moodle/question/engine/questionattempt.php
Tim Hunt a8de866712 MDL-47740 question engine: let qs update variant later if appropriate
Variant has two purposes. First to determine which version of the
question the student will see. Hence it is used to set up the state
of the quetsion when the question is started. Then the internal state of
the question is saved in the first step.

Once that has been done, the variant number is purely informative, and
just used to break down the statistics.

In some cases (the one I have in mind is qtype_opaque) then there is a
complex randomisation process, which may lead to several inital variant
numbers acutally giving the same version of the question. In this case
it is nice if the question can update the stored variant number, to make
the statistics more meaningful.
2014-10-21 11:43:57 +01:00

1752 lines
65 KiB
PHP

<?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 attempt 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();
/**
* Tracks an attempt at one particular question in a {@link question_usage_by_activity}.
*
* Most calling code should need to access objects of this class. They should be
* able to do everything through the usage interface. This class is an internal
* implementation detail of the question engine.
*
* Instances of this class correspond to rows in the question_attempts table, and
* a collection of {@link question_attempt_steps}. Question inteaction models and
* question types do work with question_attempt objects.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_attempt {
/**
* @var string this is a magic value that question types can return from
* {@link question_definition::get_expected_data()}.
*/
const USE_RAW_DATA = 'use raw data';
/**
* @var string special value used by manual grading because {@link PARAM_FLOAT}
* converts '' to 0.
*/
const PARAM_MARK = 'parammark';
/**
* @var string special value to indicate a response variable that is uploaded
* files.
*/
const PARAM_FILES = 'paramfiles';
/**
* @var string special value to indicate a response variable that is uploaded
* files.
*/
const PARAM_RAW_FILES = 'paramrawfiles';
/**
* @var string means first try at a question during an attempt by a user.
*/
const FIRST_TRY = 'firsttry';
/**
* @var string means last try at a question during an attempt by a user.
*/
const LAST_TRY = 'lasttry';
/**
* @var string means all tries at a question during an attempt by a user.
*/
const ALL_TRIES = 'alltries';
/** @var integer if this attempts is stored in the question_attempts table, the id of that row. */
protected $id = null;
/** @var integer|string the id of the question_usage_by_activity we belong to. */
protected $usageid;
/** @var integer the number used to identify this question_attempt within the usage. */
protected $slot = null;
/**
* @var question_behaviour the behaviour controlling this attempt.
* null until {@link start()} is called.
*/
protected $behaviour = null;
/** @var question_definition the question this is an attempt at. */
protected $question;
/** @var int which variant of the question to use. */
protected $variant;
/**
* @var float the maximum mark that can be scored at this question.
* Actually, this is only really a nominal maximum. It might be better thought
* of as the question weight.
*/
protected $maxmark;
/**
* @var float the minimum fraction that can be scored at this question, so
* the minimum mark is $this->minfraction * $this->maxmark.
*/
protected $minfraction = null;
/**
* @var float the maximum fraction that can be scored at this question, so
* the maximum mark is $this->maxfraction * $this->maxmark.
*/
protected $maxfraction = null;
/**
* @var string plain text summary of the variant of the question the
* student saw. Intended for reporting purposes.
*/
protected $questionsummary = null;
/**
* @var string plain text summary of the response the student gave.
* Intended for reporting purposes.
*/
protected $responsesummary = null;
/**
* @var string plain text summary of the correct response to this question
* variant the student saw. The format should be similar to responsesummary.
* Intended for reporting purposes.
*/
protected $rightanswer = null;
/** @var array of {@link question_attempt_step}s. The steps in this attempt. */
protected $steps = array();
/**
* @var question_attempt_step if, when we loaded the step from the DB, there was
* an autosaved step, we save a pointer to it here. (It is also added to the $steps array.)
*/
protected $autosavedstep = null;
/** @var boolean whether the user has flagged this attempt within the usage. */
protected $flagged = false;
/** @var question_usage_observer tracks changes to the useage this attempt is part of.*/
protected $observer;
/**#@+
* Constants used by the intereaction models to indicate whether the current
* pending step should be kept or discarded.
*/
const KEEP = true;
const DISCARD = false;
/**#@-*/
/**
* Create a new {@link question_attempt}. Normally you should create question_attempts
* indirectly, by calling {@link question_usage_by_activity::add_question()}.
*
* @param question_definition $question the question this is an attempt at.
* @param int|string $usageid The id of the
* {@link question_usage_by_activity} we belong to. Used by {@link get_field_prefix()}.
* @param question_usage_observer $observer tracks changes to the useage this
* attempt is part of. (Optional, a {@link question_usage_null_observer} is
* used if one is not passed.
* @param number $maxmark the maximum grade for this question_attempt. If not
* passed, $question->defaultmark is used.
*/
public function __construct(question_definition $question, $usageid,
question_usage_observer $observer = null, $maxmark = null) {
$this->question = $question;
$this->usageid = $usageid;
if (is_null($observer)) {
$observer = new question_usage_null_observer();
}
$this->observer = $observer;
if (!is_null($maxmark)) {
$this->maxmark = $maxmark;
} else {
$this->maxmark = $question->defaultmark;
}
}
/**
* This method exists so that {@link question_attempt_with_restricted_history}
* can override it. You should not normally need to call it.
* @return question_attempt return ourself.
*/
public function get_full_qa() {
return $this;
}
/** @return question_definition the question this is an attempt at. */
public function get_question() {
return $this->question;
}
/**
* Get the variant of the question being used in a given slot.
* @return int the variant number.
*/
public function get_variant() {
return $this->variant;
}
/**
* Set the number used to identify this question_attempt within the usage.
* For internal use only.
* @param int $slot
*/
public function set_slot($slot) {
$this->slot = $slot;
}
/** @return int the number used to identify this question_attempt within the usage. */
public function get_slot() {
return $this->slot;
}
/**
* @return int the id of row for this question_attempt, if it is stored in the
* database. null if not.
*/
public function get_database_id() {
return $this->id;
}
/**
* For internal use only. Set the id of the corresponding database row.
* @param int $id the id of row for this question_attempt, if it is
* stored in the database.
*/
public function set_database_id($id) {
$this->id = $id;
}
/**
* You should almost certainly not call this method from your code. It is for
* internal use only.
