今天继续了解model类
1 /**
2 * Returns the form name that this model class should use.
3 *
4 * 返回表单的名称，就是这个 model 的类名
5 *
6 * The form name is mainly used by [[\yii\widgets\ActiveForm]] to determine how to name
7 * the input fields for the attributes in a model. If the form name is "A" and an attribute
8 * name is "b", then the corresponding input name would be "A[b]". If the form name is
9 * an empty string, then the input name would be "b".
10 *
11 * By default, this method returns the model class name (without the namespace part)
12 * as the form name. You may override it when the model is used in different forms.
13 *
14 * @return string the form name of this model class.
15 */
16 public function formName()
17 {
18 // ReflectionClass 类包含了一个类的有关信息
19 $reflector = new ReflectionClass($this);
20 // 获取类的短名，就是不含命名空间（namespace）的那一部分
21 return $reflector->getShortName();
22 }
23
24 /**
25 * Returns the list of attribute names.
26 * 返回属性名的列表，注意：只会返回 public 且不是 static 的属性
27 * By default, this method returns all public non-static properties of the class.
28 * You may override this method to change the default behavior.
29 * @return array list of attribute names.
30 */
31 public function attributes()
32 {
33 $class = new ReflectionClass($this);
34 $names = [];
35 // ReflectionClass::getProperties — 获取一组属性
36 // ReflectionProperty::IS_STATIC 指示了 static 的属性。
37 // ReflectionProperty::IS_PUBLIC 指示了 public 的属性。
38 // ReflectionProperty::IS_PROTECTED 指示了 protected 的属性。
39 // ReflectionProperty::IS_PRIVATE 指示了 private 的属性。
40 foreach ($class->getProperties(\ReflectionProperty::IS_PUBLIC) as $property) {
41 // 如果是public的属性，并且不是static的，就认为是它的attribute
42 if (!$property->isStatic()) {
43 // 获取该属性的名称
44 $names[] = $property->getName();
45 }
46 }
47
48 return $names;
49 }
50
51 /**
52 * Returns the attribute labels.
53 * 返回属性的标签
54 *
55 * Attribute labels are mainly used for display purpose. For example, given an attribute
56 * `firstName`, we can declare a label `First Name` which is more user-friendly and can
57 * be displayed to end users.
58 *
59 * By default an attribute label is generated using [[generateAttributeLabel()]].
60 * This method allows you to explicitly specify attribute labels.
61 *
62 * Note, in order to inherit labels defined in the parent class, a child class needs to
63 * merge the parent labels with child labels using functions such as `array_merge()`.
64 *
65 * @return array attribute labels (name => label)
66 * @see generateAttributeLabel()
67 */
68 public function attributeLabels()
69 {
70 return [];
71 }
72
73 /**
74 * Performs the data validation.
75 *
76 * This method executes the validation rules applicable to the current [[scenario]].
77 * The following criteria are used to determine whether a rule is currently applicable:
78 *
79 * - the rule must be associated with the attributes relevant to the current scenario;
80 * - the rules must be effective for the current scenario.
81 *
82 * This method will call [[beforeValidate()]] and [[afterValidate()]] before and
83 * after the actual validation, respectively. If [[beforeValidate()]] returns false,
84 * the validation will be cancelled and [[afterValidate()]] will not be called.
85 *
86 * Errors found during the validation can be retrieved via [[getErrors()]],
87 * [[getFirstErrors()]] and [[getFirstError()]].
88 *
89 * @param array $attributeNames list of attribute names that should be validated.
90 * If this parameter is empty, it means any attribute listed in the applicable
91 * validation rules should be validated.
92 * @param boolean $clearErrors whether to call [[clearErrors()]] before performing validation
93 * @return boolean whether the validation is successful without any error.
94 * @throws InvalidParamException if the current scenario is unknown.
