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Diffstat (limited to 'framework/caching/CDummyCache.php')
| -rw-r--r-- | framework/caching/CDummyCache.php | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/framework/caching/CDummyCache.php b/framework/caching/CDummyCache.php new file mode 100644 index 0000000..52bf553 --- /dev/null +++ b/framework/caching/CDummyCache.php @@ -0,0 +1,164 @@ +<?php +/** + * CDummyCache class file. + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @link http://www.yiiframework.com/ + * @copyright Copyright © 2008-2011 Yii Software LLC + * @license http://www.yiiframework.com/license/ + */ + +/** + * CDummyCache is a placeholder cache component. + * + * CDummyCache does not cache anything. It is provided so that one can always configure + * a 'cache' application component and he does not need to check if Yii::app()->cache is null or not. + * By replacing CDummyCache with some other cache component, one can quickly switch from + * non-caching mode to caching mode. + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @version $Id: CDummyCache.php 3515 2011-12-28 12:29:24Z mdomba $ + * @package system.caching + * @since 1.0 + */ +class CDummyCache extends CApplicationComponent implements ICache, ArrayAccess +{ + /** + * @var string a string prefixed to every cache key so that it is unique. Defaults to {@link CApplication::getId() application ID}. + */ + public $keyPrefix; + + /** + * Initializes the application component. + * This method overrides the parent implementation by setting default cache key prefix. + */ + public function init() + { + parent::init(); + if($this->keyPrefix===null) + $this->keyPrefix=Yii::app()->getId(); + } + + /** + * Retrieves a value from cache with a specified key. + * @param string $id a key identifying the cached value + * @return mixed the value stored in cache, false if the value is not in the cache, expired or the dependency has changed. + */ + public function get($id) + { + return false; + } + + /** + * Retrieves multiple values from cache with the specified keys. + * Some caches (such as memcache, apc) allow retrieving multiple cached values at one time, + * which may improve the performance since it reduces the communication cost. + * In case a cache doesn't support this feature natively, it will be simulated by this method. + * @param array $ids list of keys identifying the cached values + * @return array list of cached values corresponding to the specified keys. The array + * is returned in terms of (key,value) pairs. + * If a value is not cached or expired, the corresponding array value will be false. + */ + public function mget($ids) + { + $results=array(); + foreach($ids as $id) + $results[$id]=false; + return $results; + } + + /** + * Stores a value identified by a key into cache. + * If the cache already contains such a key, the existing value and + * expiration time will be replaced with the new ones. + * + * @param string $id the key identifying the value to be cached + * @param mixed $value the value to be cached + * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire. + * @param ICacheDependency $dependency dependency of the cached item. If the dependency changes, the item is labeled invalid. + * @return boolean true if the value is successfully stored into cache, false otherwise + */ + public function set($id,$value,$expire=0,$dependency=null) + { + return true; + } + + /** + * Stores a value identified by a key into cache if the cache does not contain this key. + * Nothing will be done if the cache already contains the key. + * @param string $id the key identifying the value to be cached + * @param mixed $value the value to be cached + * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire. + * @param ICacheDependency $dependency dependency of the cached item. If the dependency changes, the item is labeled invalid. + * @return boolean true if the value is successfully stored into cache, false otherwise + */ + public function add($id,$value,$expire=0,$dependency=null) + { + return true; + } + + /** + * Deletes a value with the specified key from cache + * @param string $id the key of the value to be deleted + * @return boolean if no error happens during deletion + */ + public function delete($id) + { + return true; + } + + /** + * Deletes all values from cache. + * Be careful of performing this operation if the cache is shared by multiple applications. + * @return boolean whether the flush operation was successful. + * @throws CException if this method is not overridden by child classes + */ + public function flush() + { + return true; + } + + /** + * Returns whether there is a cache entry with a specified key. + * This method is required by the interface ArrayAccess. + * @param string $id a key identifying the cached value + * @return boolean + */ + public function offsetExists($id) + { + return false; + } + + /** + * Retrieves the value from cache with a specified key. + * This method is required by the interface ArrayAccess. + * @param string $id a key identifying the cached value + * @return mixed the value stored in cache, false if the value is not in the cache or expired. + */ + public function offsetGet($id) + { + return false; + } + + /** + * Stores the value identified by a key into cache. + * If the cache already contains such a key, the existing value will be + * replaced with the new ones. To add expiration and dependencies, use the set() method. + * This method is required by the interface ArrayAccess. + * @param string $id the key identifying the value to be cached + * @param mixed $value the value to be cached + */ + public function offsetSet($id, $value) + { + } + + /** + * Deletes the value with the specified key from cache + * This method is required by the interface ArrayAccess. + * @param string $id the key of the value to be deleted + * @return boolean if no error happens during deletion + */ + public function offsetUnset($id) + { + } +} |