MDL-57587 question file access: fix regression caused by MDL-53744
[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 /**
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304 * Takes an array of values representing a student response represented in a way that is understandable by a human and
305 * transforms that to the response as the POST values returned from the HTML form that takes the student response during a
306 * student attempt. Primarily this is used when reading csv values from a file of student responses in order to be able to
307 * simulate the student interaction with a quiz.
388f0473 308 *
58794ac9 309 * In most cases the array will just be returned as is. Some question types will need to transform the keys of the array,
388f0473 310 * as the meaning of the keys in the html form is deliberately obfuscated so that someone looking at the html does not get an
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311 * advantage. The values that represent the response might also be changed in order to more meaningful to a human.
312 *
313 * See the examples of question types that have overridden this in core and also see the csv files of simulated student
314 * responses used in unit tests in :
315 * - mod/quiz/tests/fixtures/stepsXX.csv
316 * - mod/quiz/report/responses/tests/fixtures/steps00.csv
317 * - mod/quiz/report/statistics/tests/fixtures/stepsXX.csv
318 *
319 * Also see {@link https://github.com/jamiepratt/moodle-quiz_simulate}, a quiz report plug in for uploading and downloading
320 * student responses as csv files.
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321 *
322 * @param array $simulatedresponse an array of data representing a student response
323 * @return array a response array as would be returned from the html form (but without prefixes)
324 */
325 public function prepare_simulated_post_data($simulatedresponse) {
326 return $simulatedresponse;
327 }
328
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329 /**
330 * Does the opposite of {@link prepare_simulated_post_data}.
331 *
332 * This takes a student response (the POST values returned from the HTML form that takes the student response during a
333 * student attempt) it then represents it in a way that is understandable by a human.
334 *
335 * Primarily this is used when creating a file of csv from real student responses in order later to be able to
336 * simulate the same student interaction with a quiz later.
337 *
338 * @param string[] $realresponse the response array as was returned from the form during a student attempt (without prefixes).
339 * @return string[] an array of data representing a student response.
340 */
341 public function get_student_response_values_for_simulation($realresponse) {
342 return $realresponse;
343 }
344
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345 /**
346 * Apply {@link format_text()} to some content with appropriate settings for
347 * this question.
348 *
349 * @param string $text some content that needs to be output.
22cebed5 350 * @param int $format the FORMAT_... constant.
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351 * @param question_attempt $qa the question attempt.
352 * @param string $component used for rewriting file area URLs.
353 * @param string $filearea used for rewriting file area URLs.
f7970e3c 354 * @param bool $clean Whether the HTML needs to be cleaned. Generally,
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355 * parts of the question do not need to be cleaned, and student input does.
356 * @return string the text formatted for output by format_text.
357 */
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358 public function format_text($text, $format, $qa, $component, $filearea, $itemid,
359 $clean = false) {
0ff4bd08 360 $formatoptions = new stdClass();
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361 $formatoptions->noclean = !$clean;
362 $formatoptions->para = false;
7a719748 363 $text = $qa->rewrite_pluginfile_urls($text, $component, $filearea, $itemid);
22cebed5 364 return format_text($text, $format, $formatoptions);
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365 }
366
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367 /**
368 * Convert some part of the question text to plain text. This might be used,
369 * for example, by get_response_summary().
370 * @param string $text The HTML to reduce to plain text.
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371 * @param int $format the FORMAT_... constant.
372 * @return string the equivalent plain text.
ec3d4ef5 373 */
22cebed5 374 public function html_to_text($text, $format) {
e2b388c1 375 return question_utils::to_plain_text($text, $format);
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376 }
377
d1b7e03d 378 /** @return the result of applying {@link format_text()} to the question text. */
2b7da645 379 public function format_questiontext($qa) {
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380 return $this->format_text($this->questiontext, $this->questiontextformat,
381 $qa, 'question', 'questiontext', $this->id);
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382 }
383
384 /** @return the result of applying {@link format_text()} to the general feedback. */
2b7da645 385 public function format_generalfeedback($qa) {
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386 return $this->format_text($this->generalfeedback, $this->generalfeedbackformat,
387 $qa, 'question', 'generalfeedback', $this->id);
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388 }
389
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390 /**
391 * Take some HTML that should probably already be a single line, like a
392 * multiple choice choice, or the corresponding feedback, and make it so that
393 * it is suitable to go in a place where the HTML must be inline, like inside a <p> tag.