* @param question_usage_observer that should be used to tracking changes made to this qa.
*/
public function set_observer($observer) {
$this->observer = $observer;
}
/** @return int|string the id of the {@link question_usage_by_activity} we belong to. */
public function get_usage_id() {
return $this->usageid;
}
/**
* Set the id of the {@link question_usage_by_activity} we belong to.
* For internal use only.
* @param int|string the new id.
*/
public function set_usage_id($usageid) {
$this->usageid = $usageid;
}
/** @return string the name of the behaviour that is controlling this attempt. */
public function get_behaviour_name() {
return $this->behaviour->get_name();
}
/**
* For internal use only.
* @return question_behaviour the behaviour that is controlling this attempt.
*/
public function get_behaviour() {
return $this->behaviour;
}
/**
* Set the flagged state of this question.
* @param bool $flagged the new state.
*/
public function set_flagged($flagged) {
$this->flagged = $flagged;
$this->observer->notify_attempt_modified($this);
}
/** @return bool whether this question is currently flagged. */
public function is_flagged() {
return $this->flagged;
}
/**
* Get the name (in the sense a HTML name="" attribute, or a $_POST variable
* name) to use for the field that indicates whether this question is flagged.
*
* @return string The field name to use.
*/
public function get_flag_field_name() {
return $this->get_control_field_name('flagged');
}
/**
* Get the name (in the sense a HTML name="" attribute, or a $_POST variable
* name) to use for a question_type variable belonging to this question_attempt.
*
* See the comment on {@link question_attempt_step} for an explanation of
* question type and behaviour variables.
*
* @param $varname The short form of the variable name.
* @return string The field name to use.
*/
public function get_qt_field_name($varname) {
return $this->get_field_prefix() . $varname;
}
/**
* Get the name (in the sense a HTML name="" attribute, or a $_POST variable
* name) to use for a question_type variable belonging to this question_attempt.
*
* See the comment on {@link question_attempt_step} for an explanation of
* question type and behaviour variables.
*
* @param $varname The short form of the variable name.
* @return string The field name to use.
*/
public function get_behaviour_field_name($varname) {
return $this->get_field_prefix() . '-' . $varname;
}
/**
* Get the name (in the sense a HTML name="" attribute, or a $_POST variable
* name) to use for a control variables belonging to this question_attempt.
*
* Examples are :sequencecheck and :flagged
*
* @param $varname The short form of the variable name.
* @return string The field name to use.
*/
public function get_control_field_name($varname) {
return $this->get_field_prefix() . ':' . $varname;
}
/**
* Get the prefix added to variable names to give field names for this
* question attempt.
*
* You should not use this method directly. This is an implementation detail
* anyway, but if you must access it, use {@link question_usage_by_activity::get_field_prefix()}.
*
* @param $varname The short form of the variable name.
* @return string The field name to use.
*/
public function get_field_prefix() {
return 'q' . $this->usageid . ':' . $this->slot . '_';
}
/**
* Get one of the steps in this attempt.
*
* @param int $i the step number.
* @return question_attempt_step
*/
public function get_step($i) {
if ($i < 0 || $i >= count($this->steps)) {
throw new coding_exception('Index out of bounds in question_attempt::get_step.');
}
return $this->steps[$i];
}
/**
* Get the number of real steps in this attempt.
* This is put as a hidden field in the HTML, so that when we receive some
* data to process, then we can check that it came from the question
* in the state we are now it.
* @return int a number that summarises the current state of this question attempt.
*/
public function get_sequence_check_count() {
$numrealsteps = $this->get_num_steps();
if ($this->has_autosaved_step()) {
$numrealsteps -= 1;
}
return $numrealsteps;
}
/**
* Get the number of steps in this attempt.
* For internal/test code use only.
* @return int the number of steps we currently have.
*/
public function get_num_steps() {
return count($this->steps);
}
/**
* Return the latest step in this question_attempt.
* For internal/test code use only.
* @return question_attempt_step
*/
public function get_last_step() {
if (count($this->steps) == 0) {
return new question_null_step();
}
return end($this->steps);
}
/**
* @return boolean whether this question_attempt has autosaved data from
* some time in the past.
*/
public function has_autosaved_step() {
return !is_null($this->autosavedstep);
}
/**
* @return question_attempt_step_iterator for iterating over the steps in
* this attempt, in order.
*/
public function get_step_iterator() {
return new question_attempt_step_iterator($this);
}
/**
* The same as {@link get_step_iterator()}. However, for a
* {@link question_attempt_with_restricted_history} this returns the full
* list of steps, while {@link get_step_iterator()} returns only the
* limited history.
* @return question_attempt_step_iterator for iterating over the steps in
* this attempt, in order.
*/
public function get_full_step_iterator() {
return $this->get_step_iterator();
}
/**
* @return question_attempt_reverse_step_iterator for iterating over the steps in
* this attempt, in reverse order.
*/
public function get_reverse_step_iterator() {
return new question_attempt_reverse_step_iterator($this);
}
/**
* Get the qt data from the latest step that has any qt data. Return $default
* array if it is no step has qt data.
*
* @param string $name the name of the variable to get.
* @param mixed default the value to return no step has qt data.
* (Optional, defaults to an empty array.)
* @return array|mixed the data, or $default if there is not any.
*/
public function get_last_qt_data($default = array()) {
foreach ($this->get_reverse_step_iterator() as $step) {
$response = $step->get_qt_data();
if (!empty($response)) {
return $response;
}
}
return $default;
}
/**
* Get the last step with a particular question type varialbe set.
* @param string $name the name of the variable to get.
* @return question_attempt_step the last step, or a step with no variables
* if there was not a real step.
*/
public function get_last_step_with_qt_var($name) {
foreach ($this->get_reverse_step_iterator() as $step) {
if ($step->has_qt_var($name)) {
return $step;
}
}
return new question_attempt_step_read_only();
}
/**
* Get the last step with a particular behaviour variable set.
* @param string $name the name of the variable to get.
* @return question_attempt_step the last step, or a step with no variables
* if there was not a real step.
