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<?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/>.
/**
* This file defines the question usage class, and a few related classes.
*
* @package moodlecore
* @subpackage questionengine
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* This class keeps track of a group of questions that are being attempted,
* and which state, and so on, each one is currently in.
*
* A quiz attempt or a lesson attempt could use an instance of this class to
* keep track of all the questions in the attempt and process student submissions.
* It is basically a collection of {@question_attempt} objects.
*
* The questions being attempted as part of this usage are identified by an integer
* that is passed into many of the methods as $slot. ($question->id is not
* used so that the same question can be used more than once in an attempt.)
*
* Normally, calling code should be able to do everything it needs to be calling
* methods of this class. You should not normally need to get individual
* {@question_attempt} objects and play around with their inner workind, in code
* that it outside the quetsion engine.
*
* Instances of this class correspond to rows in the question_usages table.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_usage_by_activity {
/**
* @var integer|string the id for this usage. If this usage was loaded from
* the database, then this is the database id. Otherwise a unique random
* string is used.
*/
protected $id = null;
/**
* @var string name of an archetypal behaviour, that should be used
* by questions in this usage if possible.
*/
protected $preferredbehaviour = null;
/** @var context the context this usage belongs to. */
protected $context;
/** @var string plugin name of the plugin this usage belongs to. */
protected $owningcomponent;
/** @var array {@link question_attempt}s that make up this usage. */
protected $questionattempts = array();
/** @var question_usage_observer that tracks changes to this usage. */
protected $observer;
/**
* Create a new instance. Normally, calling code should use
* {@link question_engine::make_questions_usage_by_activity()} or
* {@link question_engine::load_questions_usage_by_activity()} rather than
* calling this constructor directly.
*
* @param string $component the plugin creating this attempt. For example mod_quiz.
* @param object $context the context this usage belongs to.
*/
public function __construct($component, $context) {
$this->owningcomponent = $component;
$this->context = $context;
$this->observer = new question_usage_null_observer();
}
/**
* @param string $behaviour the name of an archetypal behaviour, that should
* be used by questions in this usage if possible.
*/
public function set_preferred_behaviour($behaviour) {
$this->preferredbehaviour = $behaviour;
$this->observer->notify_modified();
}
/** @return string the name of the preferred behaviour. */
public function get_preferred_behaviour() {
return $this->preferredbehaviour;
}
/** @return context the context this usage belongs to. */
public function get_owning_context() {
return $this->context;
}
/** @return string the name of the plugin that owns this attempt. */
public function get_owning_component() {
return $this->owningcomponent;
}
/** @return int|string If this usage came from the database, then the id
* from the question_usages table is returned. Otherwise a random string is
* returned. */
public function get_id() {
if (is_null($this->id)) {
$this->id = random_string(10);
}
return $this->id;
}
/**
* For internal use only. Used by {@link question_engine_data_mapper} to set
* the id when a usage is saved to the database.
* @param int $id the newly determined id for this usage.
*/
public function set_id_from_database($id) {
$this->id = $id;
foreach ($this->questionattempts as $qa) {
$qa->set_usage_id($id);
}
}
/** @return question_usage_observer that is tracking changes made to this usage. */
public function get_observer() {
return $this->observer;
}
/**
* You should almost certainly not call this method from your code. It is for
* internal use only.
* @param question_usage_observer that should be used to tracking changes made to this usage.
*/
public function set_observer($observer) {
$this->observer = $observer;
foreach ($this->questionattempts as $qa) {
$qa->set_observer($observer);
}
}
/**
* Add another question to this usage.
*
* The added question is not started until you call {@link start_question()}
* on it.
*
* @param question_definition $question the question to add.
* @param number $maxmark the maximum this question will be marked out of in
* this attempt (optional). If not given, $question->defaultmark is used.
* @return int the number used to identify this question within this usage.
*/
public function add_question(question_definition $question, $maxmark = null) {
$qa = new question_attempt($question, $this->get_id(), $this->observer, $maxmark);
$qa->set_slot($this->next_slot_number());
$this->questionattempts[$this->next_slot_number()] = $qa;
$this->observer->notify_attempt_added($qa);
return $qa->get_slot();
}
/**
* Add another question to this usage, in the place of an existing slot.
* The question_attempt that was in that slot is moved to the end at a new
* slot number, which is returned.
*
* The added question is not started until you call {@link start_question()}
* on it.
*
* @param int $slot the slot-number of the question to replace.
