diff -r b183ec05bd8c -r 19bba8228ff0 devicediagnosticsfw/diagframework/inc/diagenginestatemachineobserver.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/devicediagnosticsfw/diagframework/inc/diagenginestatemachineobserver.h	Wed Sep 01 12:27:42 2010 +0100
@@ -0,0 +1,79 @@
+/*
+* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). 
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:  Class declaration for MStateMachineObserver
+*
+*/
+
+
+#ifndef DIAGENGINESTATEMACHINEOBSERVER_H
+#define DIAGENGINESTATEMACHINEOBSERVER_H
+
+// system include
+
+// user include
+#include "diagenginestates.h"   // DiagFwInternal::TState
+#include "diagengineevents.h"   // DiagFwInternal::TEvent
+
+namespace DiagFwInternal
+    {
+// forward declaration
+class CEventBasic;
+
+/**
+ *  Diagnostics Framework Engine State Machine Observer
+ *
+ *  This interface is called by CDiagEngineStateMachine to notify
+ *  its client of state changes and events.
+ *
+ *  @since S60 v5.0
+ */
+class MStateMachineObserver
+    {
+public:
+    /**
+    * Notify state machine client that state machine has entered a new state.
+    *
+    * @param aPreviousState     Previous state.
+    * @param aCurrentState      Current state. (new state.)
+    * @param aEventPreview  Event that caused state change. Note that
+    *   this is just a preview.  HandleEventL() will be called with the same
+    *   event later on.
+    */
+    virtual void HandleStateChangedL( TState aPreviousState, 
+                                      TState aCurrentState,
+                                      const CEventBasic& aEventPreview ) = 0;
+
+    /**
+    * Notify state machine client that a new event is received.
+    *
+    * @param aEvent        New event.
+    */
+    virtual void HandleEventL( CEventBasic& aEvent ) = 0;
+
+    /**
+    * Notify state machine client that an abnormal error has occured.
+    * Client can handle the error and return appropriate error state.
+    *
+    * @param aCurrentState Current state.
+    * @param aError        Error number.
+    * @return TState       New state to go to.
+    */
+    virtual TState HandleError( TState aCurrentState, TInt aError ) = 0;
+    };
+    } // end of namespace DiagFwInternal
+    
+#endif // DIAGENGINESTATEMACHINEOBSERVER_H
+
+// End of File
+