*/
public function get_last_step_with_behaviour_var($name) {
foreach ($this->get_reverse_step_iterator() as $step) {
if ($step->has_behaviour_var($name)) {
return $step;
}
}
return new question_attempt_step_read_only();
}
/**
* Get the latest value of a particular question type variable. That is, get
* the value from the latest step that has it set. Return null if it is not
* set in any step.
*
* @param string $name the name of the variable to get.
* @param mixed default the value to return in the variable has never been set.
* (Optional, defaults to null.)
* @return mixed string value, or $default if it has never been set.
*/
public function get_last_qt_var($name, $default = null) {
$step = $this->get_last_step_with_qt_var($name);
if ($step->has_qt_var($name)) {
return $step->get_qt_var($name);
} else {
return $default;
}
}
/**
* Get the latest set of files for a particular question type variable of
* type question_attempt::PARAM_FILES.
*
* @param string $name the name of the associated variable.
* @return array of {@link stored_files}.
*/
public function get_last_qt_files($name, $contextid) {
foreach ($this->get_reverse_step_iterator() as $step) {
if ($step->has_qt_var($name)) {
return $step->get_qt_files($name, $contextid);
}
}
return array();
}
/**
* Get the URL of a file that belongs to a response variable of this
* question_attempt.
* @param stored_file $file the file to link to.
* @return string the URL of that file.
*/
public function get_response_file_url(stored_file $file) {
return file_encode_url(new moodle_url('/pluginfile.php'), '/' . implode('/', array(
$file->get_contextid(),
$file->get_component(),
$file->get_filearea(),
$this->usageid,
$this->slot,
$file->get_itemid())) .
$file->get_filepath() . $file->get_filename(), true);
}
/**
* Prepare a draft file are for the files belonging the a response variable
* of this question attempt. The draft area is populated with the files from
* the most recent step having files.
*
* @param string $name the variable name the files belong to.
* @param int $contextid the id of the context the quba belongs to.
* @return int the draft itemid.
*/
public function prepare_response_files_draft_itemid($name, $contextid) {
foreach ($this->get_reverse_step_iterator() as $step) {
if ($step->has_qt_var($name)) {
return $step->prepare_response_files_draft_itemid($name, $contextid);
}
}
// No files yet.
$draftid = 0; // Will be filled in by file_prepare_draft_area.
file_prepare_draft_area($draftid, $contextid, 'question', 'response_' . $name, null);
return $draftid;
}
/**
* Get the latest value of a particular behaviour variable. That is,
* get the value from the latest step that has it set. Return null if it is
* not set in any step.
*
* @param string $name the name of the variable to get.
* @param mixed default the value to return in the variable has never been set.
* (Optional, defaults to null.)
* @return mixed string value, or $default if it has never been set.
*/
public function get_last_behaviour_var($name, $default = null) {
foreach ($this->get_reverse_step_iterator() as $step) {
if ($step->has_behaviour_var($name)) {
return $step->get_behaviour_var($name);
}
}
return $default;
}
/**
* Get the current state of this question attempt. That is, the state of the
* latest step.
* @return question_state
*/
public function get_state() {
return $this->get_last_step()->get_state();
}
/**
* @param bool $showcorrectness Whether right/partial/wrong states should
* be distinguised.
* @return string A brief textual description of the current state.
*/
public function get_state_string($showcorrectness) {
// Special case when attempt is based on previous one, see MDL-31226.
if ($this->get_num_steps() == 1 && $this->get_state() == question_state::$complete) {
return get_string('notchanged', 'question');
}
return $this->behaviour->get_state_string($showcorrectness);
}
/**
* @param bool $showcorrectness Whether right/partial/wrong states should
* be distinguised.
* @return string a CSS class name for the current state.
*/
public function get_state_class($showcorrectness) {
return $this->get_state()->get_state_class($showcorrectness);
}
/**
* @return int the timestamp of the most recent step in this question attempt.
*/
public function get_last_action_time() {
return $this->get_last_step()->get_timecreated();
}
/**
* Get the current fraction of this question attempt. That is, the fraction
* of the latest step, or null if this question has not yet been graded.
* @return number the current fraction.
*/
public function get_fraction() {
return $this->get_last_step()->get_fraction();
}
/** @return bool whether this question attempt has a non-zero maximum mark. */
public function has_marks() {
// Since grades are stored in the database as NUMBER(12,7).
return $this->maxmark >= 0.00000005;
}
/**
* @return number the current mark for this question.
* {@link get_fraction()} * {@link get_max_mark()}.
*/
public function get_mark() {
return $this->fraction_to_mark($this->get_fraction());
}
/**
* This is used by the manual grading code, particularly in association with
* validation. If there is a mark submitted in the request, then use that,
* otherwise use the latest mark for this question.
* @return number the current mark for this question.
* {@link get_fraction()} * {@link get_max_mark()}.
*/
public function get_current_manual_mark() {
$mark = $this->get_submitted_var($this->get_behaviour_field_name('mark'), question_attempt::PARAM_MARK);
if (is_null($mark)) {
return $this->get_mark();
} else {
return $mark;
}
}
/**
* @param number|null $fraction a fraction.
* @return number|null the corresponding mark.
*/
public function fraction_to_mark($fraction) {
if (is_null($fraction)) {
return null;
}
return $fraction * $this->maxmark;
}
/**
* @return float the maximum mark possible for this question attempt.
* In fact, this is not strictly the maximum, becuase get_max_fraction may
* return a number greater than 1. It might be better to think of this as a
* question weight.
*/
public function get_max_mark() {
return $this->maxmark;
}
/** @return float the maximum mark possible for this question attempt. */
public function get_min_fraction() {
if (is_null($this->minfraction)) {
throw new coding_exception('This question_attempt has not been started yet, the min fraction is not yet known.');
}
return $this->minfraction;
}
/** @return float the maximum mark possible for this question attempt. */
public function get_max_fraction() {
if (is_null($this->maxfraction)) {
throw new coding_exception('This question_attempt has not been started yet, the max fraction is not yet known.');
}
return $this->maxfraction;
}
/**
* The current mark, formatted to the stated number of decimal places. Uses
* {@link format_float()} to format floats according to the current locale.
* @param int $dp number of decimal places.
* @return string formatted mark.
*/
public function format_mark($dp) {
return $this->format_fraction_as_mark($this->get_fraction(), $dp);
}
/**
* The current mark, formatted to the stated number of decimal places. Uses
* {@link format_float()} to format floats according to the current locale.