* @param question_definition $question the question to add.
* @param number $maxmark the maximum this question will be marked out of in
* this attempt (optional). If not given, the max mark from the $qa we
* are replacing is used.
* @return int the new slot number of the question that was displaced.
*/
public function add_question_in_place_of_other($slot, question_definition $question, $maxmark = null) {
$newslot = $this->next_slot_number();
$oldqa = $this->get_question_attempt($slot);
$oldqa->set_slot($newslot);
$this->questionattempts[$newslot] = $oldqa;
if ($maxmark === null) {
$maxmark = $oldqa->get_max_mark();
}
$qa = new question_attempt($question, $this->get_id(), $this->observer, $maxmark);
$qa->set_slot($slot);
$this->questionattempts[$slot] = $qa;
$this->observer->notify_attempt_moved($oldqa, $slot);
$this->observer->notify_attempt_added($qa);
return $newslot;
}
/**
* The slot number that will be allotted to the next question added.
*/
public function next_slot_number() {
return count($this->questionattempts) + 1;
}
/**
* Get the question_definition for a question in this attempt.
* @param int $slot the number used to identify this question within this usage.
* @return question_definition the requested question object.
*/
public function get_question($slot) {
return $this->get_question_attempt($slot)->get_question();
}
/** @return array all the identifying numbers of all the questions in this usage. */
public function get_slots() {
return array_keys($this->questionattempts);
}
/** @return int the identifying number of the first question that was added to this usage. */
public function get_first_question_number() {
reset($this->questionattempts);
return key($this->questionattempts);
}
/** @return int the number of questions that are currently in this usage. */
public function question_count() {
return count($this->questionattempts);
}
/**
* Note the part of the {@link question_usage_by_activity} comment that explains
* that {@link question_attempt} objects should be considered part of the inner
* workings of the question engine, and should not, if possible, be accessed directly.
*
* @return question_attempt_iterator for iterating over all the questions being
* attempted. as part of this usage.
*/
public function get_attempt_iterator() {
return new question_attempt_iterator($this);
}
/**
* Check whether $number actually corresponds to a question attempt that is
* part of this usage. Throws an exception if not.
*
* @param int $slot a number allegedly identifying a question within this usage.
*/
protected function check_slot($slot) {
if (!array_key_exists($slot, $this->questionattempts)) {
throw new coding_exception('There is no question_attempt number ' . $slot .
' in this attempt.');
}
}
/**
* Note the part of the {@link question_usage_by_activity} comment that explains
* that {@link question_attempt} objects should be considered part of the inner
* workings of the question engine, and should not, if possible, be accessed directly.
*
* @param int $slot the number used to identify this question within this usage.
* @return question_attempt the corresponding {@link question_attempt} object.
*/
public function get_question_attempt($slot) {
$this->check_slot($slot);
return $this->questionattempts[$slot];
}
/**
* Get the current state of the attempt at a question.
* @param int $slot the number used to identify this question within this usage.
* @return question_state.
*/
public function get_question_state($slot) {
return $this->get_question_attempt($slot)->get_state();
}
/**
* @param int $slot the number used to identify this question within this usage.
* @param bool $showcorrectness Whether right/partial/wrong states should
* be distinguised.
* @return string A brief textual description of the current state.
*/
public function get_question_state_string($slot, $showcorrectness) {
return $this->get_question_attempt($slot)->get_state_string($showcorrectness);
}
/**
* @param int $slot the number used to identify this question within this usage.
* @param bool $showcorrectness Whether right/partial/wrong states should
* be distinguised.
* @return string a CSS class name for the current state.
*/
public function get_question_state_class($slot, $showcorrectness) {
return $this->get_question_attempt($slot)->get_state_class($showcorrectness);
}
/**
* Whether this attempt at a given question could be completed just by the
* student interacting with the question, before {@link finish_question()} is called.
*
* @param int $slot the number used to identify this question within this usage.
* @return boolean whether the attempt at the given question can finish naturally.
*/
public function can_question_finish_during_attempt($slot) {
return $this->get_question_attempt($slot)->can_finish_during_attempt();
}
/**
* Get the time of the most recent action performed on a question.
* @param int $slot the number used to identify this question within this usage.
* @return int timestamp.
*/
public function get_question_action_time($slot) {
return $this->get_question_attempt($slot)->get_last_action_time();
}
/**
* Get the current fraction awarded for the attempt at a question.
* @param int $slot the number used to identify this question within this usage.