394 * @param string $html to HTML to fix up.
395 * @return string the fixed HTML.
396 */
397 public function make_html_inline($html) {
398 $html = preg_replace('~\s*<p>\s*~u', '', $html);
399 $html = preg_replace('~\s*</p>\s*~u', '<br />', $html);
400 $html = preg_replace('~(<br\s*/?>)+$~u', '', $html);
401 return trim($html);
402 }
403
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404 /**
405 * Checks whether the users is allow to be served a particular file.
93cadb1e 406 * @param question_attempt $qa the question attempt being displayed.
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407 * @param question_display_options $options the options that control display of the question.
408 * @param string $component the name of the component we are serving files for.
409 * @param string $filearea the name of the file area.
410 * @param array $args the remaining bits of the file path.
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411 * @param bool $forcedownload whether the user must be forced to download the file.
412 * @return bool true if the user can access this file.
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413 */
414 public function check_file_access($qa, $options, $component, $filearea, $args, $forcedownload) {
415 if ($component == 'question' && $filearea == 'questiontext') {
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416 // Question text always visible, but check it is the right question id.
417 return $args[0] == $this->id;
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418
419 } else if ($component == 'question' && $filearea == 'generalfeedback') {
cf0b9432 420 return $options->generalfeedback && $args[0] == $this->id;
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421
422 } else {
423 // Unrecognised component or filearea.
424 return false;
425 }
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426 }
427}
428
429
430/**
431 * This class represents a 'question' that actually does not allow the student
432 * to respond, like the description 'question' type.
433 *
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434 * @copyright 2009 The Open University
435 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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436 */
437class question_information_item extends question_definition {
438 public function __construct() {
439 parent::__construct();
440 $this->defaultmark = 0;
441 $this->penalty = 0;
442 $this->length = 0;
443 }
444
445 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
f3460297 446 return question_engine::make_behaviour('informationitem', $qa, $preferredbehaviour);
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447 }
448
449 public function get_expected_data() {
450 return array();
451 }
452
453 public function get_correct_response() {
454 return array();
455 }
456
457 public function get_question_summary() {
458 return null;
459 }
460}
461
462
463/**
464 * Interface that a {@link question_definition} must implement to be usable by
465 * the manual graded behaviour.
466 *
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467 * @copyright 2009 The Open University
468 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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469 */
470interface question_manually_gradable {
471 /**
472 * Used by many of the behaviours, to work out whether the student's
473 * response to the question is complete. That is, whether the question attempt
474 * should move to the COMPLETE or INCOMPLETE state.
475 *
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476 * @param array $response responses, as returned by
477 * {@link question_attempt_step::get_qt_data()}.
f7970e3c 478 * @return bool whether this response is a complete answer to this question.
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479 */
480 public function is_complete_response(array $response);
481
482 /**
483 * Use by many of the behaviours to determine whether the student's
484 * response has changed. This is normally used to determine that a new set
485 * of responses can safely be discarded.
486 *
487 * @param array $prevresponse the responses previously recorded for this question,
488 * as returned by {@link question_attempt_step::get_qt_data()}
489 * @param array $newresponse the new responses, in the same format.
f7970e3c 490 * @return bool whether the two sets of responses are the same - that is
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491 * whether the new set of responses can safely be discarded.
492 */
493 public function is_same_response(array $prevresponse, array $newresponse);
494
495 /**
496 * Produce a plain text summary of a response.
497 * @param $response a response, as might be passed to {@link grade_response()}.
498 * @return string a plain text summary of that response, that could be used in reports.
499 */
500 public function summarise_response(array $response);
501
502 /**
503 * Categorise the student's response according to the categories defined by
504 * get_possible_responses.
505 * @param $response a response, as might be passed to {@link grade_response()}.
506 * @return array subpartid => {@link question_classified_response} objects.
507 * returns an empty array if no analysis is possible.
508 */
509 public function classify_response(array $response);
510}
511
512
513/**
514 * This class is used in the return value from
515 * {@link question_manually_gradable::classify_response()}.
