Как установить _models и _keys для BaseDataProvider

<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/

namespace yii\data;

use Yii;
use yii\base\Component;
use yii\base\InvalidParamException;

/**
* BaseDataProvider provides a base class that implements the [[DataProviderInterface]].
*
* @property integer $count The number of data models in the current page. This property is read-only.
* @property array $keys The list of key values corresponding to [[models]]. Each data model in [[models]] is
* uniquely identified by the corresponding key value in this array.
* @property array $models The list of data models in the current page.
* @property Pagination|boolean $pagination The pagination object. If this is false, it means the pagination
* is disabled. Note that the type of this property differs in getter and setter. See [[getPagination()]] and
* [[setPagination()]] for details.
* @property Sort|boolean $sort The sorting object. If this is false, it means the sorting is disabled. Note
* that the type of this property differs in getter and setter. See [[getSort()]] and [[setSort()]] for details.
* @property integer $totalCount Total number of possible data models.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
abstract class BaseDataProvider extends Component implements DataProviderInterface
{
/**
* @var string an ID that uniquely identifies the data provider among all data providers.
* You should set this property if the same page contains two or more different data providers.
* Otherwise, the [[pagination]] and [[sort]] may not work properly.
*/
public $id;

private $_sort;
private $_pagination;
private $_keys;
private $_models;
private $_totalCount;/**
* Prepares the data models that will be made available in the current page.
* @return array the available data models
*/
abstract protected function prepareModels();

/**
* Prepares the keys associated with the currently available data models.
* @param array $models the available data models
* @return array the keys
*/
abstract protected function prepareKeys($models);

/**
* Returns a value indicating the total number of data models in this data provider.
* @return integer total number of data models in this data provider.
*/
abstract protected function prepareTotalCount();

/**
* Prepares the data models and keys.
*
* This method will prepare the data models and keys that can be retrieved via
* [[getModels()]] and [[getKeys()]].
*
* This method will be implicitly called by [[getModels()]] and [[getKeys()]] if it has not been called before.
*
* @param boolean $forcePrepare whether to force data preparation even if it has been done before.
*/
public function prepare($forcePrepare = false)
{
if ($forcePrepare || $this->_models === null) {
$this->_models = $this->prepareModels();
}
if ($forcePrepare || $this->_keys === null) {
$this->_keys = $this->prepareKeys($this->_models);
}
}

/**
* Returns the data models in the current page.
* @return array the list of data models in the current page.
*/
public function getModels()
{
$this->prepare();

return $this->_models;
}

/**
* Sets the data models in the current page.
* @param array $models the models in the current page
*/
public function setModels($models)
{
$this->_models = $models;
}

/**
* Returns the key values associated with the data models.
* @return array the list of key values corresponding to [[models]]. Each data model in [[models]]
* is uniquely identified by the corresponding key value in this array.
*/
public function getKeys()
{
$this->prepare();

return $this->_keys;
}

/**
* Sets the key values associated with the data models.
* @param array $keys the list of key values corresponding to [[models]].
*/
public function setKeys($keys)
{
$this->_keys = $keys;
}

/**
* Returns the number of data models in the current page.
* @return integer the number of data models in the current page.
*/
public function getCount()
{
return count($this->getModels());
}

/**
* Returns the total number of data models.
* When [[pagination]] is false, this returns the same value as [[count]].
* Otherwise, it will call [[prepareTotalCount()]] to get the count.
* @return integer total number of possible data models.
*/
public function getTotalCount()
{
if ($this->getPagination() === false) {
return $this->getCount();
} elseif ($this->_totalCount === null) {
$this->_totalCount = $this->prepareTotalCount();
}

return $this->_totalCount;
}

/**
* Sets the total number of data models.
* @param integer $value the total number of data models.
*/
public function setTotalCount($value)
{
$this->_totalCount = $value;
}

/**
* Returns the pagination object used by this data provider.
* Note that you should call [[prepare()]] or [[getModels()]] first to get correct values
* of [[Pagination::totalCount]] and [[Pagination::pageCount]].
* @return Pagination|boolean the pagination object. If this is false, it means the pagination is disabled.
*/
public function getPagination()
{
if ($this->_pagination === null) {
$this->setPagination([]);
}

return $this->_pagination;
}

/**
* Sets the pagination for this data provider.
* @param array|Pagination|boolean $value the pagination to be used by this data provider.
* This can be one of the following:
*
* - a configuration array for creating the pagination object. The "class" element defaults
*   to 'yii\data\Pagination'
* - an instance of [[Pagination]] or its subclass
* - false, if pagination needs to be disabled.
*
* @throws InvalidParamException
*/
public function setPagination($value)
{
if (is_array($value)) {
$config = ['class' => Pagination::className()];
if ($this->id !== null) {
$config['pageParam'] = $this->id . '-page';
$config['pageSizeParam'] = $this->id . '-per-page';
}
$this->_pagination = Yii::createObject(array_merge($config, $value));
} elseif ($value instanceof Pagination || $value === false) {
$this->_pagination = $value;
} else {
throw new InvalidParamException('Only Pagination instance, configuration array or false is allowed.');
}
}

/**
* Returns the sorting object used by this data provider.
* @return Sort|boolean the sorting object. If this is false, it means the sorting is disabled.
*/
public function getSort()
{
if ($this->_sort === null) {
$this->setSort([]);
}

return $this->_sort;
}

/**
* Sets the sort definition for this data provider.
* @param array|Sort|boolean $value the sort definition to be used by this data provider.
* This can be one of the following:
*
* - a configuration array for creating the sort definition object. The "class" element defaults
*   to 'yii\data\Sort'
* - an instance of [[Sort]] or its subclass
* - false, if sorting needs to be disabled.
*
* @throws InvalidParamException
*/
public function setSort($value)
{
if (is_array($value)) {
$config = ['class' => Sort::className()];
if ($this->id !== null) {
$config['sortParam'] = $this->id . '-sort';
}
$this->_sort = Yii::createObject(array_merge($config, $value));
} elseif ($value instanceof Sort || $value === false) {
$this->_sort = $value;
} else {
throw new InvalidParamException('Only Sort instance, configuration array or false is allowed.');
}
}

/**
* Refreshes the data provider.
* After calling this method, if [[getModels()]], [[getKeys()]] or [[getTotalCount()]] is called again,
* they will re-execute the query and return the latest data available.
*/
public function refresh()
{
$this->_totalCount = null;
$this->_models = null;
$this->_keys = null;
}
}

Код выше является BaseDataProvider для yii2. У меня вопрос, как я могу установить _models и _keys в yii2? Какой файл мне нужно изменить, чтобы ссылка на него? Извините, я совсем новичок в yii. Пожалуйста, приведите пример, если возможно, спасибо.