* @return number|null The current fraction for this question, or null if one has
* not been assigned yet.
*/
public function get_question_fraction($slot) {
return $this->get_question_attempt($slot)->get_fraction();
}
/**
* Get the current mark awarded for the attempt at a question.
* @param int $slot the number used to identify this question within this usage.
* @return number|null The current mark for this question, or null if one has
* not been assigned yet.
*/
public function get_question_mark($slot) {
return $this->get_question_attempt($slot)->get_mark();
}
/**
* Get the maximum mark possible for the attempt at a question.
* @param int $slot the number used to identify this question within this usage.
* @return number the available marks for this question.
*/
public function get_question_max_mark($slot) {
return $this->get_question_attempt($slot)->get_max_mark();
}
/**
* Get the total mark for all questions in this usage.
* @return number The sum of marks of all the question_attempts in this usage.
*/
public function get_total_mark() {
$mark = 0;
foreach ($this->questionattempts as $qa) {
if ($qa->get_max_mark() > 0 && $qa->get_state() == question_state::$needsgrading) {
return null;
}
$mark += $qa->get_mark();
}
return $mark;
}
/**
* Get summary information about this usage.
*
* Some behaviours may be able to provide interesting summary information
* about the attempt as a whole, and this method provides access to that data.
* To see how this works, try setting a quiz to one of the CBM behaviours,
* and then look at the extra information displayed at the top of the quiz
* review page once you have sumitted an attempt.
*
* In the return value, the array keys are identifiers of the form
* qbehaviour_behaviourname_meaningfullkey. For qbehaviour_deferredcbm_highsummary.
* The values are arrays with two items, title and content. Each of these
* will be either a string, or a renderable.
*
* @param question_display_options $options display options to apply.
* @return array as described above.
*/
public function get_summary_information(question_display_options $options) {
return question_engine::get_behaviour_type($this->preferredbehaviour)
->summarise_usage($this, $options);
}
/**
* Get a simple textual summary of the question that was asked.
*
* @param int $slot the slot number of the question to summarise.
* @return string the question summary.
*/
public function get_question_summary($slot) {
return $this->get_question_attempt($slot)->get_question_summary();
}
/**
* Get a simple textual summary of response given.
*
* @param int $slot the slot number of the question to get the response summary for.
* @return string the response summary.
*/
public function get_response_summary($slot) {
return $this->get_question_attempt($slot)->get_response_summary();
}
/**
* Get a simple textual summary of the correct response to a question.
*
* @param int $slot the slot number of the question to get the right answer summary for.
* @return string the right answer summary.
*/
public function get_right_answer_summary($slot) {
return $this->get_question_attempt($slot)->get_right_answer_summary();
}
/**
* Return one of the bits of metadata for a particular question attempt in
* this usage.
* @param int $slot the slot number of the question of inereest.
* @param string $name the name of the metadata variable to return.
* @return string the value of that metadata variable.
*/
public function get_question_attempt_metadata($slot, $name) {
return $this->get_question_attempt($slot)->get_metadata($name);
}
/**
* Set some metadata for a particular question attempt in this usage.
* @param int $slot the slot number of the question of inerest.
* @param string $name the name of the metadata variable to return.
* @param string $value the value to set that metadata variable to.
*/
public function set_question_attempt_metadata($slot, $name, $value) {
$this->get_question_attempt($slot)->set_metadata($name, $value);
}
/**
* Get the {@link core_question_renderer}, in collaboration with appropriate
* {@link qbehaviour_renderer} and {@link qtype_renderer} subclasses, to generate the
* HTML to display this question.
* @param int $slot the number used to identify this question within this usage.
* @param question_display_options $options controls how the question is rendered.
* @param string|null $number The question number to display. 'i' is a special
* value that gets displayed as Information. Null means no number is displayed.
* @return string HTML fragment representing the question.
*/
public function render_question($slot, $options, $number = null) {
$options->context = $this->context;
return $this->get_question_attempt($slot)->render($options, $number);
}
/**
* Generate any bits of HTML that needs to go in the <head> tag when this question
* is displayed in the body.
* @param int $slot the number used to identify this question within this usage.
* @return string HTML fragment.
*/
public function render_question_head_html($slot) {
//$options->context = $this->context;
return $this->get_question_attempt($slot)->render_head_html();
}
/**
* Like {@link render_question()} but displays the question at the past step
* indicated by $seq, rather than showing the latest step.
*
* @param int $slot the number used to identify this question within this usage.
