MDL-38538 question unit tests: improve things a bit.
[moodle.git] / question / engine / questionusage.php
CommitLineData
dcd03928 1<?php
dcd03928
TH
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * This file defines the question usage class, and a few related classes.
19 *
20 * @package moodlecore
21 * @subpackage questionengine
22 * @copyright 2009 The Open University
23 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
24 */
25
26
27defined('MOODLE_INTERNAL') || die();
28
29
30/**
31 * This class keeps track of a group of questions that are being attempted,
32 * and which state, and so on, each one is currently in.
33 *
34 * A quiz attempt or a lesson attempt could use an instance of this class to
35 * keep track of all the questions in the attempt and process student submissions.
36 * It is basically a collection of {@question_attempt} objects.
37 *
38 * The questions being attempted as part of this usage are identified by an integer
39 * that is passed into many of the methods as $slot. ($question->id is not
40 * used so that the same question can be used more than once in an attempt.)
41 *
42 * Normally, calling code should be able to do everything it needs to be calling
43 * methods of this class. You should not normally need to get individual
44 * {@question_attempt} objects and play around with their inner workind, in code
45 * that it outside the quetsion engine.
46 *
47 * Instances of this class correspond to rows in the question_usages table.
48 *
49 * @copyright 2009 The Open University
50 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
51 */
52class question_usage_by_activity {
53 /**
54 * @var integer|string the id for this usage. If this usage was loaded from
55 * the database, then this is the database id. Otherwise a unique random
56 * string is used.
57 */
58 protected $id = null;
59
60 /**
61 * @var string name of an archetypal behaviour, that should be used
62 * by questions in this usage if possible.
63 */
64 protected $preferredbehaviour = null;
65
4c16e191 66 /** @var context the context this usage belongs to. */
dcd03928
TH
67 protected $context;
68
69 /** @var string plugin name of the plugin this usage belongs to. */
70 protected $owningcomponent;
71
72 /** @var array {@link question_attempt}s that make up this usage. */
73 protected $questionattempts = array();
74
75 /** @var question_usage_observer that tracks changes to this usage. */
76 protected $observer;
77
78 /**
79 * Create a new instance. Normally, calling code should use
80 * {@link question_engine::make_questions_usage_by_activity()} or
81 * {@link question_engine::load_questions_usage_by_activity()} rather than
82 * calling this constructor directly.
83 *
84 * @param string $component the plugin creating this attempt. For example mod_quiz.
85 * @param object $context the context this usage belongs to.
86 */
87 public function __construct($component, $context) {
88 $this->owningcomponent = $component;
89 $this->context = $context;
90 $this->observer = new question_usage_null_observer();
91 }
92
93 /**
94 * @param string $behaviour the name of an archetypal behaviour, that should
95 * be used by questions in this usage if possible.
96 */
97 public function set_preferred_behaviour($behaviour) {
98 $this->preferredbehaviour = $behaviour;
99 $this->observer->notify_modified();
100 }
101
102 /** @return string the name of the preferred behaviour. */
103 public function get_preferred_behaviour() {
104 return $this->preferredbehaviour;
105 }
106
4c16e191 107 /** @return context the context this usage belongs to. */
dcd03928
TH
108 public function get_owning_context() {
109 return $this->context;
110 }
111
112 /** @return string the name of the plugin that owns this attempt. */
113 public function get_owning_component() {
114 return $this->owningcomponent;
115 }
116
117 /** @return int|string If this usage came from the database, then the id
118 * from the question_usages table is returned. Otherwise a random string is
119 * returned. */
120 public function get_id() {
121 if (is_null($this->id)) {
122 $this->id = random_string(10);
123 }
124 return $this->id;
125 }
126
dcd03928
TH
127 /**
128 * For internal use only. Used by {@link question_engine_data_mapper} to set
129 * the id when a usage is saved to the database.
130 * @param int $id the newly determined id for this usage.