* @param int $dp number of decimal places.
* @return string formatted mark.
*/
public function format_fraction_as_mark($fraction, $dp) {
return format_float($this->fraction_to_mark($fraction), $dp);
}
/**
* The maximum mark for this question attempt, formatted to the stated number
* of decimal places. Uses {@link format_float()} to format floats according
* to the current locale.
* @param int $dp number of decimal places.
* @return string formatted maximum mark.
*/
public function format_max_mark($dp) {
return format_float($this->maxmark, $dp);
}
/**
* Return the hint that applies to the question in its current state, or null.
* @return question_hint|null
*/
public function get_applicable_hint() {
return $this->behaviour->get_applicable_hint();
}
/**
* Produce a plain-text summary of what the user did during a step.
* @param question_attempt_step $step the step in quetsion.
* @return string a summary of what was done during that step.
*/
public function summarise_action(question_attempt_step $step) {
return $this->behaviour->summarise_action($step);
}
/**
* Helper function used by {@link rewrite_pluginfile_urls()} and
* {@link rewrite_response_pluginfile_urls()}.
* @return array ids that need to go into the file paths.
*/
protected function extra_file_path_components() {
return array($this->get_usage_id(), $this->get_slot());
}
/**
* Calls {@link question_rewrite_question_urls()} with appropriate parameters
* for content belonging to this question.
* @param string $text the content to output.
* @param string $component the component name (normally 'question' or 'qtype_...')
* @param string $filearea the name of the file area.
* @param int $itemid the item id.
* @return srting the content with the URLs rewritten.
*/
public function rewrite_pluginfile_urls($text, $component, $filearea, $itemid) {
return question_rewrite_question_urls($text, 'pluginfile.php',
$this->question->contextid, $component, $filearea,
$this->extra_file_path_components(), $itemid);
}
/**
* Calls {@link question_rewrite_question_urls()} with appropriate parameters
* for content belonging to responses to this question.
*
* @param string $text the text to update the URLs in.
* @param int $contextid the id of the context the quba belongs to.
* @param string $name the variable name the files belong to.
* @param question_attempt_step $step the step the response is coming from.
* @return srting the content with the URLs rewritten.
*/
public function rewrite_response_pluginfile_urls($text, $contextid, $name,
question_attempt_step $step) {
return $step->rewrite_response_pluginfile_urls($text, $contextid, $name,
$this->extra_file_path_components());
}
/**
* 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 attempt in its current state.
* @param question_display_options $options controls how the question is rendered.
* @param string|null $number The question number to display.
* @return string HTML fragment representing the question.
*/
public function render($options, $number, $page = null) {
if (is_null($page)) {
global $PAGE;
$page = $PAGE;
}
$qoutput = $page->get_renderer('core', 'question');
$qtoutput = $this->question->get_renderer($page);
return $this->behaviour->render($options, $number, $qoutput, $qtoutput);
}
/**
* Generate any bits of HTML that needs to go in the <head> tag when this question
* attempt is displayed in the body.
* @return string HTML fragment.
*/
public function render_head_html($page = null) {
if (is_null($page)) {
global $PAGE;
$page = $PAGE;
}
// TODO go via behaviour.
return $this->question->get_renderer($page)->head_code($this) .
$this->behaviour->get_renderer($page)->head_code($this);
}
/**
* Like {@link render_question()} but displays the question at the past step
* indicated by $seq, rather than showing the latest step.
*
* @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 $number The question number to display. 'i' is a special
* value that gets displayed as Information. Null means no number is displayed.
* @return string HTML fragment representing the question.
*/
public function render_at_step($seq, $options, $number, $preferredbehaviour) {
$restrictedqa = new question_attempt_with_restricted_history($this, $seq, $preferredbehaviour);
return $restrictedqa->render($options, $number);
}
/**
* Checks whether the users is allow to be served a particular file.
* @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 $forcedownload whether the user must be forced to download the file.
* @return bool true if the user can access this file.
*/
public function check_file_access($options, $component, $filearea, $args, $forcedownload) {
return $this->behaviour->check_file_access($options, $component, $filearea, $args, $forcedownload);
}
/**
* Add a step to this question attempt.
* @param question_attempt_step $step the new step.
*/
protected function add_step(question_attempt_step $step) {
$this->steps[] = $step;
end($this->steps);
$this->observer->notify_step_added($step, $this, key($this->steps));
}
/**
* Add an auto-saved step to this question attempt. We mark auto-saved steps by
* changing saving the step number with a - sign.
* @param question_attempt_step $step the new step.
*/
protected function add_autosaved_step(question_attempt_step $step) {
$this->steps[] = $step;
$this->autosavedstep = $step;
end($this->steps);
$this->observer->notify_step_added($step, $this, -key($this->steps));
}
/**
* Discard any auto-saved data belonging to this question attempt.
*/
public function discard_autosaved_step() {
if (!$this->has_autosaved_step()) {
return;
}
$autosaved = array_pop($this->steps);
$this->autosavedstep = null;
$this->observer->notify_step_deleted($autosaved, $this);
}
/**
* If there is an autosaved step, convert it into a real save, so that it
* is preserved.
*/
protected function convert_autosaved_step_to_real_step() {
if ($this->autosavedstep === null) {
return;
}
$laststep = end($this->steps);
if ($laststep !== $this->autosavedstep) {
throw new coding_exception('Cannot convert autosaved step to real step, since other steps have been added.');
}
$this->observer->notify_step_modified($this->autosavedstep, $this, key($this->steps));
$this->autosavedstep = null;
}
/**
* Use a strategy to pick a variant.
* @param question_variant_selection_strategy $variantstrategy a strategy.
* @return int the selected variant.
*/
public function select_variant(question_variant_selection_strategy $variantstrategy) {
return $variantstrategy->choose_variant($this->get_question()->get_num_variants(),
$this->get_question()->get_variants_selection_seed());
}
/**
* Start this question attempt.
*
* You should not call this method directly. Call
* {@link question_usage_by_activity::start_question()} instead.
*
* @param string|question_behaviour $preferredbehaviour the name of the
* desired archetypal behaviour, or an actual model instance.
* @param int $variant the variant of the question to start. Between 1 and
* $this->get_question()->get_num_variants() inclusive.