* @param int $seq the seq number of the past state to display.
* @param question_display_options $options controls how the question is rendered.
* @param string|null $number The question number to display. 'i' is a special
* value that gets displayed as Information. Null means no number is displayed.
* @return string HTML fragment representing the question.
*/
public function render_question_at_step($slot, $seq, $options, $number = null) {
$options->context = $this->context;
return $this->get_question_attempt($slot)->render_at_step(
$seq, $options, $number, $this->preferredbehaviour);
}
/**
* Checks whether the users is allow to be served a particular file.
* @param int $slot the number used to identify this question within this usage.
* @param question_display_options $options the options that control display of the question.
* @param string $component the name of the component we are serving files for.
* @param string $filearea the name of the file area.
* @param array $args the remaining bits of the file path.
* @param bool $forcedownload whether the user must be forced to download the file.
* @return bool true if the user can access this file.
*/
public function check_file_access($slot, $options, $component, $filearea,
$args, $forcedownload) {
return $this->get_question_attempt($slot)->check_file_access(
$options, $component, $filearea, $args, $forcedownload);
}
/**
* Replace a particular question_attempt with a different one.
*
* For internal use only. Used when reloading the state of a question from the
* database.
*
* @param int $slot the slot number of the question to replace.
* @param question_attempt $qa the question attempt to put in that place.
*/
public function replace_loaded_question_attempt_info($slot, $qa) {
$this->check_slot($slot);
$this->questionattempts[$slot] = $qa;
}
/**
* You should probably not use this method in code outside the question engine.
* The main reason for exposing it was for the benefit of unit tests.
* @param int $slot the number used to identify this question within this usage.
* @return string return the prefix that is pre-pended to field names in the HTML
* that is output.
*/
public function get_field_prefix($slot) {
return $this->get_question_attempt($slot)->get_field_prefix();
}
/**
* Get the number of variants available for the question in this slot.
* @param int $slot the number used to identify this question within this usage.
* @return int the number of variants available.
*/
public function get_num_variants($slot) {
return $this->get_question_attempt($slot)->get_question()->get_num_variants();
}
/**
* Get the variant of the question being used in a given slot.
* @param int $slot the number used to identify this question within this usage.
* @return int the variant of this question that is being used.
*/
public function get_variant($slot) {
return $this->get_question_attempt($slot)->get_variant();
}
/**
* Start the attempt at a question that has been added to this usage.
* @param int $slot the number used to identify this question within this usage.
* @param int $variant which variant of the question to use. Must be between
* 1 and ->get_num_variants($slot) inclusive. If not give, a variant is
* chosen at random.
* @param int|null $timenow optional, the timstamp to record for this action. Defaults to now.
*/
public function start_question($slot, $variant = null, $timenow = null) {
if (is_null($variant)) {
$variant = rand(1, $this->get_num_variants($slot));
}
$qa = $this->get_question_attempt($slot);
$qa->start($this->preferredbehaviour, $variant, array(), $timenow);
$this->observer->notify_attempt_modified($qa);
}
/**
* Start the attempt at all questions that has been added to this usage.
* @param question_variant_selection_strategy how to pick which variant of each question to use.
* @param int $timestamp optional, the timstamp to record for this action. Defaults to now.
* @param int $userid optional, the user to attribute this action to. Defaults to the current user.
*/
public function start_all_questions(question_variant_selection_strategy $variantstrategy = null,
$timestamp = null, $userid = null) {
if (is_null($variantstrategy)) {
$variantstrategy = new question_variant_random_strategy();
}
foreach ($this->questionattempts as $qa) {
$qa->start($this->preferredbehaviour, $qa->select_variant($variantstrategy), array(),
$timestamp, $userid);
$this->observer->notify_attempt_modified($qa);
}
}
/**
* Start the attempt at a question, starting from the point where the previous
* question_attempt $oldqa had reached. This is used by the quiz 'Each attempt
* builds on last' mode.
* @param int $slot the number used to identify this question within this usage.
* @param question_attempt $oldqa a previous attempt at this quetsion that
* defines the starting point.
*/
public function start_question_based_on($slot, question_attempt $oldqa) {
$qa = $this->get_question_attempt($slot);
$qa->start_based_on($oldqa);
$this->observer->notify_attempt_modified($qa);
}
/**
* Process all the question actions in the current request.
*
* If there is a parameter slots included in the post data, then only
* those question numbers will be processed, otherwise all questions in this
* useage will be.