131 */
132 public function set_id_from_database($id) {
133 $this->id = $id;
134 foreach ($this->questionattempts as $qa) {
135 $qa->set_usage_id($id);
136 }
137 }
138
94815ccf
TH
139 /** @return question_usage_observer that is tracking changes made to this usage. */
140 public function get_observer() {
141 return $this->observer;
142 }
143
144 /**
145 * You should almost certainly not call this method from your code. It is for
146 * internal use only.
147 * @param question_usage_observer that should be used to tracking changes made to this usage.
148 */
149 public function set_observer($observer) {
150 $this->observer = $observer;
151 foreach ($this->questionattempts as $qa) {
152 $qa->set_observer($observer);
153 }
154 }
155
dcd03928
TH
156 /**
157 * Add another question to this usage.
158 *
159 * The added question is not started until you call {@link start_question()}
160 * on it.
161 *
162 * @param question_definition $question the question to add.
163 * @param number $maxmark the maximum this question will be marked out of in
164 * this attempt (optional). If not given, $question->defaultmark is used.
165 * @return int the number used to identify this question within this usage.
166 */
167 public function add_question(question_definition $question, $maxmark = null) {
168 $qa = new question_attempt($question, $this->get_id(), $this->observer, $maxmark);
169 if (count($this->questionattempts) == 0) {
170 $this->questionattempts[1] = $qa;
171 } else {
172 $this->questionattempts[] = $qa;
173 }
b9832f2b
TH
174 end($this->questionattempts); // Ready to get the last key on the next line.
175 $qa->set_slot(key($this->questionattempts));
dcd03928
TH
176 $this->observer->notify_attempt_added($qa);
177 return $qa->get_slot();
178 }
179
180 /**
181 * Get the question_definition for a question in this attempt.
182 * @param int $slot the number used to identify this question within this usage.
183 * @return question_definition the requested question object.
184 */
185 public function get_question($slot) {
186 return $this->get_question_attempt($slot)->get_question();
187 }
188
189 /** @return array all the identifying numbers of all the questions in this usage. */
190 public function get_slots() {
191 return array_keys($this->questionattempts);
192 }
193
194 /** @return int the identifying number of the first question that was added to this usage. */
195 public function get_first_question_number() {
196 reset($this->questionattempts);
197 return key($this->questionattempts);
198 }
199
200 /** @return int the number of questions that are currently in this usage. */
201 public function question_count() {
202 return count($this->questionattempts);
203 }
204
205 /**
206 * Note the part of the {@link question_usage_by_activity} comment that explains
207 * that {@link question_attempt} objects should be considered part of the inner
208 * workings of the question engine, and should not, if possible, be accessed directly.
209 *
210 * @return question_attempt_iterator for iterating over all the questions being
211 * attempted. as part of this usage.
212 */
213 public function get_attempt_iterator() {
214 return new question_attempt_iterator($this);
215 }
216
217 /**
218 * Check whether $number actually corresponds to a question attempt that is
219 * part of this usage. Throws an exception if not.
220 *
221 * @param int $slot a number allegedly identifying a question within this usage.
222 */
223 protected function check_slot($slot) {
224 if (!array_key_exists($slot, $this->questionattempts)) {
9c197f44
TH
225 throw new coding_exception('There is no question_attempt number ' . $slot .
226 ' in this attempt.');
dcd03928
TH
227 }
228 }
229
230 /**
231 * Note the part of the {@link question_usage_by_activity} comment that explains
232 * that {@link question_attempt} objects should be considered part of the inner
233 * workings of the question engine, and should not, if possible, be accessed directly.
234 *
235 * @param int $slot the number used to identify this question within this usage.
236 * @return question_attempt the corresponding {@link question_attempt} object.
237 */
238 public function get_question_attempt($slot) {
239 $this->check_slot($slot);
240 return $this->questionattempts[$slot];
241 }
242
243 /**
244 * Get the current state of the attempt at a question.
245 * @param int $slot the number used to identify this question within this usage.
246 * @return question_state.
247 */
248 public function get_question_state($slot) {
249 return $this->get_question_attempt($slot)->get_state();
250 }
251
252 /**
253 * @param int $slot the number used to identify this question within this usage.
