--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/calendarui/inc/PropertyObserver.h	Tue Feb 02 10:12:19 2010 +0200
@@ -0,0 +1,162 @@
+/*
+* Copyright (c) 2002, 2003 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: Property Observer class for handling property change events.
+ *
+*/
+
+
+
+#ifndef CPROPERTYOBSERVER_H
+#define CPROPERTYOBSERVER_H
+
+// INCLUDES
+#include <e32base.h>
+#include <e32property.h>
+
+// CLASS DECLARATION
+
+/**
+ * MPropertyChangeHandler.
+ * Abstract interface for handling property change events.
+ **/
+NONSHARABLE_CLASS( MPropertyChangeHandler )
+{
+ public:
+    /**
+     * This is a callback function which is called when a property is changed.
+     *
+     * @param aCategory  UID of the category.
+     * @param aKey       changed key
+     * @param aValue     the new value
+     *
+     * Note! references aKey and aValue are only valid while executing
+     * HandlePropertyChange(). After that the data in which they refer can change.
+     **/
+    virtual void HandlePropertyChange(const TUid& aCategory, const TUint& aKey, const TInt& aValue) = 0;
+
+};
+
+
+// CLASS DECLARATION
+
+/**
+ * ?one_line_short_description.
+ * ?other_description_lines
+ *
+ * @since Series 60 3.0
+ **/
+NONSHARABLE_CLASS(CPropertyObserver) : public CActive
+{
+ public:  // Constructors and destructor
+    /**
+     * Two-phased constructor.
+     * @since Series 60 3.0
+     * @param ?arg1 ?description
+     * @param ?arg2 ?description
+     **/
+    static CPropertyObserver* NewL(MPropertyChangeHandler& aHandler, const TUid& aCategory, const TUint& aKey, const TBool aSkipValue=EFalse)
+    {
+        CPropertyObserver* self = new( ELeave )CPropertyObserver( aHandler, aCategory, aKey, aSkipValue );
+        CleanupStack::PushL( self );
+        self->ConstructL();
+        CleanupStack::Pop( self );
+        return self;
+    };
+
+    /**
+     * Destructor.
+     **/
+    ~CPropertyObserver()
+    {
+        Deque();
+        iProperty.Cancel();
+        iProperty.Close();
+    };
+
+ private:
+    /**
+     * C++ default constructor overload.
+     **/
+    CPropertyObserver(MPropertyChangeHandler& aHandler, const TUid& aCategory, const TUint& aKey, const TBool aSkipValue)
+    : CActive( CActive::EPriorityStandard ),
+      iCategory( aCategory ),
+      iKey( aKey ),
+      iHandler( aHandler ),
+      iSkipValue( aSkipValue )
+    {
+    };
+
+    /**
+     * By default Symbian 2nd phase constructor is private.
+     **/
+    void ConstructL(void)
+    {
+        CActiveScheduler::Add( this );
+
+        User::LeaveIfError( iProperty.Attach( iCategory, iKey ) );
+
+        //NotifyCurrentValue(); // notify initial value
+
+        // Start observing...
+        Subscribe();
+    };
+
+ protected:  // Functions from base classes
+    /**
+     * From CActive ?member_description
+     **/
+    inline void RunL(void);
+
+    /**
+     * From CActive ?member_description
+     **/
+    inline void DoCancel(void);
+
+ private:  // New functions
+    /**
+     * ?member_description.
+     * @since Series 60 3.0
+     **/
+    inline void Subscribe(void);
+
+    /**
+     * ?member_description.
+     * @since Series 60 3.0
+     **/
+    inline void NotifyCurrentValue(void);
+
+ private:  // Data
+    // ?one_line_short_description_of_data
+    RProperty iProperty;
+
+    // ?one_line_short_description_of_data
+    const TUid iCategory;
+
+    // ?one_line_short_description_of_data
+    const TUint iKey;
+
+    // ?one_line_short_description_of_data
+    MPropertyChangeHandler& iHandler;
+
+    // ?one_line_short_description_of_data
+    const TBool iSkipValue;
+
+};
+
+#include "PropertyObserver.inl"
+
+#endif  // CPROPERTYOBSERVER_H
+
+
+// End of File