Finished more caching components.

framework/caching/ApcCache.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * CApcCache class file
+ * ApcCache class file
  *
  * @link http://www.yiiframework.com/
  * @copyright Copyright &copy; 2008-2012 Yii Software LLC
@@ -10,32 +10,18 @@
 namespace yii\caching;
 
 /**
- * CApcCache provides APC caching in terms of an application component.
+ * ApcCache provides APC caching in terms of an application component.
  *
- * The caching is based on {@link http://www.php.net/apc APC}.
- * To use this application component, the APC PHP extension must be loaded.
+ * To use this application component, the [APC PHP extension](http://www.php.net/apc) must be loaded.
  *
- * See {@link CCache} manual for common cache operations that are supported by CApcCache.
+ * See [[Cache]] for common cache operations that ApcCache supports.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class CApcCache extends CCache
+class ApcCache extends Cache
 {
 	/**
-	 * Initializes this application component.
-	 * This method is required by the {@link IApplicationComponent} interface.
-	 * It checks the availability of memcache.
-	 * @throws CException if APC cache extension is not loaded or is disabled.
-	 */
-	public function init()
-	{
-		parent::init();
-		if(!extension_loaded('apc'))
-			throw new CException(Yii::t('yii','CApcCache requires PHP apc extension to be loaded.'));
-	}
-
-	/**
 	 * Retrieves a value from cache with a specified key.
 	 * This is the implementation of the method declared in the parent class.
 	 * @param string $key a unique key identifying the cached value
@@ -73,7 +59,6 @@ class CApcCache extends CCache
 	/**
 	 * Stores a value identified by a key into cache if the cache does not contain this key.
 	 * This is the implementation of the method declared in the parent class.
-	 *
 	 * @param string $key the key identifying the value to be cached
 	 * @param string $value the value to be cached
 	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
@@ -99,7 +84,6 @@ class CApcCache extends CCache
 	 * Deletes all values from cache.
 	 * This is the implementation of the method declared in the parent class.
 	 * @return boolean whether the flush operation was successful.
-	 * @since 1.1.5
 	 */
 	protected function flushValues()
 	{

framework/caching/DummyCache.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * CDummyCache class file.
+ * DummyCache class file.
  *
  * @link http://www.yiiframework.com/
  * @copyright Copyright &copy; 2008-2012 Yii Software LLC
@@ -10,154 +10,74 @@
 namespace yii\caching;
 
 /**
- * CDummyCache is a placeholder cache component.
+ * DummyCache 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::$application->cache is null or not.
- * By replacing CDummyCache with some other cache component, one can quickly switch from
+ * DummyCache does not cache anything. It is provided so that one can always configure
+ * a 'cache' application component and save the check of existence of `\Yii::$application->cache`.
+ * By replacing DummyCache with some other cache component, one can quickly switch from
  * non-caching mode to caching mode.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class CDummyCache extends CApplicationComponent implements ICache, ArrayAccess
+class DummyCache extends Cache
 {
 	/**
-	 * @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)
-			$this->keyPrefix=\Yii::$application->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.
+	 * This is the implementation of the method declared in the parent class.
+	 * @param string $key a unique key identifying the cached value
+	 * @return string the value stored in cache, false if the value is not in the cache or expired.
 	 */
-	public function get($id)
+	protected function getValue($key)
 	{
 		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.
+	 * Stores a value identified by a key in cache.
+	 * This is the implementation of the method declared in the parent class.
 	 *
-	 * @param string $id the key identifying the value to be cached
-	 * @param mixed $value the value to be cached
+	 * @param string $key the key identifying the value to be cached
+	 * @param string $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,$dependency=null)
+	protected function setValue($key, $value, $expire)
 	{
 		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
+	 * This is the implementation of the method declared in the parent class.
+	 * @param string $key the key identifying the value to be cached
+	 * @param string $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,$dependency=null)
+	protected function addValue($key, $value, $expire)
 	{
 		return true;
 	}
 
 	/**
 	 * Deletes a value with the specified key from cache
-	 * @param string $id the key of the value to be deleted
+	 * This is the implementation of the method declared in the parent class.
+	 * @param string $key the key of the value to be deleted
 	 * @return boolean if no error happens during deletion
 	 */
-	public function delete($id)
+	protected function deleteValue($key)
 	{
 		return true;
 	}
 