*
* This function also does {@link update_question_flags()}.
*
* @param int $timestamp optional, use this timestamp as 'now'.
* @param array $postdata optional, only intended for testing. Use this data
* instead of the data from $_POST.
*/
public function process_all_actions($timestamp = null, $postdata = null) {
foreach ($this->get_slots_in_request($postdata) as $slot) {
if (!$this->validate_sequence_number($slot, $postdata)) {
continue;
}
$submitteddata = $this->extract_responses($slot, $postdata);
$this->process_action($slot, $submitteddata, $timestamp);
}
$this->update_question_flags($postdata);
}
/**
* Process all the question autosave data in the current request.
*
* If there is a parameter slots included in the post data, then only
* those question numbers will be processed, otherwise all questions in this
* useage will be.
*
* This function also does {@link update_question_flags()}.
*
* @param int $timestamp optional, use this timestamp as 'now'.
* @param array $postdata optional, only intended for testing. Use this data
* instead of the data from $_POST.
*/
public function process_all_autosaves($timestamp = null, $postdata = null) {
foreach ($this->get_slots_in_request($postdata) as $slot) {
if (!$this->is_autosave_required($slot, $postdata)) {
continue;
}
$submitteddata = $this->extract_responses($slot, $postdata);
$this->process_autosave($slot, $submitteddata, $timestamp);
}
$this->update_question_flags($postdata);
}
/**
* Get the list of slot numbers that should be processed as part of processing
* the current request.
* @param array $postdata optional, only intended for testing. Use this data
* instead of the data from $_POST.
* @return array of slot numbers.
*/
protected function get_slots_in_request($postdata = null) {
// Note: we must not use "question_attempt::get_submitted_var()" because there is no attempt instance!!!
if (is_null($postdata)) {
$slots = optional_param('slots', null, PARAM_SEQUENCE);
} else if (array_key_exists('slots', $postdata)) {
$slots = clean_param($postdata['slots'], PARAM_SEQUENCE);
} else {
$slots = null;
}
if (is_null($slots)) {
$slots = $this->get_slots();
} else if (!$slots) {
$slots = array();
} else {
$slots = explode(',', $slots);
}
return $slots;
}
/**
* Get the submitted data from the current request that belongs to this
* particular question.
*
* @param int $slot the number used to identify this question within this usage.
* @param array|null $postdata optional, only intended for testing. Use this data
* instead of the data from $_POST.
* @return array submitted data specific to this question.
*/
public function extract_responses($slot, $postdata = null) {
return $this->get_question_attempt($slot)->get_submitted_data($postdata);
}
/**
* Transform an array of response data for slots to an array of post data as you would get from quiz attempt form.
*
* @param $simulatedresponses array keys are slot nos => contains arrays representing student
* responses which will be passed to question_definition::prepare_simulated_post_data method
* and then have the appropriate prefix added.
* @return array simulated post data
*/
public function prepare_simulated_post_data($simulatedresponses) {
$simulatedpostdata = array();
$simulatedpostdata['slots'] = implode(',', array_keys($simulatedresponses));
foreach ($simulatedresponses as $slot => $responsedata) {
$slotresponse = array();
// Behaviour vars should not be processed by question type, just add prefix.
$behaviourvars = $this->get_question_attempt($slot)->get_behaviour()->get_expected_data();
foreach (array_keys($responsedata) as $responsedatakey) {
if (is_string($responsedatakey) && $responsedatakey[0] === '-') {
$behaviourvarname = substr($responsedatakey, 1);
if (isset($behaviourvars[$behaviourvarname])) {
// Expected behaviour var found.
if ($responsedata[$responsedatakey]) {
// Only set the behaviour var if the column value from the cvs file is non zero.
// The behaviours only look at whether the var is set or not they don't look at the value.
$slotresponse[$responsedatakey] = $responsedata[$responsedatakey];
}
}
// Remove both expected and unexpected vars from data passed to question type.
unset($responsedata[$responsedatakey]);
}
}
$slotresponse += $this->get_question($slot)->prepare_simulated_post_data($responsedata);
$slotresponse[':sequencecheck'] = $this->get_question_attempt($slot)->get_sequence_check_count();
// Add this slot's prefix to slot data.
$prefix = $this->get_field_prefix($slot);
foreach ($slotresponse as $key => $value) {
$simulatedpostdata[$prefix.$key] = $value;
}
}
return $simulatedpostdata;
}
/**
* Process a specific action on a specific question.
