From 0b0d258afd4ef8c9b42d03d5e43291d7214eeed6 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sat, 19 Dec 2015 11:31:59 +0100
Subject: [PATCH] + make method cancelObservation() not pure virtual

---
 src/App/DocumentObserver.cpp | 4 ++++
 src/App/DocumentObserver.h   | 6 +++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/App/DocumentObserver.cpp b/src/App/DocumentObserver.cpp
index 88a961c8d..25e2eb2f3 100644
--- a/src/App/DocumentObserver.cpp
+++ b/src/App/DocumentObserver.cpp
@@ -302,3 +302,7 @@ void DocumentObjectObserver::slotChangedObject(const App::DocumentObject&,
                                                const App::Property&)
 {
 }
+
+void DocumentObjectObserver::cancelObservation()
+{
+}
diff --git a/src/App/DocumentObserver.h b/src/App/DocumentObserver.h
index 08cb7851d..804d91d9f 100644
--- a/src/App/DocumentObserver.h
+++ b/src/App/DocumentObserver.h
@@ -202,7 +202,11 @@ private:
     virtual void slotDeletedObject(const App::DocumentObject& Obj);
     /** The property of an observed object has changed */
     virtual void slotChangedObject(const App::DocumentObject& Obj, const App::Property& Prop);
-    virtual void cancelObservation() = 0;
+    /** This method gets called when all observed objects are deleted or the whole document is deleted.
+      * This method can be re-implemented to perform an extra step like closing a dialog tht observes
+      * a document.
+      */
+    virtual void cancelObservation();
 
 private:
     std::set<App::DocumentObject*> _objects;