MDL-32188 question engine: behaviour static methods -> new classes
[moodle.git] / question / engine / questionusage.php
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dcd03928 1<?php
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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. */
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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. */
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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
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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
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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
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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);
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169 $qa->set_slot($this->next_slot_number());
170 $this->questionattempts[$this->next_slot_number()] = $qa;
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171 $this->observer->notify_attempt_added($qa);
172 return $qa->get_slot();
173 }
174
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175 /**
176 * The slot number that will be allotted to the next question added.
177 */
178 public function next_slot_number() {
179 return count($this->questionattempts) + 1;
180 }
181
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182 /**
183 * Get the question_definition for a question in this attempt.
184 * @param int $slot the number used to identify this question within this usage.
185 * @return question_definition the requested question object.
186 */
187 public function get_question($slot) {
188 return $this->get_question_attempt($slot)->get_question();
189 }
190
191 /** @return array all the identifying numbers of all the questions in this usage. */
192 public function get_slots() {
193 return array_keys($this->questionattempts);
194 }
195
196 /** @return int the identifying number of the first question that was added to this usage. */
197 public function get_first_question_number() {
198 reset($this->questionattempts);
199 return key($this->questionattempts);
200 }
201
202 /** @return int the number of questions that are currently in this usage. */
203 public function question_count() {
204 return count($this->questionattempts);
205 }
206
207 /**
208 * Note the part of the {@link question_usage_by_activity} comment that explains
209 * that {@link question_attempt} objects should be considered part of the inner
210 * workings of the question engine, and should not, if possible, be accessed directly.
211 *
212 * @return question_attempt_iterator for iterating over all the questions being
213 * attempted. as part of this usage.
214 */
215 public function get_attempt_iterator() {
216 return new question_attempt_iterator($this);
217 }
218
219 /**
220 * Check whether $number actually corresponds to a question attempt that is
221 * part of this usage. Throws an exception if not.
222 *
223 * @param int $slot a number allegedly identifying a question within this usage.
224 */
225 protected function check_slot($slot) {
226 if (!array_key_exists($slot, $this->questionattempts)) {
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227 throw new coding_exception('There is no question_attempt number ' . $slot .
228 ' in this attempt.');
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229 }
230 }
231
232 /**
233 * Note the part of the {@link question_usage_by_activity} comment that explains
234 * that {@link question_attempt} objects should be considered part of the inner
235 * workings of the question engine, and should not, if possible, be accessed directly.
236 *
237 * @param int $slot the number used to identify this question within this usage.
238 * @return question_attempt the corresponding {@link question_attempt} object.
239 */
240 public function get_question_attempt($slot) {
241 $this->check_slot($slot);
242 return $this->questionattempts[$slot];
243 }
244
245 /**
246 * Get the current state of the attempt at a question.
247 * @param int $slot the number used to identify this question within this usage.
248 * @return question_state.
249 */
250 public function get_question_state($slot) {
251 return $this->get_question_attempt($slot)->get_state();
252 }
253
254 /**
255 * @param int $slot the number used to identify this question within this usage.
256 * @param bool $showcorrectness Whether right/partial/wrong states should
257 * be distinguised.
258 * @return string A brief textual description of the current state.
259 */
260 public function get_question_state_string($slot, $showcorrectness) {
261 return $this->get_question_attempt($slot)->get_state_string($showcorrectness);
262 }
263
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264 /**
265 * @param int $slot the number used to identify this question within this usage.
266 * @param bool $showcorrectness Whether right/partial/wrong states should
267 * be distinguised.
268 * @return string a CSS class name for the current state.
269 */
270 public function get_question_state_class($slot, $showcorrectness) {
271 return $this->get_question_attempt($slot)->get_state_class($showcorrectness);
272 }
273
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274 /**
275 * Get the time of the most recent action performed on a question.
276 * @param int $slot the number used to identify this question within this usage.
277 * @return int timestamp.
278 */
279 public function get_question_action_time($slot) {
280 return $this->get_question_attempt($slot)->get_last_action_time();
281 }
282
283 /**
284 * Get the current fraction awarded for the attempt at a question.
285 * @param int $slot the number used to identify this question within this usage.
286 * @return number|null The current fraction for this question, or null if one has
287 * not been assigned yet.
288 */
289 public function get_question_fraction($slot) {
290 return $this->get_question_attempt($slot)->get_fraction();
291 }
292
293 /**
294 * Get the current mark awarded for the attempt at a question.