* @param int $slot the number used to identify this question within this usage.
* @param array $submitteddata the submitted data that constitutes the action.
* @param int|null $timestamp (optional) the timestamp to consider 'now'.
*/
public function process_action($slot, $submitteddata, $timestamp = null) {
$qa = $this->get_question_attempt($slot);
$qa->process_action($submitteddata, $timestamp);
$this->observer->notify_attempt_modified($qa);
}
/**
* Process an autosave action on a specific question.
* @param int $slot the number used to identify this question within this usage.
* @param array $submitteddata the submitted data that constitutes the action.
* @param int|null $timestamp (optional) the timestamp to consider 'now'.
*/
public function process_autosave($slot, $submitteddata, $timestamp = null) {
$qa = $this->get_question_attempt($slot);
if ($qa->process_autosave($submitteddata, $timestamp)) {
$this->observer->notify_attempt_modified($qa);
}
}
/**
* Check that the sequence number, that detects weird things like the student clicking back, is OK.
*
* If the sequence check variable is not present, returns
* false. If the check variable is present and correct, returns true. If the
* variable is present and wrong, throws an exception.
*
* @param int $slot the number used to identify this question within this usage.
* @param array|null $postdata (optional) data to use in place of $_POST.
* @return bool true if the check variable is present and correct. False if it
* is missing. (Throws an exception if the check fails.)
*/
public function validate_sequence_number($slot, $postdata = null) {
$qa = $this->get_question_attempt($slot);
$sequencecheck = $qa->get_submitted_var(
$qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
if (is_null($sequencecheck)) {
return false;
} else if ($sequencecheck != $qa->get_sequence_check_count()) {
throw new question_out_of_sequence_exception($this->id, $slot, $postdata);
} else {
return true;
}
}
/**
* Check, based on the sequence number, whether this auto-save is still required.
*
* @param int $slot the number used to identify this question within this usage.
* @param array|null $postdata the submitted data that constitutes the action.
* @return bool true if the check variable is present and correct, otherwise false.
*/
public function is_autosave_required($slot, $postdata = null) {
$qa = $this->get_question_attempt($slot);
$sequencecheck = $qa->get_submitted_var(
$qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
if (is_null($sequencecheck)) {
return false;
} else if ($sequencecheck != $qa->get_sequence_check_count()) {
return false;
} else {
return true;
}
}
/**
* Update the flagged state for all question_attempts in this usage, if their
* flagged state was changed in the request.
*
* @param array|null $postdata optional, only intended for testing. Use this data
* instead of the data from $_POST.
*/
public function update_question_flags($postdata = null) {
foreach ($this->questionattempts as $qa) {
$flagged = $qa->get_submitted_var(
$qa->get_flag_field_name(), PARAM_BOOL, $postdata);
if (!is_null($flagged) && $flagged != $qa->is_flagged()) {
$qa->set_flagged($flagged);
}
}
}
/**
* Get the correct response to a particular question. Passing the results of
* this method to {@link process_action()} will probably result in full marks.
* If it is not possible to compute a correct response, this method should return null.
* @param int $slot the number used to identify this question within this usage.
* @return array that constitutes a correct response to this question.
*/
public function get_correct_response($slot) {
return $this->get_question_attempt($slot)->get_correct_response();
}
/**
* Finish the active phase of an attempt at a question.
*
* This is an external act of finishing the attempt. Think, for example, of
* the 'Submit all and finish' button in the quiz. Some behaviours,
* (for example, immediatefeedback) give a way of finishing the active phase
* of a question attempt as part of a {@link process_action()} call.
*
* After the active phase is over, the only changes possible are things like
* manual grading, or changing the flag state.
*
* @param int $slot the number used to identify this question within this usage.
* @param int|null $timestamp (optional) the timestamp to consider 'now'.
*/
public function finish_question($slot, $timestamp = null) {
$qa = $this->get_question_attempt($slot);
$qa->finish($timestamp);
$this->observer->notify_attempt_modified($qa);
}
/**
* Finish the active phase of an attempt at a question. See {@link finish_question()}
* for a fuller description of what 'finish' means.
*
* @param int|null $timestamp (optional) the timestamp to consider 'now'.
*/
public function finish_all_questions($timestamp = null) {
foreach ($this->questionattempts as $qa) {
$qa->finish($timestamp);
$this->observer->notify_attempt_modified($qa);
}
}
/**
* Perform a manual grading action on a question attempt.
* @param int $slot the number used to identify this question within this usage.