 	/**
 	 * Deletes all values from cache.
-	 * Be careful of performing this operation if the cache is shared by multiple applications.
+	 * This is the implementation of the method declared in the parent class.
 	 * @return boolean whether the flush operation was successful.
-	 * @throws CException if this method is not overridden by child classes
 	 */
-	public function flush()
+	protected function flushValues()
 	{
 		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)
-	{
-	}
 }

framework/caching/EAcceleratorCache.php

@@ -1,108 +0,0 @@
-<?php
-/**
- * CEAcceleratorCache class file
- *
- * @link http://www.yiiframework.com/
- * @copyright Copyright &copy; 2008-2012 Yii Software LLC
- * @license http://www.yiiframework.com/license/
- */
-
-namespace yii\caching;
-
-
-/**
- * CEAcceleratorCache implements a cache application module based on {@link http://eaccelerator.net/ eaccelerator}.
- *
- * To use this application component, the eAccelerator PHP extension must be loaded.
- *
- * See {@link CCache} manual for common cache operations that are supported by CEAccelerator.
- *
- * Please note that as of v0.9.6, eAccelerator no longer supports data caching.
- * This means if you still want to use this component, your eAccelerator should be of 0.9.5.x or lower version.
- *
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @since 2.0
- */
-class CEAcceleratorCache extends CCache
-{
-	/**
-	 * Initializes this application component.
-	 * This method is required by the {@link IApplicationComponent} interface.
-	 * It checks the availability of eAccelerator.
-	 * @throws CException if eAccelerator extension is not loaded, is disabled or the cache functions are not compiled in.
-	 */
-	public function init()
-	{
-		parent::init();
-		if(!function_exists('eaccelerator_get'))
-			throw new CException(Yii::t('yii','CEAcceleratorCache requires PHP eAccelerator extension to be loaded, enabled or compiled with the "--with-eaccelerator-shared-memory" option.'));
-	}
-
-	/**
-	 * Retrieves a value from cache with a specified key.
-	 * This is the implementation of the method declared in the parent class.
-	 * @param string $key a unique key identifying the cached value
-	 * @return string the value stored in cache, false if the value is not in the cache or expired.
-	 */
-	protected function getValue($key)
-	{
-		$result = eaccelerator_get($key);
-		return $result !== NULL ? $result : false;
-	}
-
-	/**
-	 * Stores a value identified by a key in cache.
-	 * This is the implementation of the method declared in the parent class.
-	 *
-	 * @param string $key the key identifying the value to be cached
-	 * @param string $value the value to be cached
-	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
-	 * @return boolean true if the value is successfully stored into cache, false otherwise
-	 */
-	protected function setValue($key,$value,$expire)
-	{
-		return eaccelerator_put($key,$value,$expire);
-	}
-
-	/**
-	 * Stores a value identified by a key into cache if the cache does not contain this key.
-	 * This is the implementation of the method declared in the parent class.
-	 *
-	 * @param string $key the key identifying the value to be cached
-	 * @param string $value the value to be cached
-	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
-	 * @return boolean true if the value is successfully stored into cache, false otherwise
-	 */
-	protected function addValue($key,$value,$expire)
-	{
-		return (NULL === eaccelerator_get($key)) ? $this->setValue($key,$value,$expire) : false;
-	}
-
-	/**
-	 * Deletes a value with the specified key from cache
-	 * This is the implementation of the method declared in the parent class.
-	 * @param string $key the key of the value to be deleted
-	 * @return boolean if no error happens during deletion
-	 */
-	protected function deleteValue($key)
-	{
-		return eaccelerator_rm($key);
-	}
-
-	/**
-	 * Deletes all values from cache.
-	 * This is the implementation of the method declared in the parent class.
-	 * @return boolean whether the flush operation was successful.
-	 * @since 1.1.5
-	 */
-	protected function flushValues()
-	{
-		// first, remove expired content from cache
-		eaccelerator_gc();
-		// now, remove leftover cache-keys
-		$keys = eaccelerator_list_keys();
-		foreach($keys as $key)
-			$this->deleteValue(substr($key['name'], 1));
-		return true;
-	}
-}

framework/caching/MemCache.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * CMemCache class file
+ * MemCache class file
  *
  * @link http://www.yiiframework.com/
  * @copyright Copyright &copy; 2008-2012 Yii Software LLC
@@ -10,23 +10,23 @@
 namespace yii\caching;
 