295 * @param int $slot the number used to identify this question within this usage.
296 * @return number|null The current mark for this question, or null if one has
297 * not been assigned yet.
298 */
299 public function get_question_mark($slot) {
300 return $this->get_question_attempt($slot)->get_mark();
301 }
302
303 /**
304 * Get the maximum mark possible for the attempt at a question.
305 * @param int $slot the number used to identify this question within this usage.
306 * @return number the available marks for this question.
307 */
308 public function get_question_max_mark($slot) {
309 return $this->get_question_attempt($slot)->get_max_mark();
310 }
311
312 /**
313 * Get the current mark awarded for the attempt at a question.
314 * @param int $slot the number used to identify this question within this usage.
315 * @return number|null The current mark for this question, or null if one has
316 * not been assigned yet.
317 */
318 public function get_total_mark() {
319 $mark = 0;
320 foreach ($this->questionattempts as $qa) {
321 if ($qa->get_max_mark() > 0 && $qa->get_state() == question_state::$needsgrading) {
322 return null;
323 }
324 $mark += $qa->get_mark();
325 }
326 return $mark;
327 }
328
329 /**
330 * @return string a simple textual summary of the question that was asked.
331 */
332 public function get_question_summary($slot) {
333 return $this->get_question_attempt($slot)->get_question_summary();
334 }
335
336 /**
337 * @return string a simple textual summary of response given.
338 */
339 public function get_response_summary($slot) {
340 return $this->get_question_attempt($slot)->get_response_summary();
341 }
342
343 /**
344 * @return string a simple textual summary of the correct resonse.
345 */
346 public function get_right_answer_summary($slot) {
347 return $this->get_question_attempt($slot)->get_right_answer_summary();
348 }
349
350 /**
351 * Get the {@link core_question_renderer}, in collaboration with appropriate
352 * {@link qbehaviour_renderer} and {@link qtype_renderer} subclasses, to generate the
353 * HTML to display this question.
354 * @param int $slot the number used to identify this question within this usage.
355 * @param question_display_options $options controls how the question is rendered.
356 * @param string|null $number The question number to display. 'i' is a special
357 * value that gets displayed as Information. Null means no number is displayed.
358 * @return string HTML fragment representing the question.
359 */
360 public function render_question($slot, $options, $number = null) {
361 $options->context = $this->context;
362 return $this->get_question_attempt($slot)->render($options, $number);
363 }
364
365 /**
366 * Generate any bits of HTML that needs to go in the <head> tag when this question
367 * is displayed in the body.
368 * @param int $slot the number used to identify this question within this usage.
369 * @return string HTML fragment.
370 */
371 public function render_question_head_html($slot) {
92701024 372 //$options->context = $this->context;
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373 return $this->get_question_attempt($slot)->render_head_html();
374 }
375
376 /**
377 * Like {@link render_question()} but displays the question at the past step
378 * indicated by $seq, rather than showing the latest step.
379 *
380 * @param int $slot the number used to identify this question within this usage.
381 * @param int $seq the seq number of the past state to display.
382 * @param question_display_options $options controls how the question is rendered.
383 * @param string|null $number The question number to display. 'i' is a special
384 * value that gets displayed as Information. Null means no number is displayed.
385 * @return string HTML fragment representing the question.
386 */
387 public function render_question_at_step($slot, $seq, $options, $number = null) {
388 $options->context = $this->context;
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389 return $this->get_question_attempt($slot)->render_at_step(
390 $seq, $options, $number, $this->preferredbehaviour);
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391 }
392
393 /**
394 * Checks whether the users is allow to be served a particular file.
395 * @param int $slot the number used to identify this question within this usage.
396 * @param question_display_options $options the options that control display of the question.
397 * @param string $component the name of the component we are serving files for.
398 * @param string $filearea the name of the file area.
399 * @param array $args the remaining bits of the file path.
400 * @param bool $forcedownload whether the user must be forced to download the file.
401 * @return bool true if the user can access this file.
402 */
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403 public function check_file_access($slot, $options, $component, $filearea,
404 $args, $forcedownload) {
405 return $this->get_question_attempt($slot)->check_file_access(
406 $options, $component, $filearea, $args, $forcedownload);
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407 }
408
409 /**
410 * Replace a particular question_attempt with a different one.
411 *
412 * For internal use only. Used when reloading the state of a question from the
413 * database.
