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<?php
/**
* TAPCCache class file
*
* @author Alban Hanry <compte_messagerie@hotmail.com>
* @link http://www.pradosoft.com/
* @copyright Copyright © 2005 PradoSoft
* @license http://www.pradosoft.com/license/
* @version $Revision: $ $Date: $
* @package System.Caching
*/
/**
* TAPCCache class
*
* TAPCCache implements a cache application module based on {@link http://www.php.net/apc APC}.
*
* By definition, cache does not ensure the existence of a value
* even if it never expires. Cache is not meant to be an persistent storage.
*
* To use this module, the APC PHP extension must be loaded and set in the php.ini file the following:
* <code>
* apc.cache_by_default=0
* </code>
*
* Some usage examples of TAPCCache are as follows,
* <code>
* $cache=new TAPCCache; // TAPCCache may also be loaded as a Prado application module
* $cache->init(null);
* $cache->add('object',$object);
* $object2=$cache->get('object');
* </code>
*
* If loaded, TAPCCache will register itself with {@link TApplication} as the
* cache module. It can be accessed via {@link TApplication::getCache()}.
*
* TAPCCache may be configured in application configuration file as follows
* <module id="cache" class="System.Caching.TAPCCache" />
*
* @author Alban Hanry <compte_messagerie@hotmail.com>
* @version $Revision: $ $Date: $
* @package System.Caching
* @since 3.0b
*/
class TAPCCache extends TModule implements ICache
{
/**
* @var boolean if the module is initialized
*/
private $_initialized=false;
/**
* @var string a unique prefix used to identify this cache instance from the others
*/
protected $_prefix=null;
/**
* Initializes this module.
* This method is required by the IModule interface.
* @param TXmlElement configuration for this module, can be null
* @throws TConfigurationException if apc extension is not installed or not started, check your php.ini
*/
public function init($config)
{
if(!extension_loaded('apc'))
throw new TConfigurationException('apccache_extension_required');
$application=$this->getApplication();
$this->_prefix=$application->getUniqueID();
$application->setCache($this);
$this->_initialized=true;
}
/**
* Retrieves a value from cache with a specified key.
* @return mixed the value stored in cache, false if the value is not in the cache or expired.
*/
public function get($key)
{
if(($value=apc_fetch($this->_prefix.$key))!==false)
return Prado::unserialize($value);
else
return $value;
}
/**
* Stores a value identified by a key into cache.
* If the cache already contains such a key, the existing value and
* expiration time will be replaced with the new ones.
*
* @param string the key identifying the value to be cached
* @param mixed the value to be cached
* @param integer the expiration time of the value,
* 0 means never expire,
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
public function set($key,$value,$expiry=0)
{
return apc_store($this->_prefix.$key,Prado::serialize($value),$expiry);
}
/**
* Stores a value identified by a key into cache if the cache does not contain this key.
* APC does not support this mode. So calling this method will raise an exception.
* @param string the key identifying the value to be cached
* @param mixed the value to be cached
* @param integer the expiration time of the value,
* 0 means never expire,
* @return boolean true if the value is successfully stored into cache, false otherwise
* @throw new TNotSupportedException if this method is invoked
*/
public function add($key,$value,$expiry=0)
{
throw new TNotSupportedException('apccache_add_unsupported');
}
/**
* Stores a value identified by a key into cache only if the cache contains this key.
* The existing value and expiration time will be overwritten with the new ones.
* APC does not support this mode. So calling this method will raise an exception.
* @param string the key identifying the value to be cached
* @param mixed the value to be cached
* @param integer the expiration time of the value,
* 0 means never expire,
* @return boolean true if the value is successfully stored into cache, false otherwise
* @throw new TNotSupportedException if this method is invoked
*/
public function replace($key,$value,$expiry=0)
{
throw new TNotSupportedException('apccache_replace_unsupported');
}
/**
* Deletes a value with the specified key from cache
* @param string the key of the value to be deleted
* @return boolean if no error happens during deletion
*/
public function delete($key)
{
return apc_delete($this->_prefix.$key);
}
/**
* Deletes all values from cache.
*/
public function flush()
{
return apc_clear_cache('user');
}
}
?>
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