* @param string $comment the comment being added to the question attempt.
* @param number $mark the mark that is being assigned. Can be null to just
* add a comment.
* @param int $commentformat one of the FORMAT_... constants. The format of $comment.
*/
public function manual_grade($slot, $comment, $mark, $commentformat = null) {
$qa = $this->get_question_attempt($slot);
$qa->manual_grade($comment, $mark, $commentformat);
$this->observer->notify_attempt_modified($qa);
}
/**
* Regrade a question in this usage. This replays the sequence of submitted
* actions to recompute the outcomes.
* @param int $slot the number used to identify this question within this usage.
* @param bool $finished whether the question attempt should be forced to be finished
* after the regrade, or whether it may still be in progress (default false).
* @param number $newmaxmark (optional) if given, will change the max mark while regrading.
*/
public function regrade_question($slot, $finished = false, $newmaxmark = null) {
$oldqa = $this->get_question_attempt($slot);
if (is_null($newmaxmark)) {
$newmaxmark = $oldqa->get_max_mark();
}
$newqa = new question_attempt($oldqa->get_question(), $oldqa->get_usage_id(),
$this->observer, $newmaxmark);
$newqa->set_database_id($oldqa->get_database_id());
$newqa->set_slot($oldqa->get_slot());
$newqa->regrade($oldqa, $finished);
$this->questionattempts[$slot] = $newqa;
$this->observer->notify_attempt_modified($newqa);
}
/**
* Regrade all the questions in this usage (without changing their max mark).
* @param bool $finished whether each question should be forced to be finished
* after the regrade, or whether it may still be in progress (default false).
*/
public function regrade_all_questions($finished = false) {
foreach ($this->questionattempts as $slot => $notused) {
$this->regrade_question($slot, $finished);
}
}
/**
* Change the max mark for this question_attempt.
* @param int $slot the slot number of the question of inerest.
* @param float $maxmark the new max mark.
*/
public function set_max_mark($slot, $maxmark) {
$this->get_question_attempt($slot)->set_max_mark($maxmark);
}
/**
* Create a question_usage_by_activity from records loaded from the database.
*
* For internal use only.
*
* @param Iterator $records Raw records loaded from the database.
* @param int $qubaid The id of the question usage we are loading.
* @return question_usage_by_activity The newly constructed usage.
*/
public static function load_from_records($records, $qubaid) {
$record = $records->current();
while ($record->qubaid != $qubaid) {
$records->next();
if (!$records->valid()) {
throw new coding_exception("Question usage {$qubaid} not found in the database.");
}
$record = $records->current();
}
$quba = new question_usage_by_activity($record->component,
context::instance_by_id($record->contextid, IGNORE_MISSING));
$quba->set_id_from_database($record->qubaid);
$quba->set_preferred_behaviour($record->preferredbehaviour);
$quba->observer = new question_engine_unit_of_work($quba);
// If slot is null then the current pointer in $records will not be
// advanced in the while loop below, and we get stuck in an infinite loop,
// since this method is supposed to always consume at least one record.
// Therefore, in this case, advance the record here.
if (is_null($record->slot)) {
$records->next();
}
while ($record && $record->qubaid == $qubaid && !is_null($record->slot)) {
$quba->questionattempts[$record->slot] =
question_attempt::load_from_records($records,
$record->questionattemptid, $quba->observer,
$quba->get_preferred_behaviour());
if ($records->valid()) {
$record = $records->current();
} else {
$record = false;
}
}
return $quba;
}
}
/**
* A class abstracting access to the {@link question_usage_by_activity::$questionattempts} array.
*
* This class snapshots the list of {@link question_attempts} to iterate over
* when it is created. If a question is added to the usage mid-iteration, it
* will now show up.
*
* To create an instance of this class, use
* {@link question_usage_by_activity::get_attempt_iterator()}
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_attempt_iterator implements Iterator, ArrayAccess {
/** @var question_usage_by_activity that we are iterating over. */
protected $quba;
/** @var array of slot numbers. */
protected $slots;
/**
* To create an instance of this class, use
* {@link question_usage_by_activity::get_attempt_iterator()}.
*
* @param question_usage_by_activity $quba the usage to iterate over.
*/
public function __construct(question_usage_by_activity $quba) {
$this->quba = $quba;
$this->slots = $quba->get_slots();
$this->rewind();
}
/**
* Standard part of the Iterator interface.
*
* @return question_attempt
*/
public function current() {
return $this->offsetGet(current($this->slots));
}
/**
* Standard part of the Iterator interface.
