/*

* Copyright (c) 2005, 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:  Central repository key watcher class.

*

*/

#ifndef USBCLASSCHANGEUIPLUGINCRWATCHER_H

#define USBCLASSCHANGEUIPLUGINCRWATCHER_H

// INCLUDES

#include <centralrepository.h>

// FORWARD DECLARATIONS

class CRepository; 

/**

* A callback interface for informing change of a setting in Central Repository

*/

class MUSBUICRSettingObserver

    {

    public: // New functions

        /**

        * Informs the observer that a setting has been changed. 

        * @param aKey The changed key. 

        * @return None.

        */

        virtual void SettingChangedL( TUint32 aKey ) = 0;

    };

/**

* CUSBClassChangeUIPluginCRWatcher detects a change of the value of the CR key.

* CUSBClassChangeUIPluginCRWatcher provides CActive object that is used to 

* detect when the value of the selected key in Central Repository is changed 

* by the USBWatcher. One observer can be notified by one or more

* USBClassChangeUIPluginCRWatcher objects, each watching different keys. 

*/

class CUSBClassChangeUIPluginCRWatcher : public CActive

    {

    public:

        /**

        * Factory method NewL

        * @param aOwner     The observer to be notified on the change. 

        * @param aKey       The Central Repository key to be watched. 

        * @param aOneShot   If false, the listening is restarted after change.

        * @return           The new watcher object. 

        */

        static CUSBClassChangeUIPluginCRWatcher* NewL( 

            MUSBUICRSettingObserver& aOwner, TUint32 aKey, 

            TBool aOneShot = EFalse);

        /**

        * Starts listening for notifications. If already listening, nothing 

        * happens.

        */

        void StartListeningL();

        /**

        * Stops listening for notifications. If already stopped, nothing 

        * happens.

        * @param none

        * @return none 

        */

        void StopListening();

        /**

        * C++ default constructor

        * @param aOwner     The observer to be notified on the change. 

        * @param aKey       The Central Repository key to be watched. 

        * @param aOneShot   If false, the listening is restarted after change.

        */

        CUSBClassChangeUIPluginCRWatcher( 

            MUSBUICRSettingObserver& aOwner, TUint32 aKey, 

            TBool aOneShot = EFalse);

        /**

        * Destructor.

        */

        virtual ~CUSBClassChangeUIPluginCRWatcher();

    private:

        /**

        * Constructor.

        * @param none

        */

        void ConstructL();

        /**

        *	Implements CActive

        *   If this is not a one-shot CR watcher, the listening is restarted.

        *	@param none

        *	@return none

        */

        void RunL();

        /**

        *	Implements CActive

        *	@param aError the error returned

        *	@return error

        */

        TInt RunError(TInt aError);

        /**

        *	Implements CActive

        *	@param none

        *	@return none

        */

        void DoCancel();

    private:

        /** USB Watcher repository access */

        CRepository* iPersonalityRepository;

        /** The observer to be notified */

        MUSBUICRSettingObserver& iOwner;

        /** The repository key to be watcher */

        TUint32 iKey;

        /** If iOneShot is false, listening is restarted on notification */

        TBool iOneShot;

    };

#endif      // USBCLASSCHANGEUIPLUGINCRWATCHER_H

// End of File