414 *
415 * @param array $records Raw records loaded from the database.
416 * @param int $questionattemptid The id of the question_attempt to extract.
417 * @return question_attempt The newly constructed question_attempt_step.
418 */
419 public function replace_loaded_question_attempt_info($slot, $qa) {
420 $this->check_slot($slot);
421 $this->questionattempts[$slot] = $qa;
422 }
423
424 /**
425 * You should probably not use this method in code outside the question engine.
426 * The main reason for exposing it was for the benefit of unit tests.
427 * @param int $slot the number used to identify this question within this usage.
428 * @return string return the prefix that is pre-pended to field names in the HTML
429 * that is output.
430 */
431 public function get_field_prefix($slot) {
432 return $this->get_question_attempt($slot)->get_field_prefix();
433 }
434
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435 /**
436 * Get the number of variants available for the question in this slot.
437 * @param int $slot the number used to identify this question within this usage.
438 * @return int the number of variants available.
439 */
440 public function get_num_variants($slot) {
441 return $this->get_question_attempt($slot)->get_question()->get_num_variants();
442 }
443
444 /**
445 * Get the variant of the question being used in a given slot.
446 * @param int $slot the number used to identify this question within this usage.
447 * @return int the variant of this question that is being used.
448 */
449 public function get_variant($slot) {
450 return $this->get_question_attempt($slot)->get_variant();
451 }
452
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453 /**
454 * Start the attempt at a question that has been added to this usage.
455 * @param int $slot the number used to identify this question within this usage.
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456 * @param int $variant which variant of the question to use. Must be between
457 * 1 and ->get_num_variants($slot) inclusive. If not give, a variant is
458 * chosen at random.
dcd03928 459 */
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460 public function start_question($slot, $variant = null) {
461 if (is_null($variant)) {
462 $variant = rand(1, $this->get_num_variants($slot));
463 }
464
dcd03928 465 $qa = $this->get_question_attempt($slot);
1da821bb 466 $qa->start($this->preferredbehaviour, $variant);
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467 $this->observer->notify_attempt_modified($qa);
468 }
469
470 /**
471 * Start the attempt at all questions that has been added to this usage.
1da821bb 472 * @param question_variant_selection_strategy how to pick which variant of each question to use.
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473 * @param int $timestamp optional, the timstamp to record for this action. Defaults to now.
474 * @param int $userid optional, the user to attribute this action to. Defaults to the current user.
dcd03928 475 */
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476 public function start_all_questions(question_variant_selection_strategy $variantstrategy = null,
477 $timestamp = null, $userid = null) {
478 if (is_null($variantstrategy)) {
479 $variantstrategy = new question_variant_random_strategy();
480 }
481
dcd03928 482 foreach ($this->questionattempts as $qa) {
1da821bb 483 $qa->start($this->preferredbehaviour, $qa->select_variant($variantstrategy));
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484 $this->observer->notify_attempt_modified($qa);
485 }
486 }
487
488 /**
489 * Start the attempt at a question, starting from the point where the previous
490 * question_attempt $oldqa had reached. This is used by the quiz 'Each attempt
491 * builds on last' mode.
492 * @param int $slot the number used to identify this question within this usage.
493 * @param question_attempt $oldqa a previous attempt at this quetsion that
494 * defines the starting point.
495 */
496 public function start_question_based_on($slot, question_attempt $oldqa) {
497 $qa = $this->get_question_attempt($slot);
498 $qa->start_based_on($oldqa);
499 $this->observer->notify_attempt_modified($qa);
500 }
501
502 /**
503 * Process all the question actions in the current request.
504 *
505 * If there is a parameter slots included in the post data, then only
506 * those question numbers will be processed, otherwise all questions in this
507 * useage will be.
508 *
509 * This function also does {@link update_question_flags()}.
510 *
511 * @param int $timestamp optional, use this timestamp as 'now'.
512 * @param array $postdata optional, only intended for testing. Use this data
513 * instead of the data from $_POST.
514 */
515 public function process_all_actions($timestamp = null, $postdata = null) {
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516 foreach ($this->get_slots_in_request($postdata) as $slot) {
517 if (!$this->validate_sequence_number($slot, $postdata)) {
518 continue;
519 }
520 $submitteddata = $this->extract_responses($slot, $postdata);
521 $this->process_action($slot, $submitteddata, $timestamp);
522 }
523 $this->update_question_flags($postdata);
524 }
525
526 /**
527 * Process all the question autosave data in the current request.