254 * @param bool $showcorrectness Whether right/partial/wrong states should
255 * be distinguised.
256 * @return string A brief textual description of the current state.
257 */
258 public function get_question_state_string($slot, $showcorrectness) {
259 return $this->get_question_attempt($slot)->get_state_string($showcorrectness);
260 }
261
97cdc1de
TH
262 /**
263 * @param int $slot the number used to identify this question within this usage.
264 * @param bool $showcorrectness Whether right/partial/wrong states should
265 * be distinguised.
266 * @return string a CSS class name for the current state.
267 */
268 public function get_question_state_class($slot, $showcorrectness) {
269 return $this->get_question_attempt($slot)->get_state_class($showcorrectness);
270 }
271
dcd03928
TH
272 /**
273 * Get the time of the most recent action performed on a question.
274 * @param int $slot the number used to identify this question within this usage.
275 * @return int timestamp.
276 */
277 public function get_question_action_time($slot) {
278 return $this->get_question_attempt($slot)->get_last_action_time();
279 }
280
281 /**
282 * Get the current fraction awarded for the attempt at a question.
283 * @param int $slot the number used to identify this question within this usage.
284 * @return number|null The current fraction for this question, or null if one has
285 * not been assigned yet.
286 */
287 public function get_question_fraction($slot) {
288 return $this->get_question_attempt($slot)->get_fraction();
289 }
290
291 /**
292 * Get the current mark awarded for the attempt at a question.
293 * @param int $slot the number used to identify this question within this usage.
294 * @return number|null The current mark for this question, or null if one has
295 * not been assigned yet.
296 */
297 public function get_question_mark($slot) {
298 return $this->get_question_attempt($slot)->get_mark();
299 }
300
301 /**
302 * Get the maximum mark possible for the attempt at a question.
303 * @param int $slot the number used to identify this question within this usage.
304 * @return number the available marks for this question.
305 */
306 public function get_question_max_mark($slot) {
307 return $this->get_question_attempt($slot)->get_max_mark();
308 }
309
310 /**
311 * Get the current mark awarded for the attempt at a question.
312 * @param int $slot the number used to identify this question within this usage.
313 * @return number|null The current mark for this question, or null if one has
314 * not been assigned yet.
315 */
316 public function get_total_mark() {
317 $mark = 0;
318 foreach ($this->questionattempts as $qa) {
319 if ($qa->get_max_mark() > 0 && $qa->get_state() == question_state::$needsgrading) {
320 return null;
321 }
322 $mark += $qa->get_mark();
323 }
324 return $mark;
325 }
326
327 /**
328 * @return string a simple textual summary of the question that was asked.
329 */
330 public function get_question_summary($slot) {
331 return $this->get_question_attempt($slot)->get_question_summary();
332 }
333
334 /**
335 * @return string a simple textual summary of response given.
336 */
337 public function get_response_summary($slot) {
338 return $this->get_question_attempt($slot)->get_response_summary();
339 }
340
341 /**
342 * @return string a simple textual summary of the correct resonse.
343 */
344 public function get_right_answer_summary($slot) {
345 return $this->get_question_attempt($slot)->get_right_answer_summary();
346 }
347
348 /**
349 * Get the {@link core_question_renderer}, in collaboration with appropriate
350 * {@link qbehaviour_renderer} and {@link qtype_renderer} subclasses, to generate the
351 * HTML to display this question.
352 * @param int $slot the number used to identify this question within this usage.
353 * @param question_display_options $options controls how the question is rendered.
354 * @param string|null $number The question number to display. 'i' is a special
355 * value that gets displayed as Information. Null means no number is displayed.
356 * @return string HTML fragment representing the question.
357 */
358 public function render_question($slot, $options, $number = null) {
359 $options->context = $this->context;
360 return $this->get_question_attempt($slot)->render($options, $number);
361 }
362
363 /**
364 * Generate any bits of HTML that needs to go in the <head> tag when this question
365 * is displayed in the body.
366 * @param int $slot the number used to identify this question within this usage.
367 * @return string HTML fragment.
