diff --git a/src/File.php b/src/File.php
new file mode 100644
index 0000000..0187594
--- /dev/null
+++ b/src/File.php
@@ -0,0 +1,40 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<mike@phpdoc.org>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection;
+
+/**
+ * Interface for files processed by the ProjectFactory
+ */
+interface File
+{
+    /**
+     * Returns the content of the file as a string.
+     *
+     * @return string
+     */
+    public function getContents();
+
+    /**
+     * Returns md5 hash of the file.
+     *
+     * @return string
+     */
+    public function md5();
+
+    /**
+     * Returns an relative path to the file.
+     *
+     * @return string
+     */
+    public function path();
+}
diff --git a/src/ProjectFactory.php b/src/ProjectFactory.php
index f2c091d..5602f84 100644
--- a/src/ProjectFactory.php
+++ b/src/ProjectFactory.php
@@ -20,7 +20,7 @@ interface ProjectFactory
      * Creates a project from the set of files.
      *
      * @param string $name
-     * @param string[] $files
+     * @param File[] $files
      * @return Project
      */
     public function create($name, array $files);