/*

* Copyright (c) 2007 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:  Channel change notifications queue implementation

*

*/

#ifndef SENSRVCHANNELCHANGEQUEUE_H

#define SENSRVCHANNELCHANGEQUEUE_H

#include <e32base.h>

#include "sensrvchannelinfo.h"

/**

 * Channel change notifications queue. 

 *

 * @since S60 5.0

 */

class CSensrvChannelChangeQueue : public CBase

    {

    public:

        /**

        * Linkable data about channel change notification

        */

        class TChannelChangeNotification

            {

            public:

                TChannelChangeNotification()

                    {

                    }

                /**

                * Link item for queueing channel change notifications

                */

                TSglQueLink iLink;

                /**

                * Channel info

                */

                TSensrvChannelInfo iChannelInfo;

                /**

                * Change type

                */

                TSensrvChannelChangeType iChangeType;

            };

        /**

        * Two phase constructor.       

        */

        static CSensrvChannelChangeQueue* NewL();

        /**

        * Destructor.

        */

        virtual ~CSensrvChannelChangeQueue();

        /**

        * Creates new TChannelChangeNotification and adds it to the the queue.

        *

        * @since S60 5.0

        * @param aChannelInfo The channel info related to change

        * @param aChangeType Type of the change

        * @return Symbian OS standard error code.

        */

        TInt Append( const TSensrvChannelInfo& aChannelInfo,

                     TSensrvChannelChangeType aChangeType );

        /**

        * Gets pointer to first change notification from queue.

        *

        * @since S60 5.0

        * @return First change notification in queue, or NULL if empty.

        */

        TChannelChangeNotification* First();

        /**

        * Removes and deletes first change notification from queue,

        * if queue has any notifications.

        *

        * @since S60 5.0

        */

        void RemoveFirst();

        /**

        * Removes and deletes all queued change notifications.

        *

        * @since S60 5.0

        */

        void RemoveAll();

        /**

        * Checks if queue is empty

        *

        * @since S60 5.0

        * @return ETrue if queue is empty.

        */

        inline TBool IsEmpty() {return iChangesList.IsEmpty(); };

    private:

        /**

        * C++ constructor

        */

        CSensrvChannelChangeQueue();

        /**

        * 2nd phase of construction

        *

        * @since S60 5.0

        */

        void ConstructL();            

    private:

        /**

        * Holds queued properties.

        * Queued objects are owned.

        */

        TSglQue<TChannelChangeNotification> iChangesList;

        /**

        * Iterator for property queue

        */        

        TSglQueIter<TChannelChangeNotification> iChangesListIter;

    };

#endif // SENSRVCHANNELCHANGEQUEUE_H