MDL-44075 quiz_statistics : Various coding style / phpdocs fixes
[moodle.git] / question / type / questionbase.php
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d1b7e03d 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
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17/**
18 * This file defines the class {@link question_definition} and its subclasses.
19 *
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20 * The type hierarchy is quite complex. Here is a summary:
21 * - question_definition
22 * - question_information_item
23 * - question_with_responses implements question_manually_gradable
24 * - question_graded_automatically implements question_automatically_gradable
25 * - question_graded_automatically_with_countback implements question_automatically_gradable_with_countback
26 * - question_graded_by_strategy
27 *
28 * Other classes:
29 * - question_classified_response
30 * - question_answer
31 * - question_hint
32 * - question_hint_with_parts
33 * - question_first_matching_answer_grading_strategy implements question_grading_strategy
34 *
35 * Other interfaces:
36 * - question_response_answer_comparer
37 *
b04a4319 38 * @package moodlecore
d1b7e03d 39 * @subpackage questiontypes
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40 * @copyright 2009 The Open University
41 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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42 */
43
44
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45defined('MOODLE_INTERNAL') || die();
46
47
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48/**
49 * The definition of a question of a particular type.
50 *
51 * This class is a close match to the question table in the database.
52 * Definitions of question of a particular type normally subclass one of the
53 * more specific classes {@link question_with_responses},
54 * {@link question_graded_automatically} or {@link question_information_item}.
55 *
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56 * @copyright 2009 The Open University
57 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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58 */
59abstract class question_definition {
60 /** @var integer id of the question in the datase, or null if this question
61 * is not in the database. */
62 public $id;
63
64 /** @var integer question category id. */
65 public $category;
66
e35ba43c 67 /** @var integer question context id. */
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68 public $contextid;
69
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70 /** @var integer parent question id. */
71 public $parent = 0;
72
73 /** @var question_type the question type this question is. */
74 public $qtype;
75
76 /** @var string question name. */
77 public $name;
78
79 /** @var string question text. */
80 public $questiontext;
81
82 /** @var integer question test format. */
83 public $questiontextformat;
84
85 /** @var string question general feedback. */
86 public $generalfeedback;
87
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88 /** @var integer question test format. */
89 public $generalfeedbackformat;
90
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91 /** @var number what this quetsion is marked out of, by default. */
92 public $defaultmark = 1;
93
94 /** @var integer How many question numbers this question consumes. */
95 public $length = 1;
96
97 /** @var number penalty factor of this question. */
98 public $penalty = 0;
99
100 /** @var string unique identifier of this question. */
101 public $stamp;
102
103 /** @var string unique identifier of this version of this question. */
104 public $version;
105
106 /** @var boolean whethre this question has been deleted/hidden in the question bank. */
107 public $hidden = 0;
108
109 /** @var integer timestamp when this question was created. */
110 public $timecreated;
111
112 /** @var integer timestamp when this question was modified. */
113 public $timemodified;
114
115 /** @var integer userid of the use who created this question. */
116 public $createdby;
117
118 /** @var integer userid of the use who modified this question. */
119 public $modifiedby;
120
121 /** @var array of question_hints. */
122 public $hints = array();
123
124 /**
125 * Constructor. Normally to get a question, you call
126 * {@link question_bank::load_question()}, but questions can be created
127 * directly, for example in unit test code.
128 * @return unknown_type
129 */
130 public function __construct() {
131 }
132
133 /**
134 * @return the name of the question type (for example multichoice) that this
135 * question is.
136 */
137 public function get_type_name() {
138 return $this->qtype->name();
139 }
140
141 /**
142 * Creat the appropriate behaviour for an attempt at this quetsion,
143 * given the desired (archetypal) behaviour.
144 *
145 * This default implementation will suit most normal graded questions.
146 *
147 * If your question is of a patricular type, then it may need to do something
148 * different. For example, if your question can only be graded manually, then
149 * it should probably return a manualgraded behaviour, irrespective of
150 * what is asked for.
