--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/emailuis/uicomponents/inc/fstreeobserver.h	Thu Dec 17 08:39:21 2009 +0200
@@ -0,0 +1,109 @@
+/*
+* 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:  An observer interface for the tree data model.
+*
+*/
+
+
+#ifndef M_FSTREEOBSERVER_H
+#define M_FSTREEOBSERVER_H
+
+
+/**
+ * MFsTreeObserver defines an interface which is used to observe tree events.
+ * 
+ * Observer of the tree is notified of changes in the tree structure
+ * through this interface with appropriate events.
+ * 
+ * @code
+ *
+ * @endcode
+ *
+ * @lib 
+ */
+NONSHARABLE_CLASS( MFsTreeObserver )
+    {
+public:
+
+    enum TFsTreeEvent
+        {
+        /** 
+         * Item was added to the tree. 
+         * The visible items list should be updated if needed.
+         */
+        EFsTreeItemAdded,
+        
+        /** 
+         * Node was added to the tree. 
+         * The visible items list should be updated if needed.
+         */
+        EFsTreeNodeAdded,
+        
+        /**
+         * Item was removed from the tree.
+         * The visible items list should be updated if needed.
+         */
+        EFsTreeItemRemoved,
+        
+        /**
+         * Node was removed from the tree.
+         * The visible items list should be updated if needed.
+         */
+        EFsTreeNodeRemoved,
+        
+        /**
+         * All items will be removed from the tree.
+         * The visible items list should be updated..
+         */
+        EFsTreeRemovedAll,
+        
+        /**
+         * Item's/Node's data has changed.
+         * The visible items list should be updated if needed.
+         */
+        EFsTreeItemDataChanged,
+        
+        /**
+         * Item data's visualizer has changed.
+         * The visible items list should be updated if needed.
+         */
+        EFsTreeItemVisualizerChanged
+        };
+    
+public:
+    
+    /**
+     * Observer of the tree is notified of changes in the tree structure
+     * through this function.
+     * 
+     * @param aEvent Event which happend in the tree structure.
+     * @param aId Id of the node/item associated with the event.
+     */
+    struct TFsTreeEventParams
+        {
+        TFsTreeEventParams(TFsTreeItemId aItemId, TFsTreeItemId aTargetNodeId, TInt aIndex ) :
+        iItemId(aItemId), iTargetNodeId(aTargetNodeId), iIndex(aIndex) {};
+        
+        TFsTreeItemId iItemId;
+        TFsTreeItemId iTargetNodeId; 
+        TInt iIndex;
+        };
+    
+    virtual void TreeEventL( const TFsTreeEvent aEvent, 
+            const TFsTreeEventParams& aParams ) = 0;
+    
+    };
+    
+     
+#endif // M_FSTREEOBSERVER_H