*
* @return int
*/
public function key() {
return current($this->slots);
}
/**
* Standard part of the Iterator interface.
*/
public function next() {
next($this->slots);
}
/**
* Standard part of the Iterator interface.
*/
public function rewind() {
reset($this->slots);
}
/**
* Standard part of the Iterator interface.
*
* @return bool
*/
public function valid() {
return current($this->slots) !== false;
}
/**
* Standard part of the ArrayAccess interface.
*
* @param int $slot
* @return bool
*/
public function offsetExists($slot) {
return in_array($slot, $this->slots);
}
/**
* Standard part of the ArrayAccess interface.
*
* @param int $slot
* @return question_attempt
*/
public function offsetGet($slot) {
return $this->quba->get_question_attempt($slot);
}
/**
* Standard part of the ArrayAccess interface.
*
* @param int $slot
* @param question_attempt $value
*/
public function offsetSet($slot, $value) {
throw new coding_exception('You are only allowed read-only access to ' .
'question_attempt::states through a question_attempt_step_iterator. Cannot set.');
}
/**
* Standard part of the ArrayAccess interface.
*
* @param int $slot
*/
public function offsetUnset($slot) {
throw new coding_exception('You are only allowed read-only access to ' .
'question_attempt::states through a question_attempt_step_iterator. Cannot unset.');
}
}
/**
* Interface for things that want to be notified of signficant changes to a
* {@link question_usage_by_activity}.
*
* A question behaviour controls the flow of actions a student can
* take as they work through a question, and later, as a teacher manually grades it.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
interface question_usage_observer {
/** Called when a field of the question_usage_by_activity is changed. */
public function notify_modified();
/**
* Called when a new question attempt is added to this usage.
* @param question_attempt $qa the newly added question attempt.
*/
public function notify_attempt_added(question_attempt $qa);
/**
* Called when the fields of a question attempt in this usage are modified.
* @param question_attempt $qa the newly added question attempt.
*/
public function notify_attempt_modified(question_attempt $qa);
/**
* Called when a question_attempt has been moved to a new slot.
* @param question_attempt $qa The question attempt that was moved.
* @param int $oldslot The previous slot number of that attempt.
*/
public function notify_attempt_moved(question_attempt $qa, $oldslot);
/**
* Called when a new step is added to a question attempt in this usage.
* @param question_attempt_step $step the new step.
* @param question_attempt $qa the usage it is being added to.
* @param int $seq the sequence number of the new step.
*/
public function notify_step_added(question_attempt_step $step, question_attempt $qa, $seq);
/**
* Called when a new step is updated in a question attempt in this usage.
* @param question_attempt_step $step the step that was updated.
* @param question_attempt $qa the usage it is being added to.
* @param int $seq the sequence number of the new step.
*/
public function notify_step_modified(question_attempt_step $step, question_attempt $qa, $seq);
/**
* Called when a new step is updated in a question attempt in this usage.
* @param question_attempt_step $step the step to delete.
* @param question_attempt $qa the usage it is being added to.
*/
public function notify_step_deleted(question_attempt_step $step, question_attempt $qa);
/**
* Called when a new metadata variable is set on a question attempt in this usage.
* @param question_attempt $qa the question attempt the metadata is being added to.
* @param int $name the name of the metadata variable added.
*/
public function notify_metadata_added(question_attempt $qa, $name);
/**
* Called when a metadata variable on a question attempt in this usage is updated.
* @param question_attempt $qa the question attempt where the metadata is being modified.
* @param int $name the name of the metadata variable modified.
*/
public function notify_metadata_modified(question_attempt $qa, $name);
}
/**
* Null implmentation of the {@link question_usage_watcher} interface.
* Does nothing.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_usage_null_observer implements question_usage_observer {
public function notify_modified() {
}
public function notify_attempt_added(question_attempt $qa) {
}
public function notify_attempt_modified(question_attempt $qa) {
}
public function notify_attempt_moved(question_attempt $qa, $oldslot) {
}
public function notify_step_added(question_attempt_step $step, question_attempt $qa, $seq) {
}
public function notify_step_modified(question_attempt_step $step, question_attempt $qa, $seq) {
}
public function notify_step_deleted(question_attempt_step $step, question_attempt $qa) {
}
public function notify_metadata_added(question_attempt $qa, $name) {
}
public function notify_metadata_modified(question_attempt $qa, $name) {
}
}