368 */
369 public function render_question_head_html($slot) {
92701024 370 //$options->context = $this->context;
dcd03928
TH
371 return $this->get_question_attempt($slot)->render_head_html();
372 }
373
374 /**
375 * Like {@link render_question()} but displays the question at the past step
376 * indicated by $seq, rather than showing the latest step.
377 *
378 * @param int $slot the number used to identify this question within this usage.
379 * @param int $seq the seq number of the past state to display.
380 * @param question_display_options $options controls how the question is rendered.
381 * @param string|null $number The question number to display. 'i' is a special
382 * value that gets displayed as Information. Null means no number is displayed.
383 * @return string HTML fragment representing the question.
384 */
385 public function render_question_at_step($slot, $seq, $options, $number = null) {
386 $options->context = $this->context;
9c197f44
TH
387 return $this->get_question_attempt($slot)->render_at_step(
388 $seq, $options, $number, $this->preferredbehaviour);
dcd03928
TH
389 }
390
391 /**
392 * Checks whether the users is allow to be served a particular file.
393 * @param int $slot the number used to identify this question within this usage.
394 * @param question_display_options $options the options that control display of the question.
395 * @param string $component the name of the component we are serving files for.
396 * @param string $filearea the name of the file area.
397 * @param array $args the remaining bits of the file path.
398 * @param bool $forcedownload whether the user must be forced to download the file.
399 * @return bool true if the user can access this file.
400 */
9c197f44
TH
401 public function check_file_access($slot, $options, $component, $filearea,
402 $args, $forcedownload) {
403 return $this->get_question_attempt($slot)->check_file_access(
404 $options, $component, $filearea, $args, $forcedownload);
dcd03928
TH
405 }
406
407 /**
408 * Replace a particular question_attempt with a different one.
409 *
410 * For internal use only. Used when reloading the state of a question from the
411 * database.
412 *
413 * @param array $records Raw records loaded from the database.
414 * @param int $questionattemptid The id of the question_attempt to extract.
415 * @return question_attempt The newly constructed question_attempt_step.
416 */
417 public function replace_loaded_question_attempt_info($slot, $qa) {
418 $this->check_slot($slot);
419 $this->questionattempts[$slot] = $qa;
420 }
421
422 /**
423 * You should probably not use this method in code outside the question engine.
424 * The main reason for exposing it was for the benefit of unit tests.
425 * @param int $slot the number used to identify this question within this usage.
426 * @return string return the prefix that is pre-pended to field names in the HTML
427 * that is output.
428 */
429 public function get_field_prefix($slot) {
430 return $this->get_question_attempt($slot)->get_field_prefix();
431 }
432
1da821bb
TH
433 /**
434 * Get the number of variants available for the question in this slot.
435 * @param int $slot the number used to identify this question within this usage.
436 * @return int the number of variants available.
437 */
438 public function get_num_variants($slot) {
439 return $this->get_question_attempt($slot)->get_question()->get_num_variants();
440 }
441
442 /**
443 * Get the variant of the question being used in a given slot.
444 * @param int $slot the number used to identify this question within this usage.
445 * @return int the variant of this question that is being used.
446 */
447 public function get_variant($slot) {
448 return $this->get_question_attempt($slot)->get_variant();
449 }
450
dcd03928
TH
451 /**
452 * Start the attempt at a question that has been added to this usage.
453 * @param int $slot the number used to identify this question within this usage.
1da821bb
TH
454 * @param int $variant which variant of the question to use. Must be between
455 * 1 and ->get_num_variants($slot) inclusive. If not give, a variant is
456 * chosen at random.
dcd03928 457 */
1da821bb
TH
458 public function start_question($slot, $variant = null) {
459 if (is_null($variant)) {
460 $variant = rand(1, $this->get_num_variants($slot));
461 }
462
dcd03928 463 $qa = $this->get_question_attempt($slot);
1da821bb 464 $qa->start($this->preferredbehaviour, $variant);
dcd03928
TH
465 $this->observer->notify_attempt_modified($qa);
466 }
467
468 /**
469 * Start the attempt at all questions that has been added to this usage.
