<?php
namespace Doctrine\Common\Cache;
/**
* Interface for cache drivers.
*
* @link www.doctrine-project.org
*/
interface Cache
{
public const STATS_HITS = 'hits';
public const STATS_MISSES = 'misses';
public const STATS_UPTIME = 'uptime';
public const STATS_MEMORY_USAGE = 'memory_usage';
public const STATS_MEMORY_AVAILABLE = 'memory_available';
/**
* Only for backward compatibility (may be removed in next major release)
*
* @deprecated
*/
public const STATS_MEMORY_AVAILIABLE = 'memory_available';
/**
* Fetches an entry from the cache.
*
* @param string $id The id of the cache entry to fetch.
*
* @return mixed The cached data or FALSE, if no cache entry exists for the given id.
*/
public function fetch($id);
/**
* Tests if an entry exists in the cache.
*
* @param string $id The cache id of the entry to check for.
*
* @return bool TRUE if a cache entry exists for the given cache id, FALSE otherwise.
*/
public function contains($id);
/**
* Puts data into the cache.
*
* If a cache entry with the given id already exists, its data will be replaced.
*
* @param string $id The cache id.
* @param mixed $data The cache entry/data.
* @param int $lifeTime The lifetime in number of seconds for this cache entry.
* If zero (the default), the entry never expires (although it may be deleted from the cache
* to make place for other entries).
*
* @return bool TRUE if the entry was successfully stored in the cache, FALSE otherwise.
*/
public function save($id, $data, $lifeTime = 0);
/**
* Deletes a cache entry.
*
* @param string $id The cache id.
*
* @return bool TRUE if the cache entry was successfully deleted, FALSE otherwise.
* Deleting a non-existing entry is considered successful.
*/
public function delete($id);
/**
* Retrieves cached information from the data store.
*
* The server's statistics array has the following values:
*
* - <b>hits</b>
* Number of keys that have been requested and found present.
*
* - <b>misses</b>
* Number of items that have been requested and not found.
*
* - <b>uptime</b>
* Time that the server is running.
*
* - <b>memory_usage</b>
* Memory used by this server to store items.
*
* - <b>memory_available</b>
* Memory allowed to use for storage.
*
* @return array|null An associative array with server's statistics if available, NULL otherwise.
*/
public function getStats();
}