151 *
152 * If your question wants to do somthing especially complicated is some situations,
153 * then you may wish to return a particular behaviour related to the
154 * one asked for. For example, you migth want to return a
155 * qbehaviour_interactive_adapted_for_myqtype.
156 *
c4efeb2b 157 * @param question_attempt $qa the attempt we are creating a behaviour for.
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158 * @param string $preferredbehaviour the requested type of behaviour.
159 * @return question_behaviour the new behaviour object.
160 */
161 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
162 return question_engine::make_archetypal_behaviour($preferredbehaviour, $qa);
163 }
164
165 /**
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166 * Start a new attempt at this question, storing any information that will
167 * be needed later in the step.
d1b7e03d 168 *
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169 * This is where the question can do any initialisation required on a
170 * per-attempt basis. For example, this is where the multiple choice
171 * question type randomly shuffles the choices (if that option is set).
d1b7e03d 172 *
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173 * Any information about how the question has been set up for this attempt
174 * should be stored in the $step, by calling $step->set_qt_var(...).
175 *
176 * @param question_attempt_step The first step of the {@link question_attempt}
177 * being started. Can be used to store state.
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178 * @param int $varant which variant of this question to start. Will be between
179 * 1 and {@link get_num_variants()} inclusive.
ef31a283 180 */
1da821bb 181 public function start_attempt(question_attempt_step $step, $variant) {
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182 }
183
184 /**
185 * When an in-progress {@link question_attempt} is re-loaded from the
186 * database, this method is called so that the question can re-initialise
187 * its internal state as needed by this attempt.
188 *
189 * For example, the multiple choice question type needs to set the order
190 * of the choices to the order that was set up when start_attempt was called
191 * originally. All the information required to do this should be in the
192 * $step object, which is the first step of the question_attempt being loaded.
193 *
194 * @param question_attempt_step The first step of the {@link question_attempt}
195 * being loaded.
d1b7e03d 196 */
ef31a283 197 public function apply_attempt_state(question_attempt_step $step) {
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198 }
199
200 /**
201 * Generate a brief, plain-text, summary of this question. This is used by
202 * various reports. This should show the particular variant of the question
203 * as presented to students. For example, the calculated quetsion type would
204 * fill in the particular numbers that were presented to the student.
205 * This method will return null if such a summary is not possible, or
206 * inappropriate.
207 * @return string|null a plain text summary of this question.
208 */
ec3d4ef5 209 public function get_question_summary() {
22cebed5 210 return $this->html_to_text($this->questiontext, $this->questiontextformat);
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211 }
212
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213 /**
214 * @return int the number of vaiants that this question has.
215 */
216 public function get_num_variants() {
217 return 1;
218 }
219
220 /**
221 * @return string that can be used to seed the pseudo-random selection of a
222 * variant.
223 */
224 public function get_variants_selection_seed() {
225 return $this->stamp;
226 }
227
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228 /**
229 * Some questions can return a negative mark if the student gets it wrong.
230 *
231 * This method returns the lowest mark the question can return, on the
232 * fraction scale. that is, where the maximum possible mark is 1.0.
233 *
4e3d8293 234 * @return float minimum fraction this question will ever return.
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235 */
236 public function get_min_fraction() {
237 return 0;
238 }
239
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240 /**
241 * Some questions can return a mark greater than the maximum.
242 *
243 * This method returns the lowest highest the question can return, on the
244 * fraction scale. that is, where the nominal maximum mark is 1.0.
245 *
246 * @return float maximum fraction this question will ever return.
247 */
248 public function get_max_fraction() {
249 return 1;
250 }
251
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252 /**
253 * Given a response, rest the parts that are wrong.
254 * @param array $response a response
255 * @return array a cleaned up response with the wrong bits reset.
256 */
257 public function clear_wrong_from_response(array $response) {
258 return array();
259 }
260
261 /**
262 * Return the number of subparts of this response that are right.
263 * @param array $response a response
264 * @return array with two elements, the number of correct subparts, and
265 * the total number of subparts.