 /**
- * CMemCache implements a cache application component based on {@link http://memcached.org/ memcached}.
+ * MemCache implements a cache application component based on {@link http://memcached.org/ memcached}.
  *
- * CMemCache can be configured with a list of memcache servers by settings
- * its {@link setServers servers} property. By default, CMemCache assumes
+ * MemCache can be configured with a list of memcache servers by settings
+ * its {@link setServers servers} property. By default, MemCache assumes
  * there is a memcache server running on localhost at port 11211.
  *
- * See {@link CCache} manual for common cache operations that are supported by CMemCache.
+ * See {@link CCache} manual for common cache operations that are supported by MemCache.
  *
  * Note, there is no security measure to protected data in memcache.
  * All data in memcache can be accessed by any process running in the system.
  *
- * To use CMemCache as the cache application component, configure the application as follows,
+ * To use MemCache as the cache application component, configure the application as follows,
  * <pre>
  * array(
  *     'components'=>array(
  *         'cache'=>array(
- *             'class'=>'CMemCache',
+ *             'class'=>'MemCache',
  *             'servers'=>array(
  *                 array(
  *                     'host'=>'server1',
@@ -49,21 +49,21 @@ namespace yii\caching;
  * See {@link http://www.php.net/manual/en/function.memcache-addserver.php}
  * for more details.
  *
- * CMemCache can also be used with {@link http://pecl.php.net/package/memcached memcached}.
+ * MemCache can also be used with {@link http://pecl.php.net/package/memcached memcached}.
  * To do so, set {@link useMemcached} to be true.
  *
  * @property mixed $memCache The memcache instance (or memcached if {@link useMemcached} is true) used by this component.
- * @property array $servers List of memcache server configurations. Each element is a {@link CMemCacheServerConfiguration}.
+ * @property array $servers List of memcache server configurations. Each element is a {@link MemCacheServerConfiguration}.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class CMemCache extends CCache
+class MemCache extends Cache
 {
 	/**
 	 * @var boolean whether to use memcached or memcache as the underlying caching extension.
-	 * If true {@link http://pecl.php.net/package/memcached memcached} will be used.
-	 * If false {@link http://pecl.php.net/package/memcache memcache}. will be used.
+	 * If true, [memcached](http://pecl.php.net/package/memcached) will be used.
+	 * If false, [memcache](http://pecl.php.net/package/memcache) will be used.
 	 * Defaults to false.
 	 */
 	public $useMemcached = false;
@@ -87,19 +87,18 @@ class CMemCache extends CCache
 		parent::init();
 		$servers = $this->getServers();
 		$cache = $this->getMemCache();
-		if(count($servers))
-		{
-			foreach($servers as $server)
-			{
-				if($this->useMemcached)
+		if (count($servers)) {
+			foreach ($servers as $server) {
+				if ($this->useMemcached) {
 					$cache->addServer($server->host, $server->port, $server->weight);
-				else
+				} else {
 					$cache->addServer($server->host, $server->port, $server->persistent, $server->weight, $server->timeout, $server->status);
 				}
 			}
-		else
+		} else {
 			$cache->addServer('localhost', 11211);
 		}
+	}
 
 	/**
 	 * @throws CException if extension isn't loaded
@@ -107,19 +106,19 @@ class CMemCache extends CCache
 	 */
 	public function getMemCache()
 	{
-		if($this->_cache!==null)
+		if ($this->_cache !== null) {
 			return $this->_cache;
-		else
-		{
+		} else {
 			$extension = $this->useMemcached ? 'memcached' : 'memcache';
-			if(!extension_loaded($extension))
-				throw new CException(Yii::t('yii',"CMemCache requires PHP $extension extension to be loaded."));
+			if (!extension_loaded($extension)) {
+				throw new CException(Yii::t('yii', "MemCache requires PHP $extension extension to be loaded."));
+			}
 			return $this->_cache = $this->useMemcached ? new Memcached : new Memcache;
 		}
 	}
 
 	/**
-	 * @return array list of memcache server configurations. Each element is a {@link CMemCacheServerConfiguration}.
+	 * @return array list of memcache server configurations. Each element is a {@link MemCacheServerConfiguration}.
 	 */
 	public function getServers()
 	{
@@ -133,8 +132,9 @@ class CMemCache extends CCache
 	 */
 	public function setServers($config)
 	{
-		foreach($config as $c)
-			$this->_servers[]=new CMemCacheServerConfiguration($c);
+		foreach ($config as $c) {
+			$this->_servers[] = new MemCacheServerConfiguration($c);
+		}
 	}
 
