Файл: framework/caching/dependencies/CExpressionDependency.php
Строк: 111
<?php
/**
* CExpressionDependency class file.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @link http://www.yiiframework.com/
* @copyright 2008-2013 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CExpressionDependency represents a dependency based on the result of a PHP expression.
*
* CExpressionDependency performs dependency checking based on the
* result of a PHP {@link expression}.
* The dependency is reported as unchanged if and only if the result is
* the same as the one evaluated when storing the data to cache.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @package system.caching.dependencies
* @since 1.0
*/
class CExpressionDependency extends CCacheDependency
{
/**
* @var string the PHP expression whose result is used to determine the dependency.
* The expression can also be a valid serializable PHP callback.
* It will be passed with a parameter which is the dependency object itself.
*
* The PHP expression will be evaluated using {@link evaluateExpression}.
*
* A PHP expression can be any PHP code that has a value. To learn more about what an expression is,
* please refer to the {@link http://www.php.net/manual/en/language.expressions.php php manual}.
*/
public $expression;
/**
* Constructor.
* @param string $expression the PHP expression whose result is used to determine the dependency.
*/
public function __construct($expression='true')
{
$this->expression=$expression;
}
/**
* Generates the data needed to determine if dependency has been changed.
* This method returns the result of the PHP expression.
* @return mixed the data needed to determine if dependency has been changed.
*/
protected function generateDependentData()
{
return $this->evaluateExpression($this->expression);
}
}