95 */
96 public function validate($attributeNames = null, $clearErrors = true)
97 {
98 if ($clearErrors) {
99 $this->clearErrors();
100 }
101
102 if (!$this->beforeValidate()) {
103 return false;
104 }
105
106 $scenarios = $this->scenarios();
107 $scenario = $this->getScenario();
108 if (!isset($scenarios[$scenario])) {
109 throw new InvalidParamException("Unknown scenario: $scenario");
110 }
111
112 if ($attributeNames === null) {
113 $attributeNames = $this->activeAttributes();
114 }
115
116 foreach ($this->getActiveValidators() as $validator) {
117 $validator->validateAttributes($this, $attributeNames);
118 }
119 $this->afterValidate();
120
121 return !$this->hasErrors();
122 }
123
124 /**
125 * This method is invoked before validation starts.
126 * The default implementation raises a `beforeValidate` event.
127 * You may override this method to do preliminary checks before validation.
128 * Make sure the parent implementation is invoked so that the event can be raised.
129 * @return boolean whether the validation should be executed. Defaults to true.
130 * If false is returned, the validation will stop and the model is considered invalid.
131 */
132 public function beforeValidate()
133 {
134 $event = new ModelEvent;
135 $this->trigger(self::EVENT_BEFORE_VALIDATE, $event);
136
137 return $event->isValid;
138 }
139
140 /**
141 * This method is invoked after validation ends.
142 * The default implementation raises an `afterValidate` event.
143 * You may override this method to do postprocessing after validation.
144 * Make sure the parent implementation is invoked so that the event can be raised.
145 */
146 public function afterValidate()
147 {
148 $this->trigger(self::EVENT_AFTER_VALIDATE);
149 }
150
151 /**
152 * Returns all the validators declared in [[rules()]].
153 *
154 * This method differs from [[getActiveValidators()]] in that the latter
155 * only returns the validators applicable to the current [[scenario]].
156 *
157 * Because this method returns an ArrayObject object, you may
158 * manipulate it by inserting or removing validators (useful in model behaviors).
159 * For example,
160 *
161 * ~~~
162 * $model->validators[] = $newValidator;
163 * ~~~
164 *
165 * @return ArrayObject|\yii\validators\Validator[] all the validators declared in the model.
166 */
167 public function getValidators()
168 {
169 if ($this->_validators === null) {
170 $this->_validators = $this->createValidators();
171 }
172 return $this->_validators;
173 }
174
175 /**
176 * Returns the validators applicable to the current [[scenario]].
177 * @param string $attribute the name of the attribute whose applicable validators should be returned.
178 * If this is null, the validators for ALL attributes in the model will be returned.
179 * @return \yii\validators\Validator[] the validators applicable to the current [[scenario]].
180 */
181 public function getActiveValidators($attribute = null)
182 {
183 $validators = [];
184 $scenario = $this->getScenario();
185 foreach ($this->getValidators() as $validator) {
186 if ($validator->isActive($scenario) && ($attribute === null || in_array($attribute, $validator->attributes, true))) {
187 $validators[] = $validator;
188 }
189 }
190 return $validators;
191 }
192
193 /**
194 * Creates validator objects based on the validation rules specified in [[rules()]].
195 * Unlike [[getValidators()]], each time this method is called, a new list of validators will be returned.
196 * @return ArrayObject validators
197 * @throws InvalidConfigException if any validation rule configuration is invalid
198 */
199 public function createValidators()
200 {
201 $validators = new ArrayObject;
202 foreach ($this->rules() as $rule) {
203 if ($rule instanceof Validator) {
204 $validators->append($rule);
205 } elseif (is_array($rule) && isset($rule[0], $rule[1])) { // attributes, validator type
206 $validator = Validator::createValidator($rule[1], $this, (array) $rule[0], array_slice($rule, 2));
207 $validators->append($validator);
208 } else {
209 throw new InvalidConfigException('Invalid validation rule: a rule must specify both attribute names and validator type.');
210 }
211 }
212 return $validators;
213 }
214
215 /**
216 * Returns a value indicating whether the attribute is required.
