/*

* 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:  

*

*/

#ifndef DEVENCSTARTERPROPERTYOBSERVER_H

#define DEVENCSTARTERPROPERTYOBSERVER_H

// INCLUDES

#include <e32base.h>

#include <e32property.h>

// CLASS DECLARATION

/**

 * MDevEncStarterPropertyChangeObserver

 * Abstract interface for handling property change events.

 **/

class MDevEncStarterPropertyChangeObserver

    {

    public:

        /**

         * This is a callback function which is called when a property value is changed.

         * @param aObserver a refference to the observer interface implementer

         * @param aCategory UID of Publish And Subscribe category

         * @param aKey subkey to specify the category event; to be used with Publish And Subscribe

         * @param aValue the new value

         * Event enumerations and uid:s of Publish And Subscribe can be found from PSVariables.h

         **/

        virtual void HandlePropertyChangeL( const TUid& aCategory,

                                            const TUint aKey,

                                            const TInt aValue ) = 0;

        /**

         * This is a callback function which is called when a P&S components returns an error

         * @param aCategory UID of Publish And Subscribe category

         * @param aKey subkey to specify the category event

         * @param aError an error code

         **/

        virtual void HandlePropertyChangeErrorL( const TUid& aCategory,

                                                 const TUint aKey,

                                                 TInt aError ) = 0;

    };

// INCLUDES

// CONSTANTS

// CLASS DECLARATION

/**

 * Observer class that observes changes of Property values and propogates them further.

 * The class defines a handle to a property, a single data value representing

 * an item of state information.

 *

 **/

class CDevEncStarterPropertyObserver : public CActive

	{

public:  // Constructors and destructor

    /**

     * Two-phased constructor.

     * @param aObserver a reference to the observer interface implementer

     * @param aCategory UID of Publish And Subscribe category

     * @param aKey subkey to specify the category event; to be used with Publish And Subscribe

     * Event enumerations and uid:s of Publish And Subscribe can be found from PSVariables.h

     **/

    static CDevEncStarterPropertyObserver* NewL( MDevEncStarterPropertyChangeObserver& aObserver,

                                            const TUid& aCategory,

                                            const TUint aKey );

    /**

     * Destructor.

     **/

    ~CDevEncStarterPropertyObserver();

    /**

     * Updates a value reference in correspondence with the current Property value

     * @param handle to a value which will be updated

     * @return KErrNone if operation was successful

     **/

	void GetValue( TInt& aValue ) const;

 private:

    /**

     * C++ default constructor overload.

     * Two-phased constructor.

     * @param aObserver a reference to the observer interface implementer

     * @param aCategory UID of Publish And Subscribe category

     * @param aKey subkey to specify the category event; to be used with Publish And Subscribe

     * Event enumerations and uid:s of Publish And Subscribe can be found from PSVariables.h

     **/

	CDevEncStarterPropertyObserver( MDevEncStarterPropertyChangeObserver& aObserver,

	                           const TUid& aCategory,

	                           const TUint aKey );

    /**

     * By default Symbian 2nd phase constructor is private.

     **/

    void ConstructL();

 protected:  // Functions from base classes

    /**

     * From CActive

     * Handles an active object’s request completion event

     **/

    void RunL();

    /**

     * From CActive,

     * Cancels and outstanding request

     **/

    void DoCancel();

 private:  // Data

 	// Value of a subscribed category property

 	TInt iValue;

    // handle to Publish And Subscribe component

    RProperty iProperty;

    // Observer to be notified when particular Property value has changed

    MDevEncStarterPropertyChangeObserver& iObserver;

    // UID of Publish And Subscribe category

    TUid iCategory;

    // subkey to be used with Publish And Subscribe

    TUint iKey;

	};

#endif  // CPROPERTYOBSERVER_H

// End of File