528 *
529 * If there is a parameter slots included in the post data, then only
530 * those question numbers will be processed, otherwise all questions in this
531 * useage will be.
532 *
533 * This function also does {@link update_question_flags()}.
534 *
535 * @param int $timestamp optional, use this timestamp as 'now'.
536 * @param array $postdata optional, only intended for testing. Use this data
537 * instead of the data from $_POST.
538 */
539 public function process_all_autosaves($timestamp = null, $postdata = null) {
540 foreach ($this->get_slots_in_request($postdata) as $slot) {
541 if (!$this->is_autosave_required($slot, $postdata)) {
542 continue;
543 }
544 $submitteddata = $this->extract_responses($slot, $postdata);
545 $this->process_autosave($slot, $submitteddata, $timestamp);
546 }
547 $this->update_question_flags($postdata);
548 }
549
550 /**
551 * Get the list of slot numbers that should be processed as part of processing
552 * the current request.
553 * @param array $postdata optional, only intended for testing. Use this data
554 * instead of the data from $_POST.
555 * @return array of slot numbers.
556 */
557 protected function get_slots_in_request($postdata = null) {
558 // Note: we must not use "question_attempt::get_submitted_var()" because there is no attempt instance!!!
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559 if (is_null($postdata)) {
560 $slots = optional_param('slots', null, PARAM_SEQUENCE);
561 } else if (array_key_exists('slots', $postdata)) {
562 $slots = clean_param($postdata['slots'], PARAM_SEQUENCE);
563 } else {
564 $slots = null;
565 }
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566 if (is_null($slots)) {
567 $slots = $this->get_slots();
568 } else if (!$slots) {
569 $slots = array();
570 } else {
571 $slots = explode(',', $slots);
572 }
0a606a2b 573 return $slots;
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574 }
575
576 /**
577 * Get the submitted data from the current request that belongs to this
578 * particular question.
579 *
580 * @param int $slot the number used to identify this question within this usage.
581 * @param $postdata optional, only intended for testing. Use this data
582 * instead of the data from $_POST.
583 * @return array submitted data specific to this question.
584 */
585 public function extract_responses($slot, $postdata = null) {
586 return $this->get_question_attempt($slot)->get_submitted_data($postdata);
587 }
588
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589 /**
590 * Transform an array of response data for slots to an array of post data as you would get from quiz attempt form.
591 *
592 * @param $simulatedresponses array keys are slot nos => contains arrays representing student
593 * responses which will be passed to question_definition::prepare_simulated_post_data method
594 * and then have the appropriate prefix added.
595 * @return array simulated post data
596 */
597 public function prepare_simulated_post_data($simulatedresponses) {
598 $simulatedpostdata = array();
599 $simulatedpostdata['slots'] = implode(',', array_keys($simulatedresponses));
600 foreach ($simulatedresponses as $slot => $responsedata) {
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601 $slotresponse = array();
602
603 // Behaviour vars should not be processed by question type, just add prefix.
604 $behaviourvars = $this->get_question_attempt($slot)->get_behaviour()->get_expected_data();
605 foreach ($behaviourvars as $behaviourvarname => $unused) {
606 $behaviourvarkey = '-'.$behaviourvarname;
607 if (isset($responsedata[$behaviourvarkey])) {
608 $slotresponse[$behaviourvarkey] = $responsedata[$behaviourvarkey];
609 unset($responsedata[$behaviourvarkey]);
610 }
611 }
612
613 $slotresponse += $this->get_question($slot)->prepare_simulated_post_data($responsedata);
388f0473 614 $slotresponse[':sequencecheck'] = $this->get_question_attempt($slot)->get_sequence_check_count();
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615
616 // Add this slot's prefix to slot data.
617 $prefix = $this->get_field_prefix($slot);
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618 foreach ($slotresponse as $key => $value) {
619 $simulatedpostdata[$prefix.$key] = $value;
620 }
621 }
622 return $simulatedpostdata;
623 }
624
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625 /**
626 * Process a specific action on a specific question.
627 * @param int $slot the number used to identify this question within this usage.
628 * @param $submitteddata the submitted data that constitutes the action.
629 */
630 public function process_action($slot, $submitteddata, $timestamp = null) {
631 $qa = $this->get_question_attempt($slot);
632 $qa->process_action($submitteddata, $timestamp);
633 $this->observer->notify_attempt_modified($qa);
634 }
635
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636 /**
637 * Process an autosave action on a specific question.