217 * This is determined by checking if the attribute is associated with a
218 * [[\yii\validators\RequiredValidator|required]] validation rule in the
219 * current [[scenario]].
220 *
221 * Note that when the validator has a conditional validation applied using
222 * [[\yii\validators\RequiredValidator::$when|$when]] this method will return
223 * `false` regardless of the `when` condition because it may be called be
224 * before the model is loaded with data.
225 *
226 * @param string $attribute attribute name
227 * @return boolean whether the attribute is required
228 */
229 public function isAttributeRequired($attribute)
230 {
231 foreach ($this->getActiveValidators($attribute) as $validator) {
232 if ($validator instanceof RequiredValidator && $validator->when === null) {
233 return true;
234 }
235 }
236 return false;
237 }
238
239 /**
240 * Returns a value indicating whether the attribute is safe for massive assignments.
241 * @param string $attribute attribute name
242 * @return boolean whether the attribute is safe for massive assignments
243 * @see safeAttributes()
244 */
245 public function isAttributeSafe($attribute)
246 {
247 return in_array($attribute, $this->safeAttributes(), true);
248 }
249
250 /**
251 * Returns a value indicating whether the attribute is active in the current scenario.
252 * @param string $attribute attribute name
253 * @return boolean whether the attribute is active in the current scenario
254 * @see activeAttributes()
255 */
256 public function isAttributeActive($attribute)
257 {
258 return in_array($attribute, $this->activeAttributes(), true);
259 }
260
261 /**
262 * Returns the text label for the specified attribute.
263 * @param string $attribute the attribute name
264 * @return string the attribute label
265 * @see generateAttributeLabel()
266 * @see attributeLabels()
267 */
268 public function getAttributeLabel($attribute)
269 {
270 $labels = $this->attributeLabels();
271 return isset($labels[$attribute]) ? $labels[$attribute] : $this->generateAttributeLabel($attribute);
272 }
273
274 /**
275 * Returns a value indicating whether there is any validation error.
276 * @param string|null $attribute attribute name. Use null to check all attributes.
277 * @return boolean whether there is any error.
278 */
279 public function hasErrors($attribute = null)
280 {
281 return $attribute === null ? !empty($this->_errors) : isset($this->_errors[$attribute]);
282 }
283
284 /**
285 * Returns the errors for all attribute or a single attribute.
286 * @param string $attribute attribute name. Use null to retrieve errors for all attributes.
287 * @property array An array of errors for all attributes. Empty array is returned if no error.
288 * The result is a two-dimensional array. See [[getErrors()]] for detailed description.
289 * @return array errors for all attributes or the specified attribute. Empty array is returned if no error.
290 * Note that when returning errors for all attributes, the result is a two-dimensional array, like the following:
291 *
292 * ~~~
293 * [
294 * 'username' => [
295 * 'Username is required.',
296 * 'Username must contain only word characters.',
297 * ],
298 * 'email' => [
299 * 'Email address is invalid.',
300 * ]
301 * ]
302 * ~~~
303 *
304 * @see getFirstErrors()
305 * @see getFirstError()
306 */
307 public function getErrors($attribute = null)
308 {
309 if ($attribute === null) {
310 return $this->_errors === null ? [] : $this->_errors;
311 } else {
312 return isset($this->_errors[$attribute]) ? $this->_errors[$attribute] : [];
313 }
314 }
315
316 /**
317 * Returns the first error of every attribute in the model.
318 * @return array the first errors. The array keys are the attribute names, and the array
319 * values are the corresponding error messages. An empty array will be returned if there is no error.
320 * @see getErrors()
321 * @see getFirstError()
322 */
323 public function getFirstErrors()
324 {
325 if (empty($this->_errors)) {
326 return [];
327 } else {
328 $errors = [];
329 foreach ($this->_errors as $name => $es) {
330 if (!empty($es)) {
331 $errors[$name] = reset($es);
332 }
333 }
334
335 return $errors;
336 }
337 }
338
339 /**
340 * Returns the first error of the specified attribute.
