. namespace core_cache; /** * Cache store feature: key awareness. * * This is a feature that cache stores and cache loaders can both choose to implement. * If a cache store implements this then it will be made responsible for tests for items within the cache. * If the cache store being used doesn't implement this then it will be the responsibility of the cache loader to use the * equivalent get methods to mimick the functionality of these tests. * * Cache stores should only override these methods if they natively support such features or if they have a better performing * means of performing these tests than the handling that would otherwise take place in the cache_loader. * * Can be implemented by classes already implementing cache_store. * * @package core_cache * @copyright Sam Hemelryk * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ interface key_aware_cache_interface { /** * Test is a cache has a key. * * The use of the has methods is strongly discouraged. In a high load environment the cache may well change between the * test and any subsequent action (get, set, delete etc). * Instead it is recommended to write your code in such a way they it performs the following steps: *

*
1. Attempt to retrieve the information.
*
2. Generate the information.
*
3. Attempt to set the information
*

* * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param string|int $key * @return bool True if the cache has the requested key, false otherwise. */ public function has($key); /** * Test if a cache has at least one of the given keys. * * It is strongly recommended to avoid the use of this function if not absolutely required. * In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param array $keys * @return bool True if the cache has at least one of the given keys */ public function has_any(array $keys); /** * Test is a cache has all of the given keys. * * It is strongly recommended to avoid the use of this function if not absolutely required. * In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). * * Its also worth mentioning that not all stores support key tests. * For stores that don't support key tests this functionality is mimicked by using the equivalent get method. * Just one more reason you should not use these methods unless you have a very good reason to do so. * * @param array $keys * @return bool True if the cache has all of the given keys, false otherwise. */ public function has_all(array $keys); } // Alias this class to the old name. // This file will be autoloaded by the legacyclasses autoload system. // In future all uses of this class will be corrected and the legacy references will be removed. class_alias(key_aware_cache_interface::class, \cache_is_key_aware::class);