638 * @param int $slot the number used to identify this question within this usage.
639 * @param $submitteddata the submitted data that constitutes the action.
640 */
641 public function process_autosave($slot, $submitteddata, $timestamp = null) {
642 $qa = $this->get_question_attempt($slot);
643 if ($qa->process_autosave($submitteddata, $timestamp)) {
644 $this->observer->notify_attempt_modified($qa);
645 }
646 }
647
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648 /**
649 * Check that the sequence number, that detects weird things like the student
650 * clicking back, is OK. If the sequence check variable is not present, returns
651 * false. If the check variable is present and correct, returns true. If the
652 * variable is present and wrong, throws an exception.
653 * @param int $slot the number used to identify this question within this usage.
654 * @param array $submitteddata the submitted data that constitutes the action.
655 * @return bool true if the check variable is present and correct. False if it
656 * is missing. (Throws an exception if the check fails.)
657 */
658 public function validate_sequence_number($slot, $postdata = null) {
659 $qa = $this->get_question_attempt($slot);
660 $sequencecheck = $qa->get_submitted_var(
661 $qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
662 if (is_null($sequencecheck)) {
663 return false;
c7fbfe46 664 } else if ($sequencecheck != $qa->get_sequence_check_count()) {
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665 throw new question_out_of_sequence_exception($this->id, $slot, $postdata);
666 } else {
667 return true;
668 }
669 }
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670
671 /**
672 * Check, based on the sequence number, whether this auto-save is still required.
673 * @param int $slot the number used to identify this question within this usage.
674 * @param array $submitteddata the submitted data that constitutes the action.
675 * @return bool true if the check variable is present and correct, otherwise false.
676 */
677 public function is_autosave_required($slot, $postdata = null) {
678 $qa = $this->get_question_attempt($slot);
679 $sequencecheck = $qa->get_submitted_var(
680 $qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
681 if (is_null($sequencecheck)) {
682 return false;
c7fbfe46 683 } else if ($sequencecheck != $qa->get_sequence_check_count()) {
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684 return false;
685 } else {
686 return true;
687 }
688 }
689
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690 /**
691 * Update the flagged state for all question_attempts in this usage, if their
692 * flagged state was changed in the request.
693 *
694 * @param $postdata optional, only intended for testing. Use this data
695 * instead of the data from $_POST.
696 */
697 public function update_question_flags($postdata = null) {
698 foreach ($this->questionattempts as $qa) {
699 $flagged = $qa->get_submitted_var(
700 $qa->get_flag_field_name(), PARAM_BOOL, $postdata);
701 if (!is_null($flagged) && $flagged != $qa->is_flagged()) {
702 $qa->set_flagged($flagged);
703 }
704 }
705 }
706
707 /**
708 * Get the correct response to a particular question. Passing the results of
709 * this method to {@link process_action()} will probably result in full marks.
da22c012 710 * If it is not possible to compute a correct response, this method should return null.
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711 * @param int $slot the number used to identify this question within this usage.
712 * @return array that constitutes a correct response to this question.
713 */
714 public function get_correct_response($slot) {
715 return $this->get_question_attempt($slot)->get_correct_response();
716 }
717
718 /**
719 * Finish the active phase of an attempt at a question.
720 *
721 * This is an external act of finishing the attempt. Think, for example, of
722 * the 'Submit all and finish' button in the quiz. Some behaviours,
723 * (for example, immediatefeedback) give a way of finishing the active phase
724 * of a question attempt as part of a {@link process_action()} call.
725 *
726 * After the active phase is over, the only changes possible are things like
727 * manual grading, or changing the flag state.
728 *
729 * @param int $slot the number used to identify this question within this usage.
730 */
731 public function finish_question($slot, $timestamp = null) {
732 $qa = $this->get_question_attempt($slot);
733 $qa->finish($timestamp);
734 $this->observer->notify_attempt_modified($qa);
735 }
736
737 /**
738 * Finish the active phase of an attempt at a question. See {@link finish_question()}
739 * for a fuller description of what 'finish' means.
740 */
741 public function finish_all_questions($timestamp = null) {
742 foreach ($this->questionattempts as $qa) {
743 $qa->finish($timestamp);
744 $this->observer->notify_attempt_modified($qa);
745 }
746 }
747
748 /**
749 * Perform a manual grading action on a question attempt.
