/*

* Copyright (c) 2002-2006 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:  Interface for Publish and suscripe change notifier.

*

*/

#ifndef MSATSYSTEMSTATECHANGENOTIFIER_H

#define MSATSYSTEMSTATECHANGENOTIFIER_H

//  INCLUDES

#include <e32std.h>

// CONSTANTS

// Indicates that the observer doesn't want to specify any value, when it should

// be notified. In this case, the changed value is sent to observer

const TInt KNotifyValueNotSet = -1;

// CLASS DECLARATION

/**

*  Change notifier for Publish & Subscribe.

*

*  @lib SatSystemState

*  @since Series 60 3.0

*/

class MSatSystemStateChangeNotifier

    {

    public:  // Constructors and destructor

        /**

        * Destructor.

        */

        virtual ~MSatSystemStateChangeNotifier() {};

    public: // New functions

        /**

        * Request a notification of a change in system state.

        * The request is standing as long as it is canceled.

        */

        virtual void NotifyChangeL() = 0;

        /**

        * Cancels the notification request.

        */

        virtual void CancelNotify() = 0;

        /**

        * Gets the current value.

        * @return Current value for earlier request.

        */

        virtual TInt GetValueInt() { return KNotifyValueNotSet; };

    protected:  // New functions

        /**

        * C++ default constructor.

        */

        MSatSystemStateChangeNotifier() {};

    private:

        // Prohibit copy constructor if not deriving from CBase.

        MSatSystemStateChangeNotifier( const MSatSystemStateChangeNotifier& );

        // Prohibit assigment operator if not deriving from CBase.

        MSatSystemStateChangeNotifier& operator=( const MSatSystemStateChangeNotifier& );

    };

#endif      // MSATSYSTEMSTATECHANGENOTIFIER_H

// End of File