }