/*

* Copyright (c) 2007-2008 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 header for CWsfScreenSaverWatcher

*

*/

#ifndef C_WSFSCREENSAVERWACTHER_H

#define C_WSFSCREENSAVERWACTHER_H

#include <e32base.h>

#include <e32property.h>

//  FORWARD DECLARATIONS

class MWsfScreenSaverStateObserver;

/**

* Active object class which monitors screen saver activity and notifies 

* the observer when changes occur.

*

* @lib wsfmodel.lib

* @since S60 5.0

*/

NONSHARABLE_CLASS( CWsfScreenSaverWatcher ): public CActive

    {

    public:     // Constructors

        /**

        * Factory function.

        * @since S60 5.0

        * @param aObserver The object to notify when changes occur.

        * @return Class instance.

        */

        static CWsfScreenSaverWatcher* NewL( 

                                    MWsfScreenSaverStateObserver& aObserver );

        /**

        * Factory function.

        * @since S60 5.0

        * @param aObserver The object to notify when changes occur.

        * @return Class instance.

        */

        static CWsfScreenSaverWatcher* NewLC( 

                                    MWsfScreenSaverStateObserver& aObserver );

        ~CWsfScreenSaverWatcher();

    private: // Constructors

        /**

        * Constructor.

        * @since S60 5.0

        * @param aObserver The object to notify when changes occur.

        */

        CWsfScreenSaverWatcher( MWsfScreenSaverStateObserver& aObserver );

        void ConstructL();    

    public: 

        /**

        * Start receiving events from screensaver

        * @since S60 5.0

        */

        void StartStatusScanning();

    protected:  // from CActive

        void RunL();

        void DoCancel();

        TInt RunError( TInt aError );

    private:    // Data

        /**

        * Handle to the screen saver property value

        */

        RProperty iProperty;

        /**

        * The object to notify when changes occur. Not owned.

        */

        MWsfScreenSaverStateObserver* iObserver;

    };

#endif // C_WSFSCREENSAVERWACTHER_H