/*

* Copyright (c) 2005 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:  CVASDBMonitor class is an active object that is a wrapper around 

*               the RDBNotifier class. Events from RDBNotifier are handled by 

*               encapsulating them in a CNssVASDBEvent object and passing it to all 

*               its observers. In addition to the events provided by RDBNotifier, 

*               CVASDBMonitor also provides additional events when a entry is added,

*               changed or deleted from the VAS DB. CVASDBMonitor owns the list of 

*               observers of the VAS DB.

*

*/

#ifndef CNSSVASDBEVENTMONITOR_H

#define CNSSVASDBEVENTMONITOR_H

//  INCLUDES

#include <d32dbms.h>

#include "nssvascoreconstant.h"

#include "nssvascvasdbevent.h"

#include "nssvasmvasdatabaseobserver.h"

#include "nssvasctag.h"

// CLASS DECLARATION

/**

*  CNssVASDBEventMonitor is an active object responsible for observing VAS database changes

*  and notifying all registerted observers of the change.

*  @lib NssVASApi.lib

*  @since 2.8

*/

class CNssVASDBEventMonitor :public CActive

    {

    public:  // Constructors and destructor

        /**

        * Two-phased constructor.

        */

        static CNssVASDBEventMonitor* NewL();

        /**

        * Destructor.

        */

        virtual ~CNssVASDBEventMonitor();

    public: // New functions

        /**

        * Request to start monitoring the VAS DB 

		* @since 2.0

        * @param void

        * @return void

        */

        void StartMonitoring();

		/**

        * Method that adds an observer to the observer list 

		* @since 2.0

        * @param aObserver to be added

        * @return none

        */

        void AddObserverL(MNssVASDatabaseObserver* aObserver);

		/**

        * Method that removes an observer from the observer list.

		* @since 2.0

        * @param aObserver to be removed

        * @return error code

        */

        TInt RemoveObserver(MNssVASDatabaseObserver* aObserver);

    public: // Functions from base classes

        /**

        * From CActive, called by RunL of RDBNotifier

		* @since 2.0

        * @param void

		* @return void

        */

        void RunL();

		/**

        * From CActive, cancel outstanding requests

		* @since 2.0

        * @param void

		* @return void

        */

        void DoCancel();

		/**

        * handling of addional events ( tag added, tag deleted, tag changed)

		* These events can be reported only when the events occur on the same 

		* thread as that of the observer (client monitoring the event).

		* @since 2.0

        * @param aEvent - VAS DB event type

		* @param aTag - tag on which the event occured

        * @return void

        */

		void HandleDatabaseEventL(CNssVASDBEvent::TVASDBEventType aEvent, CNssTag *aTag);

	private:

        /**

        * C++ constructor.

        */

        CNssVASDBEventMonitor();

        /**

        * EPOC constructor

        */

        void ConstructL();

		/**

        * Called by RunL() to create an event object and 

		* call HandleDatabaseEvent() for all observers

		* Handles Standard Symbian DBMS events

		* @since 2.0

        * @param aEvent - Symbian DBMS event

        * @return void

        */

        void HandleDatabaseEventL(RDbNotifier::TEvent aEvent);

    private:    // Data

		RDbs					iDbSession;

		RDbNamedDatabase		iDatabase;

        RDbNotifier				iNotifier;

		CArrayPtrFlat<MNssVASDatabaseObserver>* iObservers;

    };

#endif      // CVASDBEVENTMONITOR_H  

// End of File