* @param array $submitteddata optional, used when re-starting to keep the same initial state.
* @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.
* @param int $existingstepid optional, if this step is going to replace an existing step
* (for example, during a regrade) this is the id of the previous step we are replacing.
*/
public function start($preferredbehaviour, $variant, $submitteddata = array(),
$timestamp = null, $userid = null, $existingstepid = null) {
// Initialise the behaviour.
$this->variant = $variant;
if (is_string($preferredbehaviour)) {
$this->behaviour =
$this->question->make_behaviour($this, $preferredbehaviour);
} else {
$class = get_class($preferredbehaviour);
$this->behaviour = new $class($this, $preferredbehaviour);
}
// Record the minimum and maximum fractions.
$this->minfraction = $this->behaviour->get_min_fraction();
$this->maxfraction = $this->behaviour->get_max_fraction();
// Initialise the first step.
$firststep = new question_attempt_step($submitteddata, $timestamp, $userid, $existingstepid);
if ($submitteddata) {
$firststep->set_state(question_state::$complete);
$this->behaviour->apply_attempt_state($firststep);
} else {
$this->behaviour->init_first_step($firststep, $variant);
}
$this->add_step($firststep);
// Record questionline and correct answer.
$this->questionsummary = $this->behaviour->get_question_summary();
$this->rightanswer = $this->behaviour->get_right_answer_summary();
}
/**
* Start this question attempt, starting from the point that the previous
* attempt $oldqa had reached.
*
* You should not call this method directly. Call
* {@link question_usage_by_activity::start_question_based_on()} instead.
*
* @param question_attempt $oldqa a previous attempt at this quetsion that
* defines the starting point.
*/
public function start_based_on(question_attempt $oldqa) {
$this->start($oldqa->behaviour, $oldqa->get_variant(), $oldqa->get_resume_data());
}
/**
* Used by {@link start_based_on()} to get the data needed to start a new
* attempt from the point this attempt has go to.
* @return array name => value pairs.
*/
protected function get_resume_data() {
$resumedata = $this->behaviour->get_resume_data();
foreach ($resumedata as $name => $value) {
if ($value instanceof question_file_loader) {
$resumedata[$name] = $value->get_question_file_saver();
}
}
return $resumedata;
}
/**
* Get a particular parameter from the current request. A wrapper round
* {@link optional_param()}, except that the results is returned without
* slashes.
* @param string $name the paramter name.
* @param int $type one of the standard PARAM_... constants, or one of the
* special extra constands defined by this class.
* @param array $postdata (optional, only inteded for testing use) take the
* data from this array, instead of from $_POST.
* @return mixed the requested value.
*/
public function get_submitted_var($name, $type, $postdata = null) {
switch ($type) {
case self::PARAM_MARK:
// Special case to work around PARAM_FLOAT converting '' to 0.
return question_utils::clean_param_mark($this->get_submitted_var($name, PARAM_RAW_TRIMMED, $postdata));
case self::PARAM_FILES:
return $this->process_response_files($name, $name, $postdata);
case self::PARAM_RAW_FILES:
$var = $this->get_submitted_var($name, PARAM_RAW, $postdata);
return $this->process_response_files($name, $name . ':itemid', $postdata, $var);
default:
if (is_null($postdata)) {
$var = optional_param($name, null, $type);
} else if (array_key_exists($name, $postdata)) {
$var = clean_param($postdata[$name], $type);
} else {
$var = null;
}
return $var;
}
}
/**
* Handle a submitted variable representing uploaded files.
* @param string $name the field name.
* @param string $draftidname the field name holding the draft file area id.
* @param array $postdata (optional, only inteded for testing use) take the
* data from this array, instead of from $_POST. At the moment, this
* behaves as if there were no files.
* @param string $text optional reponse text.
* @return question_file_saver that can be used to save the files later.
*/
protected function process_response_files($name, $draftidname, $postdata = null, $text = null) {
if ($postdata) {
// For simulated posts, get the draft itemid from there.
$draftitemid = $this->get_submitted_var($draftidname, PARAM_INT, $postdata);
} else {
$draftitemid = file_get_submitted_draft_itemid($draftidname);
}
if (!$draftitemid) {
return null;
}
return new question_file_saver($draftitemid, 'question', 'response_' .
str_replace($this->get_field_prefix(), '', $name), $text);
}
/**
* Get any data from the request that matches the list of expected params.
* @param array $expected variable name => PARAM_... constant.
* @param string $extraprefix '-' or ''.
* @return array name => value.
*/
protected function get_expected_data($expected, $postdata, $extraprefix) {
$submitteddata = array();
foreach ($expected as $name => $type) {
$value = $this->get_submitted_var(
$this->get_field_prefix() . $extraprefix . $name, $type, $postdata);
if (!is_null($value)) {
$submitteddata[$extraprefix . $name] = $value;
}
}
return $submitteddata;
}
/**
* Get all the submitted question type data for this question, whithout checking
* that it is valid or cleaning it in any way.
* @return array name => value.
*/
public function get_all_submitted_qt_vars($postdata) {
if (is_null($postdata)) {
$postdata = $_POST;
}
$pattern = '/^' . preg_quote($this->get_field_prefix(), '/') . '[^-:]/';
$prefixlen = strlen($this->get_field_prefix());
$submitteddata = array();
foreach ($postdata as $name => $value) {
if (preg_match($pattern, $name)) {
$submitteddata[substr($name, $prefixlen)] = $value;
}
}
return $submitteddata;
}
/**
* Get all the sumbitted data belonging to this question attempt from the
* current request.
* @param array $postdata (optional, only inteded for testing use) take the
* data from this array, instead of from $_POST.
* @return array name => value pairs that could be passed to {@link process_action()}.
*/
public function get_submitted_data($postdata = null) {
$submitteddata = $this->get_expected_data(
$this->behaviour->get_expected_data(), $postdata, '-');
$expected = $this->behaviour->get_expected_qt_data();
if ($expected === self::USE_RAW_DATA) {
$submitteddata += $this->get_all_submitted_qt_vars($postdata);
} else {
$submitteddata += $this->get_expected_data($expected, $postdata, '');
}
return $submitteddata;
}
/**
* Get a set of response data for this question attempt that would get the
* best possible mark. If it is not possible to compute a correct
* response, this method should return null.