516 *
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517 * @copyright 2010 The Open University
518 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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519 */
520class question_classified_response {
521 /**
522 * @var string the classification of this response the student gave to this
523 * part of the question. Must match one of the responseclasses returned by
524 * {@link question_type::get_possible_responses()}.
525 */
526 public $responseclassid;
527 /** @var string the actual response the student gave to this part. */
528 public $response;
529 /** @var number the fraction this part of the response earned. */
530 public $fraction;
531 /**
532 * Constructor, just an easy way to set the fields.
533 * @param string $responseclassid see the field descriptions above.
534 * @param string $response see the field descriptions above.
535 * @param number $fraction see the field descriptions above.
536 */
537 public function __construct($responseclassid, $response, $fraction) {
538 $this->responseclassid = $responseclassid;
539 $this->response = $response;
540 $this->fraction = $fraction;
541 }
542
543 public static function no_response() {
e5b0920e 544 return new question_classified_response(null, get_string('noresponse', 'question'), null);
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545 }
546}
547
548
549/**
550 * Interface that a {@link question_definition} must implement to be usable by
551 * the various automatic grading behaviours.
552 *
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553 * @copyright 2009 The Open University
554 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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555 */
556interface question_automatically_gradable extends question_manually_gradable {
557 /**
558 * Use by many of the behaviours to determine whether the student
559 * has provided enough of an answer for the question to be graded automatically,
560 * or whether it must be considered aborted.
561 *
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562 * @param array $response responses, as returned by
563 * {@link question_attempt_step::get_qt_data()}.
f7970e3c 564 * @return bool whether this response can be graded.
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565 */
566 public function is_gradable_response(array $response);
567
568 /**
569 * In situations where is_gradable_response() returns false, this method
570 * should generate a description of what the problem is.
571 * @return string the message.
572 */
573 public function get_validation_error(array $response);
574
575 /**
eaeb6b51 576 * Grade a response to the question, returning a fraction between
4e3d8293 577 * get_min_fraction() and get_max_fraction(), and the corresponding {@link question_state}
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578 * right, partial or wrong.
579 * @param array $response responses, as returned by
580 * {@link question_attempt_step::get_qt_data()}.
4e3d8293 581 * @return array (float, integer) the fraction, and the state.
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582 */
583 public function grade_response(array $response);
584
585 /**
586 * Get one of the question hints. The question_attempt is passed in case
587 * the question type wants to do something complex. For example, the
588 * multiple choice with multiple responses question type will turn off most
589 * of the hint options if the student has selected too many opitions.
f7970e3c 590 * @param int $hintnumber Which hint to display. Indexed starting from 0
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591 * @param question_attempt $qa The question_attempt.
592 */
593 public function get_hint($hintnumber, question_attempt $qa);
594
595 /**
596 * Generate a brief, plain-text, summary of the correct answer to this question.
597 * This is used by various reports, and can also be useful when testing.
598 * This method will return null if such a summary is not possible, or
599 * inappropriate.
600 * @return string|null a plain text summary of the right answer to this question.
601 */
602 public function get_right_answer_summary();
603}
604
605
606/**
607 * Interface that a {@link question_definition} must implement to be usable by
608 * the interactivecountback behaviour.
609 *
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610 * @copyright 2010 The Open University
611 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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612 */
613interface question_automatically_gradable_with_countback extends question_automatically_gradable {
614 /**
615 * Work out a final grade for this attempt, taking into account all the
616 * tries the student made.
617 * @param array $responses the response for each try. Each element of this
618 * array is a response array, as would be passed to {@link grade_response()}.
619 * There may be between 1 and $totaltries responses.
f7970e3c 620 * @param int $totaltries The maximum number of tries allowed.
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621 * @return numeric the fraction that should be awarded for this
622 * sequence of response.
623 */
624 public function compute_final_grade($responses, $totaltries);
625}
626
627
628/**
629 * This class represents a real question. That is, one that is not a
630 * {@link question_information_item}.
631 *
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632 * @copyright 2009 The Open University
633 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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634 */
635abstract class question_with_responses extends question_definition
636 implements question_manually_gradable {
c7df5006 637 public function classify_response(array $response) {
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638 return array();
639 }
640}
641
642
643/**
644 * This class represents a question that can be graded automatically.
