--- /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;
+
+class Cache implements CacheInterface
+{
+ private $cache = array();
+
+ /**
+ * {@inheritdoc}
+ */
+ public function exists($placeholder)
+ {
+ if (is_array($placeholder)) {
+ throw new \RuntimeException('Placeholder is an array');
+ }
+
+ return array_key_exists((string) $placeholder, $this->cache);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function get($placeholder)
+ {
+ if (is_array($placeholder)) {
+ throw new \RuntimeException('Placeholder is an array');
+ }
+
+ return array_key_exists((string) $placeholder, $this->cache)
+ ? $this->cache[(string) $placeholder]
+ : null;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function set($placeholder, $value = null)
+ {
+ if (is_array($placeholder)) {
+ throw new \RuntimeException('Placeholder is an array');
+ }
+ $this->cache[(string) $placeholder] = $value;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function flush()
+ {
+ $this->cache = array();
+ }
+}