750 * @param int $slot the number used to identify this question within this usage.
751 * @param string $comment the comment being added to the question attempt.
752 * @param number $mark the mark that is being assigned. Can be null to just
753 * add a comment.
770e4a46 754 * @param int $commentformat one of the FORMAT_... constants. The format of $comment.
dcd03928 755 */
53b8e256 756 public function manual_grade($slot, $comment, $mark, $commentformat = null) {
dcd03928 757 $qa = $this->get_question_attempt($slot);
53b8e256 758 $qa->manual_grade($comment, $mark, $commentformat);
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759 $this->observer->notify_attempt_modified($qa);
760 }
761
762 /**
763 * Regrade a question in this usage. This replays the sequence of submitted
764 * actions to recompute the outcomes.
765 * @param int $slot the number used to identify this question within this usage.
766 * @param bool $finished whether the question attempt should be forced to be finished
767 * after the regrade, or whether it may still be in progress (default false).
768 * @param number $newmaxmark (optional) if given, will change the max mark while regrading.
769 */
770 public function regrade_question($slot, $finished = false, $newmaxmark = null) {
771 $oldqa = $this->get_question_attempt($slot);
772 if (is_null($newmaxmark)) {
773 $newmaxmark = $oldqa->get_max_mark();
774 }
775
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776 $newqa = new question_attempt($oldqa->get_question(), $oldqa->get_usage_id(),
777 $this->observer, $newmaxmark);
778 $newqa->set_database_id($oldqa->get_database_id());
94815ccf 779 $newqa->set_slot($oldqa->get_slot());
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780 $newqa->regrade($oldqa, $finished);
781
782 $this->questionattempts[$slot] = $newqa;
783 $this->observer->notify_attempt_modified($newqa);
784 }
785
786 /**
787 * Regrade all the questions in this usage (without changing their max mark).
788 * @param bool $finished whether each question should be forced to be finished
789 * after the regrade, or whether it may still be in progress (default false).
790 */
791 public function regrade_all_questions($finished = false) {
792 foreach ($this->questionattempts as $slot => $notused) {
793 $this->regrade_question($slot, $finished);
794 }
795 }
796
797 /**
798 * Create a question_usage_by_activity from records loaded from the database.
799 *
800 * For internal use only.
801 *
35d5f1c2 802 * @param Iterator $records Raw records loaded from the database.
dcd03928 803 * @param int $questionattemptid The id of the question_attempt to extract.
94815ccf 804 * @return question_usage_by_activity The newly constructed usage.
dcd03928 805 */
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806 public static function load_from_records($records, $qubaid) {
807 $record = $records->current();
dcd03928 808 while ($record->qubaid != $qubaid) {
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809 $records->next();
810 if (!$records->valid()) {
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811 throw new coding_exception("Question usage $qubaid not found in the database.");
812 }
35d5f1c2 813 $record = $records->current();
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814 }
815
816 $quba = new question_usage_by_activity($record->component,
2cdd5d85 817 context::instance_by_id($record->contextid, IGNORE_MISSING));
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818 $quba->set_id_from_database($record->qubaid);
819 $quba->set_preferred_behaviour($record->preferredbehaviour);
820
821 $quba->observer = new question_engine_unit_of_work($quba);
822
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823 // If slot is null then the current pointer in $records will not be
824 // advanced in the while loop below, and we get stuck in an infinite loop,
825 // since this method is supposed to always consume at least one record.
826 // Therefore, in this case, advance the record here.
827 if (is_null($record->slot)) {
828 $records->next();
829 }
830
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831 while ($record && $record->qubaid == $qubaid && !is_null($record->slot)) {
832 $quba->questionattempts[$record->slot] =
833 question_attempt::load_from_records($records,
834 $record->questionattemptid, $quba->observer,
835 $quba->get_preferred_behaviour());
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836 if ($records->valid()) {
837 $record = $records->current();
838 } else {
839 $record = false;
840 }
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841 }
842
843 return $quba;
844 }
845}
846
847
848/**
849 * A class abstracting access to the
850 * {@link question_usage_by_activity::$questionattempts} array.
851 *
852 * This class snapshots the list of {@link question_attempts} to iterate over
853 * when it is created. If a question is added to the usage mid-iteration, it
854 * will now show up.
