--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Translation;
+
+/**
+ * MetadataAwareInterface.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+interface MetadataAwareInterface
+{
+ /**
+ * Gets metadata for the given domain and key.
+ *
+ * Passing an empty domain will return an array with all metadata indexed by
+ * domain and then by key. Passing an empty key will return an array with all
+ * metadata for the given domain.
+ *
+ * @param string $key The key
+ * @param string $domain The domain name
+ *
+ * @return mixed The value that was set or an array with the domains/keys or null
+ */
+ public function getMetadata($key = '', $domain = 'messages');
+
+ /**
+ * Adds metadata to a message domain.
+ *
+ * @param string $key The key
+ * @param mixed $value The value
+ * @param string $domain The domain name
+ */
+ public function setMetadata($key, $value, $domain = 'messages');
+
+ /**
+ * Deletes metadata for the given key and domain.
+ *
+ * Passing an empty domain will delete all metadata. Passing an empty key will
+ * delete all metadata for the given domain.
+ *
+ * @param string $key The key
+ * @param string $domain The domain name
+ */
+ public function deleteMetadata($key = '', $domain = 'messages');
+}