645 *
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646 * @copyright 2009 The Open University
647 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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648 */
649abstract class question_graded_automatically extends question_with_responses
650 implements question_automatically_gradable {
651 /** @var Some question types have the option to show the number of sub-parts correct. */
652 public $shownumcorrect = false;
653
654 public function is_gradable_response(array $response) {
655 return $this->is_complete_response($response);
656 }
657
658 public function get_right_answer_summary() {
659 $correctresponse = $this->get_correct_response();
660 if (empty($correctresponse)) {
661 return null;
662 }
663 return $this->summarise_response($correctresponse);
664 }
665
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666 /**
667 * Check a request for access to a file belonging to a combined feedback field.
668 * @param question_attempt $qa the question attempt being displayed.
669 * @param question_display_options $options the options that control display of the question.
670 * @param string $filearea the name of the file area.
c28bfbef 671 * @param array $args the remaining bits of the file path.
f7970e3c 672 * @return bool whether access to the file should be allowed.
93cadb1e 673 */
c28bfbef 674 protected function check_combined_feedback_file_access($qa, $options, $filearea, $args = null) {
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675 $state = $qa->get_state();
676
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677 if ($args === null) {
678 debugging('You must pass $args as the fourth argument to check_combined_feedback_file_access.',
679 DEBUG_DEVELOPER);
680 $args = array($this->id); // Fake it for now, so the rest of this method works.
681 }
682
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683 if (!$state->is_finished()) {
684 $response = $qa->get_last_qt_data();
685 if (!$this->is_gradable_response($response)) {
686 return false;
687 }
688 list($notused, $state) = $this->grade_response($response);
689 }
690
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691 return $options->feedback && $state->get_feedback_class() . 'feedback' == $filearea &&
692 $args[0] == $this->id;
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693 }
694
695 /**
696 * Check a request for access to a file belonging to a hint.
697 * @param question_attempt $qa the question attempt being displayed.
698 * @param question_display_options $options the options that control display of the question.
699 * @param array $args the remaining bits of the file path.
f7970e3c 700 * @return bool whether access to the file should be allowed.
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701 */
702 protected function check_hint_file_access($qa, $options, $args) {
703 if (!$options->feedback) {
704 return false;
705 }
706 $hint = $qa->get_applicable_hint();
3d9645ae 707 $hintid = reset($args); // Itemid is hint id.
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708 return $hintid == $hint->id;
709 }
710
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711 public function get_hint($hintnumber, question_attempt $qa) {
712 if (!isset($this->hints[$hintnumber])) {
713 return null;
714 }
715 return $this->hints[$hintnumber];
716 }
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717
718 public function format_hint(question_hint $hint, question_attempt $qa) {
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719 return $this->format_text($hint->hint, $hint->hintformat, $qa,
720 'question', 'hint', $hint->id);
7a719748 721 }
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722}
723
724
725/**
726 * This class represents a question that can be graded automatically with
727 * countback grading in interactive mode.
728 *
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729 * @copyright 2010 The Open University
730 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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731 */
732abstract class question_graded_automatically_with_countback
733 extends question_graded_automatically
734 implements question_automatically_gradable_with_countback {
735
736 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
737 if ($preferredbehaviour == 'interactive') {
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738 return question_engine::make_behaviour('interactivecountback',
739 $qa, $preferredbehaviour);
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740 }
741 return question_engine::make_archetypal_behaviour($preferredbehaviour, $qa);
742 }
743}
744
745
746/**
747 * This class represents a question that can be graded automatically by using
748 * a {@link question_grading_strategy}.
749 *
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750 * @copyright 2009 The Open University
751 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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752 */
753abstract class question_graded_by_strategy extends question_graded_automatically {
754 /** @var question_grading_strategy the strategy to use for grading. */
755 protected $gradingstrategy;
756
757 /** @param question_grading_strategy $strategy the strategy to use for grading. */
758 public function __construct(question_grading_strategy $strategy) {
759 parent::__construct();
760 $this->gradingstrategy = $strategy;
761 }
762
763 public function get_correct_response() {
764 $answer = $this->get_correct_answer();
765 if (!$answer) {
766 return array();
767 }
768
769 return array('answer' => $answer->answer);
770 }
771
772 /**
773 * Get an answer that contains the feedback and fraction that should be
774 * awarded for this resonse.