855 *
856 * To create an instance of this class, use
857 * {@link question_usage_by_activity::get_attempt_iterator()}
858 *
859 * @copyright 2009 The Open University
860 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
861 */
862class question_attempt_iterator implements Iterator, ArrayAccess {
863 /** @var question_usage_by_activity that we are iterating over. */
864 protected $quba;
865 /** @var array of question numbers. */
866 protected $slots;
867
868 /**
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869 * To create an instance of this class, use
870 * {@link question_usage_by_activity::get_attempt_iterator()}.
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871 * @param $quba the usage to iterate over.
872 */
873 public function __construct(question_usage_by_activity $quba) {
874 $this->quba = $quba;
875 $this->slots = $quba->get_slots();
876 $this->rewind();
877 }
878
879 /** @return question_attempt_step */
880 public function current() {
881 return $this->offsetGet(current($this->slots));
882 }
883 /** @return int */
884 public function key() {
885 return current($this->slots);
886 }
887 public function next() {
888 next($this->slots);
889 }
890 public function rewind() {
891 reset($this->slots);
892 }
893 /** @return bool */
894 public function valid() {
895 return current($this->slots) !== false;
896 }
897
898 /** @return bool */
899 public function offsetExists($slot) {
900 return in_array($slot, $this->slots);
901 }
902 /** @return question_attempt_step */
903 public function offsetGet($slot) {
904 return $this->quba->get_question_attempt($slot);
905 }
906 public function offsetSet($slot, $value) {
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907 throw new coding_exception('You are only allowed read-only access to ' .
908 'question_attempt::states through a question_attempt_step_iterator. Cannot set.');
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909 }
910 public function offsetUnset($slot) {
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911 throw new coding_exception('You are only allowed read-only access to ' .
912 'question_attempt::states through a question_attempt_step_iterator. Cannot unset.');
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913 }
914}
915
916
917/**
918 * Interface for things that want to be notified of signficant changes to a
919 * {@link question_usage_by_activity}.
920 *
921 * A question behaviour controls the flow of actions a student can
922 * take as they work through a question, and later, as a teacher manually grades it.
923 *
924 * @copyright 2009 The Open University
925 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
926 */
927interface question_usage_observer {
928 /** Called when a field of the question_usage_by_activity is changed. */
929 public function notify_modified();
930
931 /**
932 * Called when the fields of a question attempt in this usage are modified.
933 * @param question_attempt $qa the newly added question attempt.
934 */
935 public function notify_attempt_modified(question_attempt $qa);
936
937 /**
938 * Called when a new question attempt is added to this usage.
939 * @param question_attempt $qa the newly added question attempt.
940 */
941 public function notify_attempt_added(question_attempt $qa);
942
943 /**
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944 * Called when a new step is added to a question attempt in this usage.
945 * @param question_attempt_step $step the new step.
946 * @param question_attempt $qa the usage it is being added to.
947 * @param int $seq the sequence number of the new step.
dcd03928 948 */
94815ccf 949 public function notify_step_added(question_attempt_step $step, question_attempt $qa, $seq);
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950
951 /**
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952 * Called when a new step is updated in a question attempt in this usage.
953 * @param question_attempt_step $step the step that was updated.
954 * @param question_attempt $qa the usage it is being added to.
955 * @param int $seq the sequence number of the new step.
dcd03928 956 */
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957 public function notify_step_modified(question_attempt_step $step, question_attempt $qa, $seq);
958
959 /**
960 * Called when a new step is updated in a question attempt in this usage.
961 * @param question_attempt_step $step the step to delete.
962 * @param question_attempt $qa the usage it is being added to.
963 */
964 public function notify_step_deleted(question_attempt_step $step, question_attempt $qa);
965
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966}
967
968
969/**
970 * Null implmentation of the {@link question_usage_watcher} interface.
971 * Does nothing.
972 *
973 * @copyright 2009 The Open University
974 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
975 */
976class question_usage_null_observer implements question_usage_observer {
977 public function notify_modified() {
978 }
979 public function notify_attempt_modified(question_attempt $qa) {
980 }
981 public function notify_attempt_added(question_attempt $qa) {
982 }
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983 public function notify_step_added(question_attempt_step $step, question_attempt $qa, $seq) {
984 }
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985 public function notify_step_modified(question_attempt_step $step, question_attempt $qa, $seq) {
986 }
987 public function notify_step_deleted(question_attempt_step $step, question_attempt $qa) {
988 }
dcd03928 989}