diff --git a/enforcer.go b/enforcer.go
index d78acaf..58c8223 100644
--- a/enforcer.go
+++ b/enforcer.go
@@ -154,6 +154,14 @@ func (e *Enforcer) SetWatcher(watcher persist.Watcher) {
 	e.watcher = watcher
 }
 
+func (e *Enforcer) SetUpdatableWatcher(watcher persist.UpdatableWatcher) {
+	e.updatableWatcher = watcher
+}
+
+func (e *Enforcer) GetUpdatableWatcher() persist.UpdatableWatcher {
+	return e.updatableWatcher
+}
+
 func (e *Enforcer) GetLogger() log.Logger {
 	return e.logger
 }
diff --git a/persist/watcher_update.go b/persist/watcher_update.go
index 0d223b7..32bd494 100644
--- a/persist/watcher_update.go
+++ b/persist/watcher_update.go
@@ -2,8 +2,8 @@ package persist
 
 // UpdatableWatcher called when data updated
 type UpdatableWatcher interface {
-	UpdateForSetStr(key string, value interface{}, timeout int64) error
-	UpdateForUpdateStr(key string, value interface{}) error
+	UpdateForSetStr(key string, value string, timeout int64) error
+	UpdateForUpdateStr(key string, value string) error
 	UpdateForSet(key string, value interface{}, timeout int64) error
 	UpdateForUpdate(key string, value interface{}) error
 	UpdateForDelete(key string) error