/*

* Copyright (c) 2004 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:  Publish & Subscribe property change observer

*

*/

#ifndef CIMPSPROPERTYOBSERVER_H

#define CIMPSPROPERTYOBSERVER_H

//  INCLUDES

#include <e32base.h>        // CActive

#include <e32property.h>    // RProperty

#include "MIMPSPropertyNotificationObserver.h"

// FORWARD DECLARATIONS

class MIMPSPropertyNotificationObserver;

// CLASS DECLARATION

/**

*  Implementation of the Publish & Subscribe property change observer

*

*  @lib MGXMediaFileAPI.lib

*  @since 2.6

*/

NONSHARABLE_CLASS( CIMPSPropertyObserver ) : public CActive

    {

public:  // Constructors and destructor

    /**

    * Two-phased constructor.

    * @param aObserver Observer to be informed when observed property changes

    */

    static CIMPSPropertyObserver* NewL( MIMPSPropertyNotificationObserver& aObserver );

    /**

    * Destructor.

    */

    virtual ~CIMPSPropertyObserver();

public:     // New functions

    /**

    * Starts observing the given key for any changes

    * Notifies the observer when the property changes

    * @since 2.6

    * @param aCategory, Category of the observed property

    * @param aKey, Observed property

    */

    void ObservePropertyChangeL( TUid aCategory, TUint aKey );

    /**

    * Stops observing the key given with call ObserverPropertyChangeL

    */

    void CancelObserve( );

    /**

    * Gets the uid this observer is observing

    * @return the category

    */

    TUid Category();

    /**

    * Gets the uid this observer is observing

    * @return the key

    */

    TUint Key();

protected:  // Functions from base classes

    /**

    * From CActive

    */

    void RunL();

    /**

    * From CActive

    */

    void DoCancel();

private:

    /**

    * C++ default constructor.

    */

    CIMPSPropertyObserver( MIMPSPropertyNotificationObserver& aObserver );

    /**

    * Symbian 2nd phase constructor..

    */

    void ConstructL();

private:    // Data

    // Owns: Observed property

    RProperty iProperty;

    // Observer to be informed when property changes

    MIMPSPropertyNotificationObserver& iObserver;

    // the category this observer is attached to

    TUid iCategory;

    // the key this observer is attached to

    TUint iKey;

    };

#endif      // CIMPSPROPERTYOBSERVER_H

// End of File