* @return array|null name => value pairs that could be passed to {@link process_action()}.
*/
public function get_correct_response() {
$response = $this->question->get_correct_response();
if (is_null($response)) {
return null;
}
$imvars = $this->behaviour->get_correct_response();
foreach ($imvars as $name => $value) {
$response['-' . $name] = $value;
}
return $response;
}
/**
* Change the quetsion summary. Note, that this is almost never necessary.
* This method was only added to work around a limitation of the Opaque
* protocol, which only sends questionLine at the end of an attempt.
* @param $questionsummary the new summary to set.
*/
public function set_question_summary($questionsummary) {
$this->questionsummary = $questionsummary;
$this->observer->notify_attempt_modified($this);
}
/**
* @return string a simple textual summary of the question that was asked.
*/
public function get_question_summary() {
return $this->questionsummary;
}
/**
* @return string a simple textual summary of response given.
*/
public function get_response_summary() {
return $this->responsesummary;
}
/**
* @return string a simple textual summary of the correct resonse.
*/
public function get_right_answer_summary() {
return $this->rightanswer;
}
/**
* Perform the action described by $submitteddata.
* @param array $submitteddata the submitted data the determines the action.
* @param int $timestamp the time to record for the action. (If not given, use now.)
* @param int $userid the user to attribute the action to. (If not given, use the current user.)
* @param int $existingstepid used by the regrade code.
*/
public function process_action($submitteddata, $timestamp = null, $userid = null, $existingstepid = null) {
$pendingstep = new question_attempt_pending_step($submitteddata, $timestamp, $userid, $existingstepid);
$this->discard_autosaved_step();
if ($this->behaviour->process_action($pendingstep) == self::KEEP) {
$this->add_step($pendingstep);
if ($pendingstep->response_summary_changed()) {
$this->responsesummary = $pendingstep->get_new_response_summary();
}
if ($pendingstep->variant_number_changed()) {
$this->variant = $pendingstep->get_new_variant_number();
}
}
}
/**
* Process an autosave.
* @param array $submitteddata the submitted data the determines the action.
* @param int $timestamp the time to record for the action. (If not given, use now.)
* @param int $userid the user to attribute the action to. (If not given, use the current user.)
* @return bool whether anything was saved.
*/
public function process_autosave($submitteddata, $timestamp = null, $userid = null) {
$pendingstep = new question_attempt_pending_step($submitteddata, $timestamp, $userid);
if ($this->behaviour->process_autosave($pendingstep) == self::KEEP) {
$this->add_autosaved_step($pendingstep);
return true;
}
return false;
}
/**
* Perform a finish action on this question attempt. This corresponds to an
* external finish action, for example the user pressing Submit all and finish
* in the quiz, rather than using one of the controls that is part of the
* question.
*
* @param int $timestamp the time to record for the action. (If not given, use now.)
* @param int $userid the user to attribute the aciton to. (If not given, use the current user.)
*/
public function finish($timestamp = null, $userid = null) {
$this->convert_autosaved_step_to_real_step();
$this->process_action(array('-finish' => 1), $timestamp, $userid);
}
/**
* Perform a regrade. This replays all the actions from $oldqa into this
* attempt.
* @param question_attempt $oldqa the attempt to regrade.
* @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).
*/
public function regrade(question_attempt $oldqa, $finished) {
$first = true;
foreach ($oldqa->get_step_iterator() as $step) {
$this->observer->notify_step_deleted($step, $this);
if ($first) {
// First step of the attempt.
$first = false;
$this->start($oldqa->behaviour, $oldqa->get_variant(), $step->get_all_data(),
$step->get_timecreated(), $step->get_user_id(), $step->get_id());
} else if ($step->has_behaviour_var('finish') && count($step->get_submitted_data()) > 1) {
// This case relates to MDL-32062. The upgrade code from 2.0
// generates attempts where the final submit of the question
// data, and the finish action, are in the same step. The system
// cannot cope with that, so convert the single old step into
// two new steps.
$submitteddata = $step->get_submitted_data();
unset($submitteddata['-finish']);
$this->process_action($submitteddata,
$step->get_timecreated(), $step->get_user_id(), $step->get_id());
$this->finish($step->get_timecreated(), $step->get_user_id());
} else {
// This is the normal case. Replay the next step of the attempt.
$this->process_action($step->get_submitted_data(),
$step->get_timecreated(), $step->get_user_id(), $step->get_id());
}
}
if ($finished) {
$this->finish();
}
}
/**
* Perform a manual grading action on this attempt.
* @param string $comment the comment being added.
* @param float $mark the new mark. If null, then only a comment is added.
* @param int $commentformat the FORMAT_... for $comment. Must be given.
* @param int $timestamp the time to record for the action. (If not given, use now.)
* @param int $userid the user to attribute the aciton to. (If not given, use the current user.)
*/
public function manual_grade($comment, $mark, $commentformat = null, $timestamp = null, $userid = null) {
$submitteddata = array('-comment' => $comment);
if (is_null($commentformat)) {
debugging('You should pass $commentformat to manual_grade.', DEBUG_DEVELOPER);
$commentformat = FORMAT_HTML;
}
$submitteddata['-commentformat'] = $commentformat;
if (!is_null($mark)) {
$submitteddata['-mark'] = $mark;
$submitteddata['-maxmark'] = $this->maxmark;
}
$this->process_action($submitteddata, $timestamp, $userid);
}
/** @return bool Whether this question attempt has had a manual comment added. */
public function has_manual_comment() {
foreach ($this->steps as $step) {
if ($step->has_behaviour_var('comment')) {
return true;
}
}
return false;
}
/**
* @return array(string, int) the most recent manual comment that was added
* to this question, and the FORMAT_... it is.
*/
public function get_manual_comment() {
foreach ($this->get_reverse_step_iterator() as $step) {
if ($step->has_behaviour_var('comment')) {
return array($step->get_behaviour_var('comment'),
$step->get_behaviour_var('commentformat'));
}
}
return array(null, null);
}
/**
* This is used by the manual grading code, particularly in association with
* validation. If there is a comment submitted in the request, then use that,
* otherwise use the latest comment for this question.
* @return number the current mark for this question.
