diff --git a/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php b/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php
index abd68ed6c4..f6b99a16ae 100644
--- a/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php
+++ b/src/Symfony/Component/Routing/Loader/AnnotationDirectoryLoader.php
@@ -66,12 +66,16 @@ class AnnotationDirectoryLoader extends AnnotationFileLoader
      */
     public function supports($resource, $type = null)
     {
+        if (!is_string($resource)) {
+            return false;
+        }
+        
         try {
             $path = $this->locator->locate($resource);
         } catch (\Exception $e) {
             return false;
         }
 
-        return is_string($resource) && is_dir($path) && (!$type || 'annotation' === $type);
+        return is_dir($path) && (!$type || 'annotation' === $type);
     }
 }