266 */
267 public function get_num_parts_right(array $response) {
268 return array(null, null);
269 }
270
271 /**
b36d2d06 272 * @param moodle_page the page we are outputting to.
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273 * @return qtype_renderer the renderer to use for outputting this question.
274 */
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275 public function get_renderer(moodle_page $page) {
276 return $page->get_renderer($this->qtype->plugin_name());
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277 }
278
279 /**
280 * What data may be included in the form submission when a student submits
281 * this question in its current state?
282 *
283 * This information is used in calls to optional_param. The parameter name
284 * has {@link question_attempt::get_field_prefix()} automatically prepended.
285 *
286 * @return array|string variable name => PARAM_... constant, or, as a special case
287 * that should only be used in unavoidable, the constant question_attempt::USE_RAW_DATA
288 * meaning take all the raw submitted data belonging to this question.
289 */
290 public abstract function get_expected_data();
291
292 /**
293 * What data would need to be submitted to get this question correct.
294 * If there is more than one correct answer, this method should just
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295 * return one possibility. If it is not possible to compute a correct
296 * response, this method should return null.
d1b7e03d 297 *
da22c012 298 * @return array|null parameter name => value.
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299 */
300 public abstract function get_correct_response();
301
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302
303 /**
304 * Passed an array of data representing a student response this function transforms the array to a response array as would be
305 * returned from the html form for this question instance.
306 *
307 * In most cases the array will just be returned as is. Some question types will need to transform the keys of the array in
308 * as the meaning of the keys in the html form is deliberately obfuscated so that someone looking at the html does not get an
309 * advantage.
310 *
311 * @param array $simulatedresponse an array of data representing a student response
312 * @return array a response array as would be returned from the html form (but without prefixes)
313 */
314 public function prepare_simulated_post_data($simulatedresponse) {
315 return $simulatedresponse;
316 }
317
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318 /**
319 * Apply {@link format_text()} to some content with appropriate settings for
320 * this question.
321 *
322 * @param string $text some content that needs to be output.
22cebed5 323 * @param int $format the FORMAT_... constant.
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324 * @param question_attempt $qa the question attempt.
325 * @param string $component used for rewriting file area URLs.
326 * @param string $filearea used for rewriting file area URLs.
f7970e3c 327 * @param bool $clean Whether the HTML needs to be cleaned. Generally,
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328 * parts of the question do not need to be cleaned, and student input does.
329 * @return string the text formatted for output by format_text.
330 */
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331 public function format_text($text, $format, $qa, $component, $filearea, $itemid,
332 $clean = false) {
0ff4bd08 333 $formatoptions = new stdClass();
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334 $formatoptions->noclean = !$clean;
335 $formatoptions->para = false;
7a719748 336 $text = $qa->rewrite_pluginfile_urls($text, $component, $filearea, $itemid);
22cebed5 337 return format_text($text, $format, $formatoptions);
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338 }
339
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340 /**
341 * Convert some part of the question text to plain text. This might be used,
342 * for example, by get_response_summary().
343 * @param string $text The HTML to reduce to plain text.
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344 * @param int $format the FORMAT_... constant.
345 * @return string the equivalent plain text.
ec3d4ef5 346 */
22cebed5 347 public function html_to_text($text, $format) {
e2b388c1 348 return question_utils::to_plain_text($text, $format);
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349 }
350
d1b7e03d 351 /** @return the result of applying {@link format_text()} to the question text. */
2b7da645 352 public function format_questiontext($qa) {
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353 return $this->format_text($this->questiontext, $this->questiontextformat,
354 $qa, 'question', 'questiontext', $this->id);
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355 }
356
357 /** @return the result of applying {@link format_text()} to the general feedback. */
2b7da645 358 public function format_generalfeedback($qa) {
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359 return $this->format_text($this->generalfeedback, $this->generalfeedbackformat,
360 $qa, 'question', 'generalfeedback', $this->id);
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361 }
362
363 /**
364 * Checks whether the users is allow to be served a particular file.
93cadb1e 365 * @param question_attempt $qa the question attempt being displayed.
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366 * @param question_display_options $options the options that control display of the question.
367 * @param string $component the name of the component we are serving files for.
368 * @param string $filearea the name of the file area.
369 * @param array $args the remaining bits of the file path.
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370 * @param bool $forcedownload whether the user must be forced to download the file.
371 * @return bool true if the user can access this file.
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372 */
373 public function check_file_access($qa, $options, $component, $filearea, $args, $forcedownload) {
374 if ($component == 'question' && $filearea == 'questiontext') {
375 // Question text always visible.
376 return true;
377
378 } else if ($component == 'question' && $filearea == 'generalfeedback') {
379 return $options->generalfeedback;
380
381 } else {
382 // Unrecognised component or filearea.
383 return false;
384 }
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385 }
386}
387
388
389/**
390 * This class represents a 'question' that actually does not allow the student
391 * to respond, like the description 'question' type.
392 *
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393 * @copyright 2009 The Open University
394 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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395 */
396class question_information_item extends question_definition {
397 public function __construct() {
398 parent::__construct();
399 $this->defaultmark = 0;
400 $this->penalty = 0;
401 $this->length = 0;
402 }
403
404 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
f3460297 405 return question_engine::make_behaviour('informationitem', $qa, $preferredbehaviour);
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406 }
407
408 public function get_expected_data() {
409 return array();
410 }
411
412 public function get_correct_response() {
413 return array();
414 }
415
416 public function get_question_summary() {
417 return null;
418 }
419}
420
421
422/**
423 * Interface that a {@link question_definition} must implement to be usable by
424 * the manual graded behaviour.
425 *
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426 * @copyright 2009 The Open University
427 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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428 */
429interface question_manually_gradable {
430 /**
431 * Used by many of the behaviours, to work out whether the student's
432 * response to the question is complete. That is, whether the question attempt
433 * should move to the COMPLETE or INCOMPLETE state.
434 *
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435 * @param array $response responses, as returned by
436 * {@link question_attempt_step::get_qt_data()}.
f7970e3c 437 * @return bool whether this response is a complete answer to this question.
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438 */
439 public function is_complete_response(array $response);
440
441 /**
442 * Use by many of the behaviours to determine whether the student's
443 * response has changed. This is normally used to determine that a new set
444 * of responses can safely be discarded.
445 *
446 * @param array $prevresponse the responses previously recorded for this question,
447 * as returned by {@link question_attempt_step::get_qt_data()}
448 * @param array $newresponse the new responses, in the same format.
f7970e3c 449 * @return bool whether the two sets of responses are the same - that is
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450 * whether the new set of responses can safely be discarded.
451 */
452 public function is_same_response(array $prevresponse, array $newresponse);
453
454 /**
455 * Produce a plain text summary of a response.
456 * @param $response a response, as might be passed to {@link grade_response()}.
457 * @return string a plain text summary of that response, that could be used in reports.
458 */
459 public function summarise_response(array $response);
460
461 /**
462 * Categorise the student's response according to the categories defined by
463 * get_possible_responses.
464 * @param $response a response, as might be passed to {@link grade_response()}.
465 * @return array subpartid => {@link question_classified_response} objects.
466 * returns an empty array if no analysis is possible.
467 */
468 public function classify_response(array $response);
469}
470
471
472/**
473 * This class is used in the return value from
474 * {@link question_manually_gradable::classify_response()}.
475 *
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476 * @copyright 2010 The Open University
477 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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478 */
479class question_classified_response {
480 /**
481 * @var string the classification of this response the student gave to this
482 * part of the question. Must match one of the responseclasses returned by
483 * {@link question_type::get_possible_responses()}.
484 */
485 public $responseclassid;
486 /** @var string the actual response the student gave to this part. */
487 public $response;
488 /** @var number the fraction this part of the response earned. */
489 public $fraction;
490 /**
491 * Constructor, just an easy way to set the fields.
492 * @param string $responseclassid see the field descriptions above.
493 * @param string $response see the field descriptions above.
494 * @param number $fraction see the field descriptions above.
495 */
496 public function __construct($responseclassid, $response, $fraction) {
497 $this->responseclassid = $responseclassid;
498 $this->response = $response;
499 $this->fraction = $fraction;
500 }
501
502 public static function no_response() {
e5b0920e 503 return new question_classified_response(null, get_string('noresponse', 'question'), null);
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504 }
505}
506
507
508/**
509 * Interface that a {@link question_definition} must implement to be usable by
510 * the various automatic grading behaviours.
511 *
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512 * @copyright 2009 The Open University
513 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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514 */
515interface question_automatically_gradable extends question_manually_gradable {
516 /**
517 * Use by many of the behaviours to determine whether the student
518 * has provided enough of an answer for the question to be graded automatically,
519 * or whether it must be considered aborted.
520 *
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521 * @param array $response responses, as returned by
522 * {@link question_attempt_step::get_qt_data()}.
f7970e3c 523 * @return bool whether this response can be graded.
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524 */
525 public function is_gradable_response(array $response);
526
527 /**
528 * In situations where is_gradable_response() returns false, this method
529 * should generate a description of what the problem is.
530 * @return string the message.
531 */
532 public function get_validation_error(array $response);
533
534 /**
eaeb6b51 535 * Grade a response to the question, returning a fraction between
4e3d8293 536 * get_min_fraction() and get_max_fraction(), and the corresponding {@link question_state}
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537 * right, partial or wrong.
538 * @param array $response responses, as returned by
539 * {@link question_attempt_step::get_qt_data()}.
4e3d8293 540 * @return array (float, integer) the fraction, and the state.
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541 */
542 public function grade_response(array $response);
543
544 /**
545 * Get one of the question hints. The question_attempt is passed in case
546 * the question type wants to do something complex. For example, the
547 * multiple choice with multiple responses question type will turn off most
548 * of the hint options if the student has selected too many opitions.
f7970e3c 549 * @param int $hintnumber Which hint to display. Indexed starting from 0
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550 * @param question_attempt $qa The question_attempt.
551 */
552 public function get_hint($hintnumber, question_attempt $qa);
553
554 /**
555 * Generate a brief, plain-text, summary of the correct answer to this question.
556 * This is used by various reports, and can also be useful when testing.
557 * This method will return null if such a summary is not possible, or
558 * inappropriate.
559 * @return string|null a plain text summary of the right answer to this question.
560 */
561 public function get_right_answer_summary();
562}
563
564
565/**
566 * Interface that a {@link question_definition} must implement to be usable by
567 * the interactivecountback behaviour.
568 *
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569 * @copyright 2010 The Open University
570 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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571 */
572interface question_automatically_gradable_with_countback extends question_automatically_gradable {
573 /**
574 * Work out a final grade for this attempt, taking into account all the
575 * tries the student made.
576 * @param array $responses the response for each try. Each element of this
577 * array is a response array, as would be passed to {@link grade_response()}.
578 * There may be between 1 and $totaltries responses.
f7970e3c 579 * @param int $totaltries The maximum number of tries allowed.
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580 * @return numeric the fraction that should be awarded for this
581 * sequence of response.
582 */
583 public function compute_final_grade($responses, $totaltries);
584}
585
586
587/**
588 * This class represents a real question. That is, one that is not a
589 * {@link question_information_item}.
590 *
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591 * @copyright 2009 The Open University
592 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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593 */
594abstract class question_with_responses extends question_definition
595 implements question_manually_gradable {
c7df5006 596 public function classify_response(array $response) {
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597 return array();
598 }
599}
600
601
602/**
603 * This class represents a question that can be graded automatically.
604 *
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605 * @copyright 2009 The Open University
606 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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607 */
608abstract class question_graded_automatically extends question_with_responses
609 implements question_automatically_gradable {
610 /** @var Some question types have the option to show the number of sub-parts correct. */
611 public $shownumcorrect = false;
612
613 public function is_gradable_response(array $response) {
614 return $this->is_complete_response($response);
615 }
616
617 public function get_right_answer_summary() {
618 $correctresponse = $this->get_correct_response();
619 if (empty($correctresponse)) {
620 return null;
621 }
622 return $this->summarise_response($correctresponse);
623 }
624
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625 /**
626 * Check a request for access to a file belonging to a combined feedback field.
627 * @param question_attempt $qa the question attempt being displayed.
628 * @param question_display_options $options the options that control display of the question.
629 * @param string $filearea the name of the file area.
f7970e3c 630 * @return bool whether access to the file should be allowed.
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631 */
632 protected function check_combined_feedback_file_access($qa, $options, $filearea) {
633 $state = $qa->get_state();
634
635 if (!$state->is_finished()) {
636 $response = $qa->get_last_qt_data();
637 if (!$this->is_gradable_response($response)) {
638 return false;
639 }
640 list($notused, $state) = $this->grade_response($response);
641 }
642
643 return $options->feedback && $state->get_feedback_class() . 'feedback' == $filearea;
644 }
645
646 /**
647 * Check a request for access to a file belonging to a hint.
648 * @param question_attempt $qa the question attempt being displayed.
649 * @param question_display_options $options the options that control display of the question.
650 * @param array $args the remaining bits of the file path.
f7970e3c 651 * @return bool whether access to the file should be allowed.
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652 */
653 protected function check_hint_file_access($qa, $options, $args) {
654 if (!$options->feedback) {
655 return false;
656 }
657 $hint = $qa->get_applicable_hint();
3d9645ae 658 $hintid = reset($args); // Itemid is hint id.
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659 return $hintid == $hint->id;
660 }
661
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662 public function get_hint($hintnumber, question_attempt $qa) {
663 if (!isset($this->hints[$hintnumber])) {
664 return null;
665 }
666 return $this->hints[$hintnumber];
667 }
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668
669 public function format_hint(question_hint $hint, question_attempt $qa) {
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670 return $this->format_text($hint->hint, $hint->hintformat, $qa,
671 'question', 'hint', $hint->id);
7a719748 672 }
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673}
674
675
676/**
677 * This class represents a question that can be graded automatically with
678 * countback grading in interactive mode.
679 *
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680 * @copyright 2010 The Open University
681 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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682 */
683abstract class question_graded_automatically_with_countback
684 extends question_graded_automatically
685 implements question_automatically_gradable_with_countback {
686
687 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
688 if ($preferredbehaviour == 'interactive') {
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689 return question_engine::make_behaviour('interactivecountback',
690 $qa, $preferredbehaviour);
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691 }
692 return question_engine::make_archetypal_behaviour($preferredbehaviour, $qa);
693 }
694}
695
696
697/**
698 * This class represents a question that can be graded automatically by using
699 * a {@link question_grading_strategy}.
700 *
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701 * @copyright 2009 The Open University
702 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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703 */
704abstract class question_graded_by_strategy extends question_graded_automatically {
705 /** @var question_grading_strategy the strategy to use for grading. */
706 protected $gradingstrategy;
707
708 /** @param question_grading_strategy $strategy the strategy to use for grading. */
709 public function __construct(question_grading_strategy $strategy) {
710 parent::__construct();
711 $this->gradingstrategy = $strategy;
712 }
713
714 public function get_correct_response() {
715 $answer = $this->get_correct_answer();
716 if (!$answer) {
717 return array();
718 }
719
720 return array('answer' => $answer->answer);
721 }
722
723 /**
724 * Get an answer that contains the feedback and fraction that should be
725 * awarded for this resonse.
726 * @param array $response a response.
727 * @return question_answer the matching answer.
728 */
729 public function get_matching_answer(array $response) {
730 return $this->gradingstrategy->grade($response);
731 }
732
733 /**
734 * @return question_answer an answer that contains the a response that would
735 * get full marks.
736 */
737 public function get_correct_answer() {
738 return $this->gradingstrategy->get_correct_answer();
739 }
740
741 public function grade_response(array $response) {
742 $answer = $this->get_matching_answer($response);
743 if ($answer) {
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744 return array($answer->fraction,
745 question_state::graded_state_for_fraction($answer->fraction));
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746 } else {
747 return array(0, question_state::$gradedwrong);
748 }
749 }
750
751 public function classify_response(array $response) {
752 if (empty($response['answer'])) {
753 return array($this->id => question_classified_response::no_response());
754 }
755
756 $ans = $this->get_matching_answer($response);
757 if (!$ans) {
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758 return array($this->id => new question_classified_response(
759 0, $response['answer'], 0));
d1b7e03d 760 }
24400682 761
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762 return array($this->id => new question_classified_response(
763 $ans->id, $response['answer'], $ans->fraction));
764 }
765}
766
767
768/**
769 * Class to represent a question answer, loaded from the question_answers table
770 * in the database.
771 *
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772 * @copyright 2009 The Open University
773 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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774 */
775class question_answer {
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776 /** @var integer the answer id. */
777 public $id;
778
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779 /** @var string the answer. */
780 public $answer;
781
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782 /** @var integer one of the FORMAT_... constans. */
783 public $answerformat = FORMAT_PLAIN;
784
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785 /** @var number the fraction this answer is worth. */
786 public $fraction;
787
788 /** @var string the feedback for this answer. */
789 public $feedback;
790
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791 /** @var integer one of the FORMAT_... constans. */
792 public $feedbackformat;
793
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794 /**
795 * Constructor.
22cebed5 796 * @param int $id the answer.
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797 * @param string $answer the answer.
798 * @param number $fraction the fraction this answer is worth.
799 * @param string $feedback the feedback for this answer.
22cebed5 800 * @param int $feedbackformat the format of the feedback.
d1b7e03d 801 */
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802 public function __construct($id, $answer, $fraction, $feedback, $feedbackformat) {
803 $this->id = $id;
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804 $this->answer = $answer;
805 $this->fraction = $fraction;
806 $this->feedback = $feedback;
5f7cfba7 807 $this->feedbackformat = $feedbackformat;
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808 }
809}
810
811
812/**
813 * Class to represent a hint associated with a question.
814 * Used by iteractive mode, etc. A question has an array of these.
815 *
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816 * @copyright 2010 The Open University
817 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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818 */
819class question_hint {
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820 /** @var integer The hint id. */
821 public $id;
822 /** @var string The feedback hint to be shown. */
d1b7e03d 823 public $hint;
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824 /** @var integer The corresponding text FORMAT_... type. */
825 public $hintformat;
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826
827 /**
828 * Constructor.
f7970e3c 829 * @param int the hint id from the database.
d1b7e03d 830 * @param string $hint The hint text
f7970e3c 831 * @param int the corresponding text FORMAT_... type.
d1b7e03d 832 */
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833 public function __construct($id, $hint, $hintformat) {
834 $this->id = $id;
d1b7e03d 835 $this->hint = $hint;
7a719748 836 $this->hintformat = $hintformat;
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837 }
838
839 /**
840 * Create a basic hint from a row loaded from the question_hints table in the database.
841 * @param object $row with $row->hint set.
842 * @return question_hint
843 */
844 public static function load_from_record($row) {
7a719748 845 return new question_hint($row->id, $row->hint, $row->hintformat);
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846 }
847
848 /**
849 * Adjust this display options according to the hint settings.
850 * @param question_display_options $options
851 */
852 public function adjust_display_options(question_display_options $options) {
853 // Do nothing.
854 }
855}
856
857
858/**
859 * An extension of {@link question_hint} for questions like match and multiple
860 * choice with multile answers, where there are options for whether to show the
861 * number of parts right at each stage, and to reset the wrong parts.