341 * @param string $attribute attribute name.
342 * @return string the error message. Null is returned if no error.
343 * @see getErrors()
344 * @see getFirstErrors()
345 */
346 public function getFirstError($attribute)
347 {
348 return isset($this->_errors[$attribute]) ? reset($this->_errors[$attribute]) : null;
349 }
350
351 /**
352 * Adds a new error to the specified attribute.
353 * @param string $attribute attribute name
354 * @param string $error new error message
355 */
356 public function addError($attribute, $error = '')
357 {
358 $this->_errors[$attribute][] = $error;
359 }
360
361 /**
362 * Adds a list of errors.
363 * @param array $items a list of errors. The array keys must be attribute names.
364 * The array values should be error messages. If an attribute has multiple errors,
365 * these errors must be given in terms of an array.
366 * You may use the result of [[getErrors()]] as the value for this parameter.
367 * @since 2.0.2
368 */
369 public function addErrors(array $items)
370 {
371 foreach ($items as $attribute => $errors) {
372 if (is_array($errors)) {
373 foreach ($errors as $error) {
374 $this->addError($attribute, $error);
375 }
376 } else {
377 $this->addError($attribute, $errors);
378 }
379 }
380 }
381
382 /**
383 * Removes errors for all attributes or a single attribute.
384 * @param string $attribute attribute name. Use null to remove errors for all attribute.
385 */
386 public function clearErrors($attribute = null)
387 {
388 if ($attribute === null) {
389 $this->_errors = [];
390 } else {
391 unset($this->_errors[$attribute]);
392 }
393 }
394
395 /**
396 * Generates a user friendly attribute label based on the give attribute name.
397 * This is done by replacing underscores, dashes and dots with blanks and
398 * changing the first letter of each word to upper case.
399 * For example, 'department_name' or 'DepartmentName' will generate 'Department Name'.
400 * @param string $name the column name
401 * @return string the attribute label
402 */
403 public function generateAttributeLabel($name)
404 {
405 return Inflector::camel2words($name, true);
406 }
407
408 /**
409 * Returns attribute values.
410 * @param array $names list of attributes whose value needs to be returned.
411 * Defaults to null, meaning all attributes listed in [[attributes()]] will be returned.
412 * If it is an array, only the attributes in the array will be returned.
413 * @param array $except list of attributes whose value should NOT be returned.
414 * @return array attribute values (name => value).
415 */
416 public function getAttributes($names = null, $except = [])
417 {
418 $values = [];
419 if ($names === null) {
420 $names = $this->attributes();
421 }
422 foreach ($names as $name) {
423 $values[$name] = $this->$name;
424 }
425 foreach ($except as $name) {
426 unset($values[$name]);
427 }
428
429 return $values;
430 }
431
432 /**
433 * Sets the attribute values in a massive way.
434 * @param array $values attribute values (name => value) to be assigned to the model.
435 * @param boolean $safeOnly whether the assignments should only be done to the safe attributes.
436 * A safe attribute is one that is associated with a validation rule in the current [[scenario]].
437 * @see safeAttributes()
438 * @see attributes()
439 */
440 public function setAttributes($values, $safeOnly = true)
441 {
442 // 必须是个数组
443 if (is_array($values)) {
444 // array_flip — 交换数组中的键和值
445 // 将属性放到了 key 上
446 // 默认取 safeAttributes 中的属性
447 $attributes = array_flip($safeOnly ? $this->safeAttributes() : $this->attributes());
448 foreach ($values as $name => $value) {
449 if (isset($attributes[$name])) {
450 // 如果存在该属性，就直接赋值
451 $this->$name = $value;
452 } elseif ($safeOnly) {
453 // 如果不存在，而且是 safeOnly 的话，就触发一下 onUnsafeAttribute 方法
454 $this->onUnsafeAttribute($name, $value);
455 }
456 }
457 }
458 }
459
460 /**
461 * This method is invoked when an unsafe attribute is being massively assigned.