1da821bb 470 * @param question_variant_selection_strategy how to pick which variant of each question to use.
e35ba43c
TH
471 * @param int $timestamp optional, the timstamp to record for this action. Defaults to now.
472 * @param int $userid optional, the user to attribute this action to. Defaults to the current user.
dcd03928 473 */
1da821bb
TH
474 public function start_all_questions(question_variant_selection_strategy $variantstrategy = null,
475 $timestamp = null, $userid = null) {
476 if (is_null($variantstrategy)) {
477 $variantstrategy = new question_variant_random_strategy();
478 }
479
dcd03928 480 foreach ($this->questionattempts as $qa) {
1da821bb 481 $qa->start($this->preferredbehaviour, $qa->select_variant($variantstrategy));
dcd03928
TH
482 $this->observer->notify_attempt_modified($qa);
483 }
484 }
485
486 /**
487 * Start the attempt at a question, starting from the point where the previous
488 * question_attempt $oldqa had reached. This is used by the quiz 'Each attempt
489 * builds on last' mode.
490 * @param int $slot the number used to identify this question within this usage.
491 * @param question_attempt $oldqa a previous attempt at this quetsion that
492 * defines the starting point.
493 */
494 public function start_question_based_on($slot, question_attempt $oldqa) {
495 $qa = $this->get_question_attempt($slot);
496 $qa->start_based_on($oldqa);
497 $this->observer->notify_attempt_modified($qa);
498 }
499
500 /**
501 * Process all the question actions in the current request.
502 *
503 * If there is a parameter slots included in the post data, then only
504 * those question numbers will be processed, otherwise all questions in this
505 * useage will be.
506 *
507 * This function also does {@link update_question_flags()}.
508 *
509 * @param int $timestamp optional, use this timestamp as 'now'.
510 * @param array $postdata optional, only intended for testing. Use this data
511 * instead of the data from $_POST.
512 */
513 public function process_all_actions($timestamp = null, $postdata = null) {
caee6e6c
PS
514 // note: we must not use "question_attempt::get_submitted_var()" because there is no attempt instance!!!
515 if (is_null($postdata)) {
516 $slots = optional_param('slots', null, PARAM_SEQUENCE);
517 } else if (array_key_exists('slots', $postdata)) {
518 $slots = clean_param($postdata['slots'], PARAM_SEQUENCE);
519 } else {
520 $slots = null;
521 }
dcd03928
TH
522 if (is_null($slots)) {
523 $slots = $this->get_slots();
524 } else if (!$slots) {
525 $slots = array();
526 } else {
527 $slots = explode(',', $slots);
528 }
529 foreach ($slots as $slot) {
530 if (!$this->validate_sequence_number($slot, $postdata)) {
531 continue;
532 }
533 $submitteddata = $this->extract_responses($slot, $postdata);
534 $this->process_action($slot, $submitteddata, $timestamp);
535 }
536 $this->update_question_flags($postdata);
537 }
538
539 /**
540 * Get the submitted data from the current request that belongs to this
541 * particular question.
542 *
543 * @param int $slot the number used to identify this question within this usage.
544 * @param $postdata optional, only intended for testing. Use this data
545 * instead of the data from $_POST.
546 * @return array submitted data specific to this question.
547 */
548 public function extract_responses($slot, $postdata = null) {
549 return $this->get_question_attempt($slot)->get_submitted_data($postdata);
550 }
551
552 /**
553 * Process a specific action on a specific question.
554 * @param int $slot the number used to identify this question within this usage.
555 * @param $submitteddata the submitted data that constitutes the action.
556 */
557 public function process_action($slot, $submitteddata, $timestamp = null) {
558 $qa = $this->get_question_attempt($slot);
559 $qa->process_action($submitteddata, $timestamp);
560 $this->observer->notify_attempt_modified($qa);
561 }
562
563 /**
564 * Check that the sequence number, that detects weird things like the student
565 * clicking back, is OK. If the sequence check variable is not present, returns
566 * false. If the check variable is present and correct, returns true. If the
567 * variable is present and wrong, throws an exception.
