Added DataProvider and IDataProvider.

framework/yii/data/DataProvider.php

+<?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;
+
+/**
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @since 2.0
+ */
+abstract class DataProvider extends Component implements IDataProvider
+{
+	private $_sort;
+	private $_pagination;
+
+	/**
+	 * @return Pagination the pagination object. If this is false, it means the pagination is disabled.
+	 */
+	public function getPagination()
+	{
+		if ($this->_pagination === null) {
+			$this->_pagination = new Pagination;
+		}
+		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)) {
+			$this->_pagination = Yii::createObject(array_merge(array('class' => 'yii\data\Pagination'), $value));
+		} elseif ($value instanceof Pagination || $value === false) {
+			$this->_pagination = $value;
+		} else {
+			throw new InvalidParamException('Only Pagination instance, configuration array or false is allowed.');
+		}
+	}
+
+	/**
+	 * @return Sort the sorting object. If this is false, it means the sorting is disabled.
+	 */
+	public function getSort()
+	{
+		if ($this->_sort === null) {
+			$this->_sort = new Sort;
+		}
+		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)) {
+			$this->_sort = Yii::createObject(array_merge(array('class' => 'yii\data\Sort'), $value));
+		} elseif ($value instanceof Sort || $value === false) {
+			$this->_sort = $value;
+		} else {
+			throw new InvalidParamException('Only Sort instance, configuration array or false is allowed.');
+		}
+	}
+
+	/**
+	 * Returns the number of data items in the current page.
+	 * @return integer the number of data items in the current page.
+	 */
+	public function getItemCount()
+	{
+		return count($this->getItems());
+	}
+}

framework/yii/data/IDataProvider.php

+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\data;
+
+/**
+ * IDataProvider is the interface that must be implemented by data provider classes.
+ *
+ * Data providers are components that can provide data that are sorted and paginated.
+ * Data providers are often used with widgets, such as [[GridView]], [[ListView]]
+ * that display data and support sorting and pagination.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @since 2.0
+ */
+interface IDataProvider
+{
+	/**
+	 * Returns the number of data items in the current page.
+	 * This is equivalent to `count($provider->getItems())`.
+	 * When [[pagination]] is false, this is the same as [[totalItemCount]].
+	 * @return integer the number of data items in the current page.
+	 */
+	public function getItemCount();
+
+	/**
+	 * Returns the total number of data items.
+	 * When [[pagination]] is false, this is the same as [[itemCount]].
+	 * @return integer total number of possible data items.
+	 */
+	public function getTotalItemCount();
+
+	/**
+	 * Returns the data items in the current page.
+	 * @return array the list of data items in the current page.
+	 */
+	public function getItems();
+
+	/**
+	 * Returns the key values associated with the data items.
+	 * @return array the list of key values corresponding to [[items]]. Each data item in [[items]]
+	 * is uniquely identified by the corresponding key value in this array.
+	 */
+	public function getKeys();
+
+	/**
+	 * @return Sort the sorting object. If this is false, it means the sorting is disabled.
+	 */
+	public function getSort();
+
+	/**
+	 * @return Pagination the pagination object. If this is false, it means the pagination is disabled.
+	 */
+	public function getPagination();
+}

framework/yii/data/Pagination.php

@@ -104,18 +104,8 @@ class Pagination extends Object
 	/**
 	 * @var integer total number of items.
 	 */
-	public $itemCount;
+	public $itemCount = 0;
 
-	/**
-	 * Constructor.
-	 * @param integer $itemCount total number of items.
-	 * @param array $config name-value pairs that will be used to initialize the object properties
-	 */
-	public function __construct($itemCount, $config = array())
-	{
-		$this->itemCount = $itemCount;
-		parent::__construct($config);
-	}
 
 	/**
 	 * @return integer number of pages