+template <class T>
+T* HistoryHandler<T>::GetPrevious()
+{
+ if(!undoStack.empty()){
+ return undoStack.back();
+ }
+ return NULL;
+}
+
+template <class T>
+T* HistoryHandler<T>::GetNext()
+{
+ if(!redoStack.empty()){
+ return redoStack.back();
+ }
+ return NULL;
+}
+