462 * The default implementation will log a warning message if YII_DEBUG is on.
463 * It does nothing otherwise.
464 * @param string $name the unsafe attribute name
465 * @param mixed $value the attribute value
466 */
467 public function onUnsafeAttribute($name, $value)
468 {
469 if (YII_DEBUG) {
470 // 如果是调试状态，就打 log 记录下，没有成功设置的不安全的属性
471 Yii::trace("Failed to set unsafe attribute '$name' in '" . get_class($this) . "'.", __METHOD__);
472 }
473 }
474
475 /**
476 * Returns the scenario that this model is used in.
477 *
478 * Scenario affects how validation is performed and which attributes can
479 * be massively assigned.
480 *
481 * @return string the scenario that this model is in. Defaults to [[SCENARIO_DEFAULT]].
482 */
483 public function getScenario()
484 {
485 // 获取当前的场景
486 return $this->_scenario;
487 }
488
489 /**
490 * Sets the scenario for the model.
491 * Note that this method does not check if the scenario exists or not.
492 * The method [[validate()]] will perform this check.
493 * @param string $value the scenario that this model is in.
494 */
495 public function setScenario($value)
496 {
497 // 设置当前的场景
498 $this->_scenario = $value;
499 }
500
501 /**
502 * Returns the attribute names that are safe to be massively assigned in the current scenario.
503 * @return string[] safe attribute names
504 */
505 public function safeAttributes()
506 {
507 // 获取当前的场景
508 $scenario = $this->getScenario();
509 // 获取所有场景及其属性
510 $scenarios = $this->scenarios();
511 if (!isset($scenarios[$scenario])) {
512 // 场景不存在，就返回空
513 return [];
514 }
515 $attributes = [];
516 foreach ($scenarios[$scenario] as $attribute) {
517 // 将开头不是！的属性才会放入到 safeAttributes 中, 即以！开头的属性不会被放到 safeAttributes 中
518 if ($attribute[0] !== '!') {
519 $attributes[] = $attribute;
520 }
521 }
522
523 return $attributes;
524 }
525
526 /**
527 * Returns the attribute names that are subject to validation in the current scenario.
528 * @return string[] safe attribute names
529 */
530 public function activeAttributes()
531 {
532 // 同上
533 $scenario = $this->getScenario();
534 $scenarios = $this->scenarios();
535 if (!isset($scenarios[$scenario])) {
536 return [];
537 }
538 // 获取当前场景中的所有属性
539 $attributes = $scenarios[$scenario];
540 foreach ($attributes as $i => $attribute) {
541 // 如果属性名以！开头，就把！截取掉
542 // ！开头的属性来自rules，加！能够使规则（即 validator）生效，但却能够不出现在 safeAttributes 中
543 if ($attribute[0] === '!') {
544 $attributes[$i] = substr($attribute, 1);
545 }
546 }
547
548 return $attributes;
549 }
550
551 /**
552 * Populates the model with the data from end user.
553 * The data to be loaded is `$data[formName]`, where `formName` refers to the value of [[formName()]].
554 * If [[formName()]] is empty, the whole `$data` array will be used to populate the model.
555 * The data being populated is subject to the safety check by [[setAttributes()]].
556 * 加载数据到所在的 model 中
557 * @param array $data the data array. This is usually `$_POST` or `$_GET`, but can also be any valid array
558 * supplied by end user.
559 * @param string $formName the form name to be used for loading the data into the model.
560 * If not set, [[formName()]] will be used.
561 * @return boolean whether the model is successfully populated with some data.
562 */
563 public function load($data, $formName = null)
564 {
565 // 如果存在 yii 的 form，就使用该 form，否则就拿到所在类的名称（不含 namespace）
566 $scope = $formName === null ? $this->formName() : $formName;
567 if ($scope === '' && !empty($data)) {
568 // 如果 $scope 为空字符串，且 $data不为空，就设置属性
569 // 即 $formName 为空字符串，且 $data不为空
570 $this->setAttributes($data);
571
572 return true;
573 } elseif (isset($data[$scope])) {
574 // 否则，必须存在 $data[$scope]，使用 $data[$scope] 去设置属性
575 $this->setAttributes($data[$scope]);
576
577 return true;
578 } else {
579 return false;
580 }
581 }
582
583 /**
584 * Populates a set of models with the data from end user.
