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vendor/yiisoft/yii2/caching/DummyCache.php

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+<?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.
+ *
+ * For more details and usage information on Cache, see the [guide article on caching](guide:caching-overview).
+ *
+ * @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 $key a unique key identifying the cached value
+     * @return mixed|false the value stored in cache, false if the value is not in the cache or expired.
+     */
+    protected function getValue($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 mixed $value the value to be cached
+     * @param int $duration the number of seconds in which the cached value will expire. 0 means never expire.
+     * @return bool true if the value is successfully stored into cache, false otherwise
+     */
+    protected function setValue($key, $value, $duration)
+    {
+        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 mixed $value the value to be cached
+     * @param int $duration the number of seconds in which the cached value will expire. 0 means never expire.
+     * @return bool true if the value is successfully stored into cache, false otherwise
+     */
+    protected function addValue($key, $value, $duration)
+    {
+        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 $key the key of the value to be deleted
+     * @return bool if no error happens during deletion
+     */
+    protected function deleteValue($key)
+    {
+        return true;
+    }
+
+    /**
+     * Deletes all values from cache.
+     * This is the implementation of the method declared in the parent class.
+     * @return bool whether the flush operation was successful.
+     */
+    protected function flushValues()
+    {
+        return true;
+    }
+}