 	/**
@@ -169,10 +169,11 @@ class CMemCache extends CCache
 	 */
 	protected function setValue($key, $value, $expire)
 	{
-		if($expire>0)
+		if ($expire > 0) {
 			$expire += time();
-		else
+		} else {
 			$expire = 0;
+		}
 
 		return $this->useMemcached ? $this->_cache->set($key, $value, $expire) : $this->_cache->set($key, $value, 0, $expire);
 	}
@@ -188,10 +189,11 @@ class CMemCache extends CCache
 	 */
 	protected function addValue($key, $value, $expire)
 	{
-		if($expire>0)
+		if ($expire > 0) {
 			$expire += time();
-		else
+		} else {
 			$expire = 0;
+		}
 
 		return $this->useMemcached ? $this->_cache->add($key, $value, $expire) : $this->_cache->add($key, $value, 0, $expire);
 	}
@@ -220,7 +222,7 @@ class CMemCache extends CCache
 }
 
 /**
- * CMemCacheServerConfiguration represents the configuration data for a single memcache server.
+ * MemCacheServerConfiguration represents the configuration data for a single memcache server.
  *
  * See {@link http://www.php.net/manual/en/function.Memcache-addServer.php}
  * for detailed explanation of each configuration property.
@@ -230,7 +232,7 @@ class CMemCache extends CCache
  * @package system.caching
  * @since 1.0
  */
-class CMemCacheServerConfiguration extends CComponent
+class MemCacheServerConfiguration extends CComponent
 {
 	/**
 	 * @var string memcache server hostname or IP address
@@ -268,14 +270,15 @@ class CMemCacheServerConfiguration extends CComponent
 	 */
 	public function __construct($config)
 	{
-		if(is_array($config))
-		{
-			foreach($config as $key=>$value)
+		if (is_array($config)) {
+			foreach ($config as $key => $value) {
 				$this->$key = $value;
-			if($this->host===null)
-				throw new CException(Yii::t('yii','CMemCache server configuration must have "host" value.'));
 			}
-		else
-			throw new CException(Yii::t('yii','CMemCache server configuration must be an array.'));
+			if ($this->host === null) {
+				throw new CException(Yii::t('yii', 'MemCache server configuration must have "host" value.'));
+			}
+		} else {
+			throw new CException(Yii::t('yii', 'MemCache server configuration must be an array.'));
+		}
 	}
 }

framework/caching/WinCache.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * CWinCache class file
+ * WinCache class file
  *
  * @link http://www.yiiframework.com/
  * @copyright Copyright &copy; 2008-2012 Yii Software LLC
@@ -10,31 +10,18 @@
 namespace yii\caching;
 
 /**
- * CWinCache implements a cache application component based on {@link http://www.iis.net/expand/wincacheforphp WinCache}.
+ * WinCache provides XCache caching in terms of an application component.
  *
- * To use this application component, the WinCache PHP extension must be loaded.
+ * To use this application component, the [WinCache PHP extension](http://www.iis.net/expand/wincacheforphp)
+ * must be loaded. Also note that "wincache.ucenabled" should be set to "On" in your php.ini file.
  *
- * See {@link CCache} manual for common cache operations that are supported by CWinCache.
+ * See {@link CCache} manual for common cache operations that are supported by WinCache.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class CWinCache extends CCache {
-	/**
-	 * Initializes this application component.
-	 * This method is required by the {@link IApplicationComponent} interface.
-	 * It checks the availability of WinCache extension and WinCache user cache.
-	 * @throws CException if WinCache extension is not loaded or user cache is disabled
-	 */
-	public function init()
+class WinCache extends Cache
 {
-		parent::init();
-		if(!extension_loaded('wincache'))
-			throw new CException(Yii::t('yii', 'CWinCache requires PHP wincache extension to be loaded.'));
-		if(!ini_get('wincache.ucenabled'))
-			throw new CException(Yii::t('yii', 'CWinCache user cache is disabled. Please set wincache.ucenabled to On in your php.ini.'));
-	}
-
 	/**
 	 * Retrieves a value from cache with a specified key.
 	 * This is the implementation of the method declared in the parent class.
@@ -99,7 +86,6 @@ class CWinCache extends CCache {
 	 * Deletes all values from cache.
 	 * This is the implementation of the method declared in the parent class.
 	 * @return boolean whether the flush operation was successful.
-	 * @since 1.1.5
 	 */
 	protected function flushValues()
 	{

framework/caching/XCache.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * CXCache class file
+ * XCache class file
  *
  * @link http://www.yiiframework.com/
  * @copyright Copyright &copy; 2008-2012 Yii Software LLC
@@ -10,32 +10,20 @@
 namespace yii\caching;
 