775 * @param array $response a response.
776 * @return question_answer the matching answer.
777 */
778 public function get_matching_answer(array $response) {
779 return $this->gradingstrategy->grade($response);
780 }
781
782 /**
783 * @return question_answer an answer that contains the a response that would
784 * get full marks.
785 */
786 public function get_correct_answer() {
787 return $this->gradingstrategy->get_correct_answer();
788 }
789
790 public function grade_response(array $response) {
791 $answer = $this->get_matching_answer($response);
792 if ($answer) {
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793 return array($answer->fraction,
794 question_state::graded_state_for_fraction($answer->fraction));
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795 } else {
796 return array(0, question_state::$gradedwrong);
797 }
798 }
799
800 public function classify_response(array $response) {
801 if (empty($response['answer'])) {
802 return array($this->id => question_classified_response::no_response());
803 }
804
805 $ans = $this->get_matching_answer($response);
806 if (!$ans) {
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807 return array($this->id => new question_classified_response(
808 0, $response['answer'], 0));
d1b7e03d 809 }
24400682 810
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811 return array($this->id => new question_classified_response(
812 $ans->id, $response['answer'], $ans->fraction));
813 }
814}
815
816
817/**
818 * Class to represent a question answer, loaded from the question_answers table
819 * in the database.
820 *
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821 * @copyright 2009 The Open University
822 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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823 */
824class question_answer {
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825 /** @var integer the answer id. */
826 public $id;
827
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828 /** @var string the answer. */
829 public $answer;
830
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831 /** @var integer one of the FORMAT_... constans. */
832 public $answerformat = FORMAT_PLAIN;
833
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834 /** @var number the fraction this answer is worth. */
835 public $fraction;
836
837 /** @var string the feedback for this answer. */
838 public $feedback;
839
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840 /** @var integer one of the FORMAT_... constans. */
841 public $feedbackformat;
842
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843 /**
844 * Constructor.
22cebed5 845 * @param int $id the answer.
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846 * @param string $answer the answer.
847 * @param number $fraction the fraction this answer is worth.
848 * @param string $feedback the feedback for this answer.
22cebed5 849 * @param int $feedbackformat the format of the feedback.
d1b7e03d 850 */
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851 public function __construct($id, $answer, $fraction, $feedback, $feedbackformat) {
852 $this->id = $id;
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853 $this->answer = $answer;
854 $this->fraction = $fraction;
855 $this->feedback = $feedback;
5f7cfba7 856 $this->feedbackformat = $feedbackformat;
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857 }
858}
859
860
861/**
862 * Class to represent a hint associated with a question.
863 * Used by iteractive mode, etc. A question has an array of these.
864 *
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865 * @copyright 2010 The Open University
866 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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867 */
868class question_hint {
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869 /** @var integer The hint id. */
870 public $id;
871 /** @var string The feedback hint to be shown. */
d1b7e03d 872 public $hint;
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873 /** @var integer The corresponding text FORMAT_... type. */
874 public $hintformat;
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875
876 /**
877 * Constructor.
f7970e3c 878 * @param int the hint id from the database.
d1b7e03d 879 * @param string $hint The hint text
f7970e3c 880 * @param int the corresponding text FORMAT_... type.
d1b7e03d 881 */
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882 public function __construct($id, $hint, $hintformat) {
883 $this->id = $id;
d1b7e03d 884 $this->hint = $hint;
7a719748 885 $this->hintformat = $hintformat;
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886 }
887
888 /**
889 * Create a basic hint from a row loaded from the question_hints table in the database.
890 * @param object $row with $row->hint set.
891 * @return question_hint
892 */
893 public static function load_from_record($row) {
7a719748 894 return new question_hint($row->id, $row->hint, $row->hintformat);
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895 }
896
897 /**
898 * Adjust this display options according to the hint settings.
899 * @param question_display_options $options
900 */
901 public function adjust_display_options(question_display_options $options) {
902 // Do nothing.
903 }
904}
905
906
907/**
908 * An extension of {@link question_hint} for questions like match and multiple
909 * choice with multile answers, where there are options for whether to show the
910 * number of parts right at each stage, and to reset the wrong parts.