568 * @param int $slot the number used to identify this question within this usage.
569 * @param array $submitteddata the submitted data that constitutes the action.
570 * @return bool true if the check variable is present and correct. False if it
571 * is missing. (Throws an exception if the check fails.)
572 */
573 public function validate_sequence_number($slot, $postdata = null) {
574 $qa = $this->get_question_attempt($slot);
575 $sequencecheck = $qa->get_submitted_var(
576 $qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
577 if (is_null($sequencecheck)) {
578 return false;
579 } else if ($sequencecheck != $qa->get_num_steps()) {
580 throw new question_out_of_sequence_exception($this->id, $slot, $postdata);
581 } else {
582 return true;
583 }
584 }
585 /**
586 * Update the flagged state for all question_attempts in this usage, if their
587 * flagged state was changed in the request.
588 *
589 * @param $postdata optional, only intended for testing. Use this data
590 * instead of the data from $_POST.
591 */
592 public function update_question_flags($postdata = null) {
593 foreach ($this->questionattempts as $qa) {
594 $flagged = $qa->get_submitted_var(
595 $qa->get_flag_field_name(), PARAM_BOOL, $postdata);
596 if (!is_null($flagged) && $flagged != $qa->is_flagged()) {
597 $qa->set_flagged($flagged);
598 }
599 }
600 }
601
602 /**
603 * Get the correct response to a particular question. Passing the results of
604 * this method to {@link process_action()} will probably result in full marks.
da22c012 605 * If it is not possible to compute a correct response, this method should return null.
dcd03928
TH
606 * @param int $slot the number used to identify this question within this usage.
607 * @return array that constitutes a correct response to this question.
608 */
609 public function get_correct_response($slot) {
610 return $this->get_question_attempt($slot)->get_correct_response();
611 }
612
613 /**
614 * Finish the active phase of an attempt at a question.
615 *
616 * This is an external act of finishing the attempt. Think, for example, of
617 * the 'Submit all and finish' button in the quiz. Some behaviours,
618 * (for example, immediatefeedback) give a way of finishing the active phase
619 * of a question attempt as part of a {@link process_action()} call.
620 *
621 * After the active phase is over, the only changes possible are things like
622 * manual grading, or changing the flag state.
623 *
624 * @param int $slot the number used to identify this question within this usage.
625 */
626 public function finish_question($slot, $timestamp = null) {
627 $qa = $this->get_question_attempt($slot);
628 $qa->finish($timestamp);
629 $this->observer->notify_attempt_modified($qa);
630 }
631
632 /**
633 * Finish the active phase of an attempt at a question. See {@link finish_question()}
634 * for a fuller description of what 'finish' means.
635 */
636 public function finish_all_questions($timestamp = null) {
637 foreach ($this->questionattempts as $qa) {
638 $qa->finish($timestamp);
639 $this->observer->notify_attempt_modified($qa);
640 }
641 }
642
643 /**
644 * Perform a manual grading action on a question attempt.
645 * @param int $slot the number used to identify this question within this usage.
646 * @param string $comment the comment being added to the question attempt.
647 * @param number $mark the mark that is being assigned. Can be null to just
648 * add a comment.
770e4a46 649 * @param int $commentformat one of the FORMAT_... constants. The format of $comment.
dcd03928 650 */
53b8e256 651 public function manual_grade($slot, $comment, $mark, $commentformat = null) {
dcd03928 652 $qa = $this->get_question_attempt($slot);
53b8e256 653 $qa->manual_grade($comment, $mark, $commentformat);
dcd03928
TH
654 $this->observer->notify_attempt_modified($qa);
655 }
656
657 /**
658 * Regrade a question in this usage. This replays the sequence of submitted
659 * actions to recompute the outcomes.
660 * @param int $slot the number used to identify this question within this usage.
661 * @param bool $finished whether the question attempt should be forced to be finished
662 * after the regrade, or whether it may still be in progress (default false).
663 * @param number $newmaxmark (optional) if given, will change the max mark while regrading.