585 * 加载数据到所在的 model 的集合中
586 * This method is mainly used to collect tabular data input.
587 * The data to be loaded for each model is `$data[formName][index]`, where `formName`
588 * refers to the value of [[formName()]], and `index` the index of the model in the `$models` array.
589 * If [[formName()]] is empty, `$data[index]` will be used to populate each model.
590 * The data being populated to each model is subject to the safety check by [[setAttributes()]].
591 * @param array $models the models to be populated. Note that all models should have the same class.
592 * @param array $data the data array. This is usually `$_POST` or `$_GET`, but can also be any valid array
593 * supplied by end user.
594 * @param string $formName the form name to be used for loading the data into the models.
595 * If not set, it will use the [[formName()]] value of the first model in `$models`.
596 * This parameter is available since version 2.0.1.
597 * @return boolean whether at least one of the models is successfully populated.
598 */
599 public static function loadMultiple($models, $data, $formName = null)
600 {
601 if ($formName === null) {
602 /* @var $first Model */
603 // reset — 将数组的内部指针指向第一个单元
604 $first = reset($models);
605 if ($first === false) {
606 // 不存在就返回 false
607 return false;
608 }
609 // 拿到所在类的名称（不含 namespace）
610 $formName = $first->formName();
611 }
612
613 $success = false;
614 // 遍历 $models，一个个 load 数据
615 foreach ($models as $i => $model) {
616 /* @var $model Model */
617 if ($formName == '') {
618 if (!empty($data[$i])) {
619 // 数据不为空，就 load 到相应的 model 中
620 $model->load($data[$i], '');
621 $success = true;
622 }
623 } elseif (!empty($data[$formName][$i])) {
624 // 存在 $formName，且数据不为空，就 load 到相应的 model 中
625 $model->load($data[$formName][$i], '');
626 $success = true;
627 }
628 }
629
630 return $success;
631 }
632
633 /**
634 * Validates multiple models.
635 * This method will validate every model. The models being validated may
636 * be of the same or different types.
637 * @param array $models the models to be validated
638 * @param array $attributeNames list of attribute names that should be validated.
639 * If this parameter is empty, it means any attribute listed in the applicable
640 * validation rules should be validated.
641 * @return boolean whether all models are valid. False will be returned if one
642 * or multiple models have validation error.
643 */
644 public static function validateMultiple($models, $attributeNames = null)
645 {
646 $valid = true;
647 /* @var $model Model */
648 foreach ($models as $model) {
649 //遍历$models 调用validate（）方法
650 $valid = $model->validate($attributeNames) && $valid;
651 }
652
653 return $valid;
654 }
655
656 /**
657 * Returns the list of fields that should be returned by default by [[toArray()]] when no specific fields are specified.
658 * 以数组形式返回定义的一个字段名或字段
659 * A field is a named element in the returned array by [[toArray()]].
660 *
661 * This method should return an array of field names or field definitions.
662 * 此方法应该返回一个字段名或字段定义的数组
663 * If the former, the field name will be treated as an object property name whose value will be used
664 * as the field value. If the latter, the array key should be the field name while the array value should be
665 * the corresponding field definition which can be either an object property name or a PHP callable
666 * returning the corresponding field value. The signature of the callable should be:
667 * 如果前者，该字段名将被视为一个对象属性名，其值将用作该字段值。
668 * 如果是后者，数组的键应该是字段名称，数组的值应相应的字段定义可以是一个对象的属性名称或PHP回调函数
669 * ```php
670 * function ($field, $model) {
671 * // return field value
672 * }
673 * ```
674 *
675 * For example, the following code declares four fields:
676 *
677 * - `email`: the field name is the same as the property name `email`;
678 * - `firstName` and `lastName`: the field names are `firstName` and `lastName`, and their
679 * values are obtained from the `first_name` and `last_name` properties;
680 * - `fullName`: the field name is `fullName`. Its value is obtained by concatenating `first_name`
681 * and `last_name`.