* {@link get_fraction()} * {@link get_max_mark()}.
*/
public function get_current_manual_comment() {
$comment = $this->get_submitted_var($this->get_behaviour_field_name('comment'), PARAM_RAW);
if (is_null($comment)) {
return $this->get_manual_comment();
} else {
$commentformat = $this->get_submitted_var(
$this->get_behaviour_field_name('commentformat'), PARAM_INT);
if ($commentformat === null) {
$commentformat = FORMAT_HTML;
}
return array($comment, $commentformat);
}
}
/**
* Break down a student response by sub part and classification. See also {@link question::classify_response}.
* Used for response analysis.
*
* @param string $whichtries which tries to analyse for response analysis. Will be one of
* question_attempt::FIRST_TRY, LAST_TRY or ALL_TRIES.
* Defaults to question_attempt::LAST_TRY.
* @return (question_classified_response|array)[] If $whichtries is question_attempt::FIRST_TRY or LAST_TRY index is subpartid
* and values are question_classified_response instances.
* If $whichtries is question_attempt::ALL_TRIES then first key is submitted response no
* and the second key is subpartid.
*/
public function classify_response($whichtries = self::LAST_TRY) {
return $this->behaviour->classify_response($whichtries);
}
/**
* Create a question_attempt_step from records loaded from the database.
*
* For internal use only.
*
* @param Iterator $records Raw records loaded from the database.
* @param int $questionattemptid The id of the question_attempt to extract.
* @return question_attempt The newly constructed question_attempt.
*/
public static function load_from_records($records, $questionattemptid,
question_usage_observer $observer, $preferredbehaviour) {
$record = $records->current();
while ($record->questionattemptid != $questionattemptid) {
$record = $records->next();
if (!$records->valid()) {
throw new coding_exception("Question attempt {$questionattemptid} not found in the database.");
}
$record = $records->current();
}
try {
$question = question_bank::load_question($record->questionid);
} catch (Exception $e) {
// The question must have been deleted somehow. Create a missing
// question to use in its place.
$question = question_bank::get_qtype('missingtype')->make_deleted_instance(
$record->questionid, $record->maxmark + 0);
}
$qa = new question_attempt($question, $record->questionusageid,
null, $record->maxmark + 0);
$qa->set_database_id($record->questionattemptid);
$qa->set_slot($record->slot);
$qa->variant = $record->variant + 0;
$qa->minfraction = $record->minfraction + 0;
$qa->maxfraction = $record->maxfraction + 0;
$qa->set_flagged($record->flagged);
$qa->questionsummary = $record->questionsummary;
$qa->rightanswer = $record->rightanswer;
$qa->responsesummary = $record->responsesummary;
$qa->timemodified = $record->timemodified;
$qa->behaviour = question_engine::make_behaviour(
$record->behaviour, $qa, $preferredbehaviour);
$qa->observer = $observer;
// If attemptstepid is null (which should not happen, but has happened
// due to corrupt data, see MDL-34251) 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->attemptstepid)) {
$records->next();
}
$i = 0;
$autosavedstep = null;
$autosavedsequencenumber = null;
while ($record && $record->questionattemptid == $questionattemptid && !is_null($record->attemptstepid)) {
$sequencenumber = $record->sequencenumber;
$nextstep = question_attempt_step::load_from_records($records, $record->attemptstepid, $qa->get_question()->get_type_name());
if ($sequencenumber < 0) {
if (!$autosavedstep) {
$autosavedstep = $nextstep;
$autosavedsequencenumber = -$sequencenumber;
} else {
// Old redundant data. Mark it for deletion.
$qa->observer->notify_step_deleted($nextstep, $qa);
}
} else {
$qa->steps[$i] = $nextstep;
if ($i == 0) {
$question->apply_attempt_state($qa->steps[0]);
}
$i++;
}
if ($records->valid()) {
$record = $records->current();
} else {
$record = false;
}
}
if ($autosavedstep) {
if ($autosavedsequencenumber >= $i) {
$qa->autosavedstep = $autosavedstep;
$qa->steps[$i] = $qa->autosavedstep;
} else {
$qa->observer->notify_step_deleted($autosavedstep, $qa);
}
}
return $qa;
}
/**
* Allow access to steps with responses submitted by students for grading in a question attempt.
*
* @return question_attempt_steps_with_submitted_response_iterator to access all steps with submitted data for questions that
* allow multiple submissions that count towards grade, per attempt.
*/
public function get_steps_with_submitted_response_iterator() {
return new question_attempt_steps_with_submitted_response_iterator($this);
}
}
/**
* This subclass of question_attempt pretends that only part of the step history
* exists. It is used for rendering the question in past states.
*
* All methods that try to modify the question_attempt throw exceptions.
*
* @copyright 2010 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_attempt_with_restricted_history extends question_attempt {
/**
* @var question_attempt the underlying question_attempt.
*/
protected $baseqa;
/**
* Create a question_attempt_with_restricted_history
* @param question_attempt $baseqa The question_attempt to make a restricted version of.
* @param int $lastseq the index of the last step to include.
* @param string $preferredbehaviour the preferred behaviour. It is slightly
* annoyting that this needs to be passed, but unavoidable for now.
*/
public function __construct(question_attempt $baseqa, $lastseq, $preferredbehaviour) {
$this->baseqa = $baseqa->get_full_qa();
if ($lastseq < 0 || $lastseq >= $this->baseqa->get_num_steps()) {
throw new coding_exception('$lastseq out of range', $lastseq);
}
$this->steps = array_slice($this->baseqa->steps, 0, $lastseq + 1);
$this->observer = new question_usage_null_observer();
// This should be a straight copy of all the remaining fields.
$this->id = $this->baseqa->id;
$this->usageid = $this->baseqa->usageid;
$this->slot = $this->baseqa->slot;
$this->question = $this->baseqa->question;
$this->maxmark = $this->baseqa->maxmark;
$this->minfraction = $this->baseqa->minfraction;
$this->maxfraction = $this->baseqa->maxfraction;
$this->questionsummary = $this->baseqa->questionsummary;
$this->responsesummary = $this->baseqa->responsesummary;
$this->rightanswer = $this->baseqa->rightanswer;
$this->flagged = $this->baseqa->flagged;
// Except behaviour, where we need to create a new one.