911 *
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912 * @copyright 2010 The Open University
913 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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914 */
915class question_hint_with_parts extends question_hint {
916 /** @var boolean option to show the number of sub-parts of the question that were right. */
917 public $shownumcorrect;
918
919 /** @var boolean option to clear the parts of the question that were wrong on retry. */
920 public $clearwrong;
921
922 /**
923 * Constructor.
f7970e3c 924 * @param int the hint id from the database.
d1b7e03d 925 * @param string $hint The hint text
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926 * @param int the corresponding text FORMAT_... type.
927 * @param bool $shownumcorrect whether the number of right parts should be shown
928 * @param bool $clearwrong whether the wrong parts should be reset.
d1b7e03d 929 */
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930 public function __construct($id, $hint, $hintformat, $shownumcorrect, $clearwrong) {
931 parent::__construct($id, $hint, $hintformat);
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932 $this->shownumcorrect = $shownumcorrect;
933 $this->clearwrong = $clearwrong;
934 }
935
936 /**
937 * Create a basic hint from a row loaded from the question_hints table in the database.
938 * @param object $row with $row->hint, ->shownumcorrect and ->clearwrong set.
939 * @return question_hint_with_parts
940 */
941 public static function load_from_record($row) {
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942 return new question_hint_with_parts($row->id, $row->hint, $row->hintformat,
943 $row->shownumcorrect, $row->clearwrong);
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944 }
945
946 public function adjust_display_options(question_display_options $options) {
947 parent::adjust_display_options($options);
948 if ($this->clearwrong) {
949 $options->clearwrong = true;
950 }
951 $options->numpartscorrect = $this->shownumcorrect;
952 }
953}
954
955
956/**
957 * This question_grading_strategy interface. Used to share grading code between
958 * questions that that subclass {@link question_graded_by_strategy}.
959 *
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960 * @copyright 2009 The Open University
961 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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962 */
963interface question_grading_strategy {
964 /**
965 * Return a question answer that describes the outcome (fraction and feeback)
966 * for a particular respons.
967 * @param array $response the response.
968 * @return question_answer the answer describing the outcome.
969 */
970 public function grade(array $response);
971
972 /**
973 * @return question_answer an answer that contains the a response that would
974 * get full marks.
975 */
976 public function get_correct_answer();
977}
978
979
980/**
981 * This interface defines the methods that a {@link question_definition} must
982 * implement if it is to be graded by the
983 * {@link question_first_matching_answer_grading_strategy}.
984 *
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985 * @copyright 2009 The Open University
986 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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987 */
988interface question_response_answer_comparer {
989 /** @return array of {@link question_answers}. */
990 public function get_answers();
991
992 /**
993 * @param array $response the response.
994 * @param question_answer $answer an answer.
f7970e3c 995 * @return bool whether the response matches the answer.
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996 */
997 public function compare_response_with_answer(array $response, question_answer $answer);
998}
999
1000
1001/**
1002 * This grading strategy is used by question types like shortanswer an numerical.
1003 * It gets a list of possible answers from the question, and returns the first one
1004 * that matches the given response. It returns the first answer with fraction 1.0
1005 * when asked for the correct answer.
1006 *
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1007 * @copyright 2009 The Open University
1008 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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1009 */
1010class question_first_matching_answer_grading_strategy implements question_grading_strategy {
1011 /**
1012 * @var question_response_answer_comparer (presumably also a
1013 * {@link question_definition}) the question we are doing the grading for.
1014 */
1015 protected $question;
1016
1017 /**
1018 * @param question_response_answer_comparer $question (presumably also a
1019 * {@link question_definition}) the question we are doing the grading for.
1020 */
1021 public function __construct(question_response_answer_comparer $question) {
1022 $this->question = $question;
1023 }
1024
1025 public function grade(array $response) {
1026 foreach ($this->question->get_answers() as $aid => $answer) {
1027 if ($this->question->compare_response_with_answer($response, $answer)) {
1028 $answer->id = $aid;
1029 return $answer;
1030 }
1031 }
1032 return null;
1033 }
1034
1035 public function get_correct_answer() {
1036 foreach ($this->question->get_answers() as $answer) {
1037 $state = question_state::graded_state_for_fraction($answer->fraction);
1038 if ($state == question_state::$gradedright) {
1039 return $answer;
1040 }
1041 }
1042 return null;
1043 }
01c898ec 1044}