 /**
- * CXCache implements a cache application module based on {@link http://xcache.lighttpd.net/ xcache}.
+ * XCache provides XCache caching in terms of an application component.
  *
- * To use this application component, the XCache PHP extension must be loaded.
- * Flush functionality will only work correctly if "xcache.admin.enable_auth" is set to "Off" in php.ini.
+ * To use this application component, the [XCache PHP extension](http://xcache.lighttpd.net/) must be loaded.
+ * Also note that the [[flush()]] functionality will work correctly only if "xcache.admin.enable_auth"
+ * is set to "Off" in php.ini.
  *
- * See {@link CCache} manual for common cache operations that are supported by CXCache.
+ * See [[Cache]] for common cache operations that XCache supports.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class CXCache extends CCache
+class XCache extends Cache
 {
 	/**
-	 * Initializes this application component.
-	 * This method is required by the {@link IApplicationComponent} interface.
-	 * It checks the availability of memcache.
-	 * @throws CException if memcache extension is not loaded or is disabled.
-	 */
-	public function init()
-	{
-		parent::init();
-		if(!function_exists('xcache_isset'))
-			throw new CException(Yii::t('yii','CXCache requires PHP XCache extension to be loaded.'));
-	}
-
-	/**
 	 * Retrieves a value from cache with a specified key.
 	 * This is the implementation of the method declared in the parent class.
 	 * @param string $key a unique key identifying the cached value
@@ -89,15 +77,14 @@ class CXCache extends CCache
 	 * Deletes all values from cache.
 	 * This is the implementation of the method declared in the parent class.
 	 * @return boolean whether the flush operation was successful.
-	 * @since 1.1.5
 	 */
 	protected function flushValues()
 	{
-		for($i=0, $max=xcache_count(XC_TYPE_VAR); $i<$max; $i++)
-		{
-			if(xcache_clear_cache(XC_TYPE_VAR, $i)===false)
+		for ($i = 0, $max = xcache_count(XC_TYPE_VAR); $i < $max; $i++) {
+			if (xcache_clear_cache(XC_TYPE_VAR, $i) === false) {
 				return false;
 			}
+		}
 		return true;
 	}
 }

framework/caching/ZendDataCache.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * CZendDataCache class file
+ * ZendDataCache class file
  *
  * @link http://www.yiiframework.com/
  * @copyright Copyright &copy; 2008-2012 Yii Software LLC
@@ -10,32 +10,19 @@
 namespace yii\caching;
 
 /**
- * CZendDataCache implements a cache application module based on the Zend Data Cache
- * delivered with {@link http://www.zend.com/en/products/server/ ZendServer}.
+ * ZendDataCache provides Zend data caching in terms of an application component.
  *
- * To use this application component, the Zend Data Cache PHP extension must be loaded.
+ * To use this application component, the [Zend Data Cache PHP extensionn](http://www.zend.com/en/products/server/)
+ * must be loaded.
  *
- * See {@link CCache} manual for common cache operations that are supported by CZendDataCache.
+ * See [[Cache]] for common cache operations that ZendDataCache supports.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class CZendDataCache extends CCache
+class ZendDataCache extends Cache
 {
 	/**
-	 * Initializes this application component.
-	 * This method is required by the {@link IApplicationComponent} interface.
-	 * It checks the availability of Zend Data Cache.
-	 * @throws CException if Zend Data Cache extension is not loaded.
-	 */
-	public function init()
-	{
-		parent::init();
-		if(!function_exists('zend_shm_cache_store'))
-			throw new CException(Yii::t('yii','CZendDataCache requires PHP Zend Data Cache extension to be loaded.'));
-	}
-
-	/**
 	 * Retrieves a value from cache with a specified key.
 	 * This is the implementation of the method declared in the parent class.
 	 * @param string $key a unique key identifying the cached value
@@ -72,7 +59,7 @@ class CZendDataCache extends CCache
 	 */
 	protected function addValue($key, $value, $expire)
 	{
-		return (NULL === zend_shm_cache_fetch($key)) ? $this->setValue($key,$value,$expire) : false;
+		return zend_shm_cache_fetch($key) === null ? $this->setValue($key, $value, $expire) : false;
 	}
 
 	/**
@@ -90,7 +77,6 @@ class CZendDataCache extends CCache
 	 * Deletes all values from cache.
 	 * This is the implementation of the method declared in the parent class.
 	 * @return boolean whether the flush operation was successful.
-	 * @since 1.1.5
 	 */
 	protected function flushValues()
 	{