$this->behaviour = question_engine::make_behaviour(
$this->baseqa->get_behaviour_name(), $this, $preferredbehaviour);
}
public function get_full_qa() {
return $this->baseqa;
}
public function get_full_step_iterator() {
return $this->baseqa->get_step_iterator();
}
protected function add_step(question_attempt_step $step) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function process_action($submitteddata, $timestamp = null, $userid = null, $existingstepid = null) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function start($preferredbehaviour, $variant, $submitteddata = array(), $timestamp = null, $userid = null, $existingstepid = null) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function set_database_id($id) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function set_flagged($flagged) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function set_slot($slot) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function set_question_summary($questionsummary) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
public function set_usage_id($usageid) {
coding_exception('Cannot modify a question_attempt_with_restricted_history.');
}
}
/**
* A class abstracting access to the {@link question_attempt::$states} array.
*
* This is actively linked to question_attempt. If you add an new step
* mid-iteration, then it will be included.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_attempt_step_iterator implements Iterator, ArrayAccess {
/** @var question_attempt the question_attempt being iterated over. */
protected $qa;
/** @var integer records the current position in the iteration. */
protected $i;
/**
* Do not call this constructor directly.
* Use {@link question_attempt::get_step_iterator()}.
* @param question_attempt $qa the attempt to iterate over.
*/
public function __construct(question_attempt $qa) {
$this->qa = $qa;
$this->rewind();
}
/** @return question_attempt_step */
public function current() {
return $this->offsetGet($this->i);
}
/** @return int */
public function key() {
return $this->i;
}
public function next() {
++$this->i;
}
public function rewind() {
$this->i = 0;
}
/** @return bool */
public function valid() {
return $this->offsetExists($this->i);
}
/** @return bool */
public function offsetExists($i) {
return $i >= 0 && $i < $this->qa->get_num_steps();
}
/** @return question_attempt_step */
public function offsetGet($i) {
return $this->qa->get_step($i);
}
public function offsetSet($offset, $value) {
throw new coding_exception('You are only allowed read-only access to question_attempt::states through a question_attempt_step_iterator. Cannot set.');
}
public function offsetUnset($offset) {
throw new coding_exception('You are only allowed read-only access to question_attempt::states through a question_attempt_step_iterator. Cannot unset.');
}
}
/**
* A variant of {@link question_attempt_step_iterator} that iterates through the
* steps in reverse order.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_attempt_reverse_step_iterator extends question_attempt_step_iterator {
public function next() {
--$this->i;
}
public function rewind() {
$this->i = $this->qa->get_num_steps() - 1;
}
}
/**
* A variant of {@link question_attempt_step_iterator} that iterates through the
* steps with submitted tries.
*
* @copyright 2014 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_attempt_steps_with_submitted_response_iterator extends question_attempt_step_iterator implements Countable {
/** @var question_attempt the question_attempt being iterated over. */
protected $qa;
/** @var integer records the current position in the iteration. */
protected $submittedresponseno;
/**
* Index is the submitted response number and value is the step no.
*
* @var int[]
*/
protected $stepswithsubmittedresponses;
/**
* Do not call this constructor directly.
* Use {@link question_attempt::get_submission_step_iterator()}.
* @param question_attempt $qa the attempt to iterate over.
*/
public function __construct(question_attempt $qa) {
$this->qa = $qa;
$this->find_steps_with_submitted_response();
$this->rewind();
}
/**
* Find the step nos in which a student has submitted a response. Including any step with a response that is saved before
* the question attempt finishes.
*
* Called from constructor, should not be called from elsewhere.
*
*/
protected function find_steps_with_submitted_response() {
$stepnos = array();
$lastsavedstep = null;
foreach ($this->qa->get_step_iterator() as $stepno => $step) {
if ($this->qa->get_behaviour()->step_has_a_submitted_response($step)) {
$stepnos[] = $stepno;
$lastsavedstep = null;
} else {
$qtdata = $step->get_qt_data();
if (count($qtdata)) {
$lastsavedstep = $stepno;
}
}
}
if (!is_null($lastsavedstep)) {
$stepnos[] = $lastsavedstep;
}
if (empty($stepnos)) {
$this->stepswithsubmittedresponses = array();
} else {
// Re-index array so index starts with 1.
$this->stepswithsubmittedresponses = array_combine(range(1, count($stepnos)), $stepnos);
}
}
/** @return question_attempt_step */
public function current() {
return $this->offsetGet($this->submittedresponseno);
}
/** @return int */
public function key() {
return $this->submittedresponseno;
}
public function next() {
++$this->submittedresponseno;
}
public function rewind() {
$this->submittedresponseno = 1;
}
/** @return bool */
public function valid() {
return $this->submittedresponseno >= 1 && $this->submittedresponseno <= count($this->stepswithsubmittedresponses);
}
/**
* @param int $submittedresponseno
* @return bool
*/
public function offsetExists($submittedresponseno) {
return $submittedresponseno >= 1;
}
/**
* @param int $submittedresponseno
* @return question_attempt_step
*/
public function offsetGet($submittedresponseno) {
if ($submittedresponseno > count($this->stepswithsubmittedresponses)) {
return null;
} else {
return $this->qa->get_step($this->step_no_for_try($submittedresponseno));
}
}
/**
* @return int the count of steps with tries.
*/
public function count() {
return count($this->stepswithsubmittedresponses);
}
/**
* @param int $submittedresponseno
* @throws coding_exception
* @return int|null the step number or null if there is no such submitted response.
*/
public function step_no_for_try($submittedresponseno) {
if (isset($this->stepswithsubmittedresponses[$submittedresponseno])) {
return $this->stepswithsubmittedresponses[$submittedresponseno];
} else if ($submittedresponseno > count($this->stepswithsubmittedresponses)) {
return null;
} else {
throw new coding_exception('Try number not found. It should be 1 or more.');
}
}
public function offsetSet($offset, $value) {
throw new coding_exception('You are only allowed read-only access to question_attempt::states '.
'through a question_attempt_step_iterator. Cannot set.');
}
public function offsetUnset($offset) {
throw new coding_exception('You are only allowed read-only access to question_attempt::states '.
'through a question_attempt_step_iterator. Cannot unset.');
}
}