<?php /** * @link http://www.yiiframework.com/ * @copyright Copyright (c) 2008 Yii Software LLC * @license http://www.yiiframework.com/license/ */ namespace yii\caching; /** * DummyCache is a placeholder cache component. * * 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::$app->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 DummyCache extends Cache { /** * Retrieves a value from cache with a specified key. * This is the implementation of the method declared in the parent class. * @param string $key a unique key identifying the cached value * @return string|boolean the value stored in cache, false if the value is not in the cache or expired. */ protected function getValue($key) { return 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 true; } /** * 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 true; } /** * 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 true; } /** * 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. */ protected function flushValues() { return true; } }