diff --git a/cmis_common/lib/cmis_repository_wrapper.php b/cmis_common/lib/cmis_repository_wrapper.php
index feb6de3..bfaa31f 100644
--- a/cmis_common/lib/cmis_repository_wrapper.php
+++ b/cmis_common/lib/cmis_repository_wrapper.php
@@ -418,9 +418,9 @@ class CMISService extends CMISRepositoryWrapper {
 		return $obj->properties["cmis:name"];
 	}	
 	function getLink($objectId,$linkName) {
-		if ($this->_link_cache[$objectId][$linkName]) {
-			return $this->_link_cache[$objectId][$linkName];
-		}
+		if (array_key_exists($objectId, $this->_link_cache)) {
+                        return $this->_link_cache[$objectId][$linkName];
+                }
 		$obj=$this->getObject($objectId);
 		return $obj->links[$linkName];
 	}