664 */
665 public function regrade_question($slot, $finished = false, $newmaxmark = null) {
666 $oldqa = $this->get_question_attempt($slot);
667 if (is_null($newmaxmark)) {
668 $newmaxmark = $oldqa->get_max_mark();
669 }
670
dcd03928
TH
671 $newqa = new question_attempt($oldqa->get_question(), $oldqa->get_usage_id(),
672 $this->observer, $newmaxmark);
673 $newqa->set_database_id($oldqa->get_database_id());
94815ccf 674 $newqa->set_slot($oldqa->get_slot());
dcd03928
TH
675 $newqa->regrade($oldqa, $finished);
676
677 $this->questionattempts[$slot] = $newqa;
678 $this->observer->notify_attempt_modified($newqa);
679 }
680
681 /**
682 * Regrade all the questions in this usage (without changing their max mark).
683 * @param bool $finished whether each question should be forced to be finished
684 * after the regrade, or whether it may still be in progress (default false).
685 */
686 public function regrade_all_questions($finished = false) {
687 foreach ($this->questionattempts as $slot => $notused) {
688 $this->regrade_question($slot, $finished);
689 }
690 }
691
692 /**
693 * Create a question_usage_by_activity from records loaded from the database.
694 *
695 * For internal use only.
696 *
35d5f1c2 697 * @param Iterator $records Raw records loaded from the database.
dcd03928 698 * @param int $questionattemptid The id of the question_attempt to extract.
94815ccf 699 * @return question_usage_by_activity The newly constructed usage.
dcd03928 700 */
35d5f1c2
TH
701 public static function load_from_records($records, $qubaid) {
702 $record = $records->current();
dcd03928 703 while ($record->qubaid != $qubaid) {
35d5f1c2
TH
704 $records->next();
705 if (!$records->valid()) {
dcd03928
TH
706 throw new coding_exception("Question usage $qubaid not found in the database.");
707 }
35d5f1c2 708 $record = $records->current();
dcd03928
TH
709 }
710
711 $quba = new question_usage_by_activity($record->component,
2cdd5d85 712 context::instance_by_id($record->contextid, IGNORE_MISSING));
dcd03928
TH
713 $quba->set_id_from_database($record->qubaid);
714 $quba->set_preferred_behaviour($record->preferredbehaviour);
715
716 $quba->observer = new question_engine_unit_of_work($quba);
717
dd7aa583
TH
718 // If slot is null then the current pointer in $records will not be
719 // advanced in the while loop below, and we get stuck in an infinite loop,
720 // since this method is supposed to always consume at least one record.
721 // Therefore, in this case, advance the record here.
722 if (is_null($record->slot)) {
723 $records->next();
724 }
725
dcd03928
TH
726 while ($record && $record->qubaid == $qubaid && !is_null($record->slot)) {
727 $quba->questionattempts[$record->slot] =
728 question_attempt::load_from_records($records,
729 $record->questionattemptid, $quba->observer,
730 $quba->get_preferred_behaviour());
35d5f1c2
TH
731 if ($records->valid()) {
732 $record = $records->current();
733 } else {
734 $record = false;
735 }
dcd03928
TH
736 }
737
738 return $quba;
739 }
740}
741
742
743/**
744 * A class abstracting access to the
745 * {@link question_usage_by_activity::$questionattempts} array.
746 *
747 * This class snapshots the list of {@link question_attempts} to iterate over
748 * when it is created. If a question is added to the usage mid-iteration, it
749 * will now show up.
750 *
751 * To create an instance of this class, use
752 * {@link question_usage_by_activity::get_attempt_iterator()}
753 *
754 * @copyright 2009 The Open University
755 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
756 */
757class question_attempt_iterator implements Iterator, ArrayAccess {
758 /** @var question_usage_by_activity that we are iterating over. */
759 protected $quba;
760 /** @var array of question numbers. */
761 protected $slots;
762
763 /**
9c197f44
TH
764 * To create an instance of this class, use
765 * {@link question_usage_by_activity::get_attempt_iterator()}.
dcd03928
TH
766 * @param $quba the usage to iterate over.
