--- /dev/null
+<?php
+
+/*
+ * This file is a part of dflydev/placeholder-resolver.
+ *
+ * (c) Dragonfly Development Inc.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Dflydev\PlaceholderResolver\Cache;
+
+interface CacheInterface
+{
+ /**
+ * Does specified placeholder exist?
+ *
+ * @param string $placeholder
+ *
+ * @return bool
+ */
+ public function exists($placeholder);
+
+ /**
+ * Get placeholder's value
+ *
+ * @param string $placeholder
+ *
+ * @return string|null
+ */
+ public function get($placeholder);
+
+ /**
+ * Set placeholder's value
+ *
+ * @param string $placeholder
+ * @param string|null $value
+ *
+ * @return string|null
+ */
+ public function set($placeholder, $value = null);
+
+ /**
+ * Flush cache
+ */
+ public function flush();
+}