Release 18.08
diff --git a/src/armnn/Observable.hpp b/src/armnn/Observable.hpp
new file mode 100644
index 0000000..8f33c0b
--- /dev/null
+++ b/src/armnn/Observable.hpp
@@ -0,0 +1,67 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// See LICENSE file in the project root for full license information.
+//
+#pragma once
+
+#include "IGraphObservable.hpp"
+#include "Graph.hpp"
+
+namespace armnn
+{
+
+template <typename ObservedType>
+class GraphObservable : public IGraphObservable
+{
+public:
+ using Iterator = typename std::list<ObservedType>::const_iterator;
+
+ GraphObservable(Graph& subject, GraphEvent notifyOnEvent)
+ : m_Subject(&subject)
+ {
+ m_NotifyOnEvent = notifyOnEvent;
+ m_Subject->AttachObservable(this, m_NotifyOnEvent);
+ };
+
+ void Clear() { m_ObservedObjects.clear(); };
+
+ Iterator begin() { return m_ObservedObjects.begin(); }
+
+ Iterator end() { return m_ObservedObjects.end(); }
+
+protected:
+ ~GraphObservable()
+ {
+ if (m_Subject)
+ {
+ m_Subject->DetachObservable(this, m_NotifyOnEvent);
+ }
+ }
+
+ GraphEvent m_NotifyOnEvent;
+ Graph* m_Subject;
+ std::list<ObservedType> m_ObservedObjects;
+};
+
+class AddedLayerObservable : public GraphObservable<Layer*>
+{
+public:
+ explicit AddedLayerObservable(Graph& subject)
+ : GraphObservable<Layer*>(subject, GraphEvent::LayerAdded)
+ {};
+
+ void Update(Layer* graphLayer) override;
+};
+
+class ErasedLayerNamesObservable : public GraphObservable<std::string>
+{
+public:
+ explicit ErasedLayerNamesObservable(Graph& subject)
+ : GraphObservable<std::string>(subject, GraphEvent::LayerErased)
+ {};
+
+ void Update(Layer* graphLayer) override;
+};
+
+} //namespace armnn
+