767 */
768 public function __construct(question_usage_by_activity $quba) {
769 $this->quba = $quba;
770 $this->slots = $quba->get_slots();
771 $this->rewind();
772 }
773
774 /** @return question_attempt_step */
775 public function current() {
776 return $this->offsetGet(current($this->slots));
777 }
778 /** @return int */
779 public function key() {
780 return current($this->slots);
781 }
782 public function next() {
783 next($this->slots);
784 }
785 public function rewind() {
786 reset($this->slots);
787 }
788 /** @return bool */
789 public function valid() {
790 return current($this->slots) !== false;
791 }
792
793 /** @return bool */
794 public function offsetExists($slot) {
795 return in_array($slot, $this->slots);
796 }
797 /** @return question_attempt_step */
798 public function offsetGet($slot) {
799 return $this->quba->get_question_attempt($slot);
800 }
801 public function offsetSet($slot, $value) {
9c197f44
TH
802 throw new coding_exception('You are only allowed read-only access to ' .
803 'question_attempt::states through a question_attempt_step_iterator. Cannot set.');
dcd03928
TH
804 }
805 public function offsetUnset($slot) {
9c197f44
TH
806 throw new coding_exception('You are only allowed read-only access to ' .
807 'question_attempt::states through a question_attempt_step_iterator. Cannot unset.');
dcd03928
TH
808 }
809}
810
811
812/**
813 * Interface for things that want to be notified of signficant changes to a
814 * {@link question_usage_by_activity}.
815 *
816 * A question behaviour controls the flow of actions a student can
817 * take as they work through a question, and later, as a teacher manually grades it.
818 *
819 * @copyright 2009 The Open University
820 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
821 */
822interface question_usage_observer {
823 /** Called when a field of the question_usage_by_activity is changed. */
824 public function notify_modified();
825
826 /**
827 * Called when the fields of a question attempt in this usage are modified.
828 * @param question_attempt $qa the newly added question attempt.
829 */
830 public function notify_attempt_modified(question_attempt $qa);
831
832 /**
833 * Called when a new question attempt is added to this usage.
834 * @param question_attempt $qa the newly added question attempt.
835 */
836 public function notify_attempt_added(question_attempt $qa);
837
838 /**
94815ccf
TH
839 * Called when a new step is added to a question attempt in this usage.
840 * @param question_attempt_step $step the new step.
841 * @param question_attempt $qa the usage it is being added to.
842 * @param int $seq the sequence number of the new step.
dcd03928 843 */
94815ccf 844 public function notify_step_added(question_attempt_step $step, question_attempt $qa, $seq);
dcd03928
TH
845
846 /**
94815ccf
TH
847 * Called when a new step is updated in a question attempt in this usage.
848 * @param question_attempt_step $step the step that was updated.
849 * @param question_attempt $qa the usage it is being added to.
850 * @param int $seq the sequence number of the new step.
dcd03928 851 */
94815ccf
TH
852 public function notify_step_modified(question_attempt_step $step, question_attempt $qa, $seq);
853
854 /**
855 * Called when a new step is updated in a question attempt in this usage.
856 * @param question_attempt_step $step the step to delete.
857 * @param question_attempt $qa the usage it is being added to.
858 */
859 public function notify_step_deleted(question_attempt_step $step, question_attempt $qa);
860
dcd03928
TH
861}
862
863
864/**
865 * Null implmentation of the {@link question_usage_watcher} interface.
866 * Does nothing.
867 *
868 * @copyright 2009 The Open University
869 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
870 */
871class question_usage_null_observer implements question_usage_observer {
872 public function notify_modified() {
873 }
874 public function notify_attempt_modified(question_attempt $qa) {
875 }
876 public function notify_attempt_added(question_attempt $qa) {
877 }
dcd03928
TH
878 public function notify_step_added(question_attempt_step $step, question_attempt $qa, $seq) {
879 }
94815ccf
TH
880 public function notify_step_modified(question_attempt_step $step, question_attempt $qa, $seq) {
881 }
882 public function notify_step_deleted(question_attempt_step $step, question_attempt $qa) {
883 }
dcd03928 884}