682 *
683 * ```php
684 * return [
685 * 'email',
686 * 'firstName' => 'first_name',
687 * 'lastName' => 'last_name',
688 * 'fullName' => function ($model) {
689 * return $model->first_name . ' ' . $model->last_name;
690 * },
691 * ];
692 * ```
693 *
694 * In this method, you may also want to return different lists of fields based on some context
695 * information. For example, depending on [[scenario]] or the privilege of the current application user,
696 * you may return different sets of visible fields or filter out some fields.
697 * 在这个方法中，可能还希望在根据条件返回不同的字段列表，例如，根据[[scenario]]或者当前应用程序用户的权限
698 * 设置不同的可见字段或者过滤某些字段
699 * The default implementation of this method returns [[attributes()]] indexed by the same attribute names.
700 * 默认返回[[attributes()]]中的属性名为索引的所有字段
701 * @return array the list of field names or field definitions.
702 * @see toArray()
703 */
704 public function fields()
705 {
706 $fields = $this->attributes();
707 // array_combine — 创建一个数组，用一个数组的值作为其键名，另一个数组的值作为其值
708 return array_combine($fields, $fields);
709 }
710
711 /**
712 * Returns an iterator for traversing the attributes in the model.
713 * This method is required by the interface IteratorAggregate.
714 * @return ArrayIterator an iterator for traversing the items in the list.
715 */
716 public function getIterator()
717 {
718 // 获取该 model 的所有属性
719 $attributes = $this->getAttributes();
720 // ArrayIterator 这个迭代器允许在遍历数组和对象时删除和更新值与键
721 // 当你想多次遍历相同数组时你需要实例化 ArrayObject，然后让这个实例创建一个 ArrayIteratror 实例, 然后使用 foreach 或者 手动调用 getIterator() 方法
722 return new ArrayIterator($attributes);
723 }
724
725 /**
726 * Returns whether there is an element at the specified offset.
727 * This method is required by the SPL interface `ArrayAccess`.
728 * It is implicitly called when you use something like `isset($model[$offset])`.
729 * @param mixed $offset the offset to check on
730 * @return boolean
731 */
732 public function offsetExists($offset)
733 {
734 // 将 isset($model[$offset]) 重写为 isset($model->$offset)
735 return $this->$offset !== null;
736 }
737
738 /**
739 * Returns the element at the specified offset.
740 * This method is required by the SPL interface `ArrayAccess`.
741 * It is implicitly called when you use something like `$value = $model[$offset];`.
742 * @param mixed $offset the offset to retrieve element.
743 * @return mixed the element at the offset, null if no element is found at the offset
744 */
745 public function offsetGet($offset)
746 {
747 // 将获取 $model[$offset] 重写为 $model->$offset
748 return $this->$offset;
749 }
750
751 /**
752 * Sets the element at the specified offset.
753 * This method is required by the SPL interface `ArrayAccess`.
754 * It is implicitly called when you use something like `$model[$offset] = $item;`.
755 * @param integer $offset the offset to set element
756 * @param mixed $item the element value
757 */
758 public function offsetSet($offset, $item)
759 {
760 // 将 $model[$offset] = $item 重写为 $model->$offset = $item
761 $this->$offset = $item;
762 }
763
764 /**
765 * Sets the element value at the specified offset to null.
766 * This method is required by the SPL interface `ArrayAccess`.
767 * It is implicitly called when you use something like `unset($model[$offset])`.
768 * @param mixed $offset the offset to unset element
769 */
770 public function offsetUnset($offset)
771 {
772 // 将 unset($model[$offset]) 重写为 $model->$offset = null
773 $this->$offset = null;
774 }