862 *
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863 * @copyright 2010 The Open University
864 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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865 */
866class question_hint_with_parts extends question_hint {
867 /** @var boolean option to show the number of sub-parts of the question that were right. */
868 public $shownumcorrect;
869
870 /** @var boolean option to clear the parts of the question that were wrong on retry. */
871 public $clearwrong;
872
873 /**
874 * Constructor.
f7970e3c 875 * @param int the hint id from the database.
d1b7e03d 876 * @param string $hint The hint text
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877 * @param int the corresponding text FORMAT_... type.
878 * @param bool $shownumcorrect whether the number of right parts should be shown
879 * @param bool $clearwrong whether the wrong parts should be reset.
d1b7e03d 880 */
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881 public function __construct($id, $hint, $hintformat, $shownumcorrect, $clearwrong) {
882 parent::__construct($id, $hint, $hintformat);
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883 $this->shownumcorrect = $shownumcorrect;
884 $this->clearwrong = $clearwrong;
885 }
886
887 /**
888 * Create a basic hint from a row loaded from the question_hints table in the database.
889 * @param object $row with $row->hint, ->shownumcorrect and ->clearwrong set.
890 * @return question_hint_with_parts
891 */
892 public static function load_from_record($row) {
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893 return new question_hint_with_parts($row->id, $row->hint, $row->hintformat,
894 $row->shownumcorrect, $row->clearwrong);
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895 }
896
897 public function adjust_display_options(question_display_options $options) {
898 parent::adjust_display_options($options);
899 if ($this->clearwrong) {
900 $options->clearwrong = true;
901 }
902 $options->numpartscorrect = $this->shownumcorrect;
903 }
904}
905
906
907/**
908 * This question_grading_strategy interface. Used to share grading code between
909 * questions that that subclass {@link question_graded_by_strategy}.
910 *
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911 * @copyright 2009 The Open University
912 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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913 */
914interface question_grading_strategy {
915 /**
916 * Return a question answer that describes the outcome (fraction and feeback)
917 * for a particular respons.
918 * @param array $response the response.
919 * @return question_answer the answer describing the outcome.
920 */
921 public function grade(array $response);
922
923 /**
924 * @return question_answer an answer that contains the a response that would
925 * get full marks.
926 */
927 public function get_correct_answer();
928}
929
930
931/**
932 * This interface defines the methods that a {@link question_definition} must
933 * implement if it is to be graded by the
934 * {@link question_first_matching_answer_grading_strategy}.
935 *
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936 * @copyright 2009 The Open University
937 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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938 */
939interface question_response_answer_comparer {
940 /** @return array of {@link question_answers}. */
941 public function get_answers();
942
943 /**
944 * @param array $response the response.
945 * @param question_answer $answer an answer.
f7970e3c 946 * @return bool whether the response matches the answer.
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947 */
948 public function compare_response_with_answer(array $response, question_answer $answer);
949}
950
951
952/**
953 * This grading strategy is used by question types like shortanswer an numerical.
954 * It gets a list of possible answers from the question, and returns the first one
955 * that matches the given response. It returns the first answer with fraction 1.0
956 * when asked for the correct answer.
957 *
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958 * @copyright 2009 The Open University
959 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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960 */
961class question_first_matching_answer_grading_strategy implements question_grading_strategy {
962 /**
963 * @var question_response_answer_comparer (presumably also a
964 * {@link question_definition}) the question we are doing the grading for.
965 */
966 protected $question;
967
968 /**
969 * @param question_response_answer_comparer $question (presumably also a
970 * {@link question_definition}) the question we are doing the grading for.
971 */
972 public function __construct(question_response_answer_comparer $question) {
973 $this->question = $question;
974 }
975
976 public function grade(array $response) {
977 foreach ($this->question->get_answers() as $aid => $answer) {
978 if ($this->question->compare_response_with_answer($response, $answer)) {
979 $answer->id = $aid;
980 return $answer;
981 }
982 }
983 return null;
984 }
985
986 public function get_correct_answer() {
987 foreach ($this->question->get_answers() as $answer) {
988 $state = question_state::graded_state_for_fraction($answer->fraction);
989 if ($state == question_state::$gradedright) {
990 return $answer;
991 }
992 }
993 return null;
994 }
01c898ec 995}