/*

* Copyright (c) 2008 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:

* Subscribes properties from P&S

 *

*/

#ifndef XNPROPERTYSUBSCRIBER_H

#define XNPROPERTYSUBSCRIBER_H

// System includes

#include <e32base.h>

#include <e32property.h>

// Class declaration

/**

 * Observer for property change.

 */

class MXnPropertyChangeObserver

    {

public:

    /**

     * Property changed

     *

     * @since S60 5.1

     * @param aKey key value

     * @param aValue property value

     */

    virtual void PropertyChangedL( const TUint32 aKey, const TInt aValue ) = 0;

    };

/**

 * Subcribes property from P&S and listen property changes

 *

 * @ingroup group_xnlayoutengine

 * @lib xn3layoutengine.lib

 * @since Series 60 5.0

 */

NONSHARABLE_CLASS( CXnPropertySubscriber ) : public CActive

    {

public:

    /**

     * Cancel and destroy

     */

    ~CXnPropertySubscriber();

    /**

    * Two-phased constructor.

    *

    * @param aUid P&S property category

    * @param aKey P&S property key

    * @param aObserver Given property change observer

    */

    static CXnPropertySubscriber* NewL(

        const TUid aUid,

        const TUint32 aKey,

        MXnPropertyChangeObserver& aObserver );

    /**

    * Two-phased constructor.

    *

    * @param aUid P&S property category

    * @param aKey P&S property key

    * @param aObserver Given property change observer

    */

    static CXnPropertySubscriber* NewLC(

        const TUid aUid,

        const TUint32 aKey,

        MXnPropertyChangeObserver& aObserver );

private:

    /**

     * C++ constructor

     */

    CXnPropertySubscriber(

        MXnPropertyChangeObserver& aObserver,

        const TUint32 aKey );

    /**

     * Second-phase constructor

     */

    void ConstructL( const TUid aUid, const TUint32 aKey );

private:

    /**

     * Handles an active object's request completion event.

     * 

     * @see CActive::RunL

     */

    void RunL();

    /**

     * Implements cancellation of an outstanding request.

     * 

     * @see CActive::DoCancel

     */

    void DoCancel();

    /**

     * RunError

     * 

     * @see CActive::RunError

     */

    TInt RunError(TInt aError);

private:

    // Data

    /**

     * Observer for property changes.

     * Not own

     */

    MXnPropertyChangeObserver& iPropertyChangeObserver;

    /**

     * Property to listen

     */

    RProperty iProperty;

    /**

     * P&S property key

     */

    TUint32 iKey;

    };

#endif