/*

* Copyright (c) 2008-2009 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:  Definition of CListener class. Observers RProperty changes.

*

*/

#ifndef LISTENER_H

#define LISTENER_H

// SYSTEM INCLUDES

#include <aknappui.h> 

#include <aknViewAppUi.h>

#include <e32property.h>

#include <e32def.h>

// FORWARD DECLARATIONS

class MKeyObserver;

class MKeyAndStatusObserver;

// CLASS DECLARATION

/**

 *  Property listener class.

 *  Observes property keys for key values and status changes.

 *

 *  @code

 *  // Create new listener.

 *	CListener* listener = CListener::NewL( 

 *			 aPropertyCategory,

 *			 aKey

 *			 ); 

 *	 

 *	listener->RegisterNewClientForKeyValueL( aKeyObserver );

 *  @endcode

 *

 *  @lib common.lib

 *  @since -

 */

NONSHARABLE_CLASS( CListener )  : public CActive

    {

public: 

    /**

     * Factory method NewL

     * @param aPropertyCategory The property's category.   

     * @param aKey       		The P&S key to be watched. 

     * @return           		The new watcher object. 

     */

    static CListener* NewL( const TUid aPropertyCategory,

    			const TUint aKey );

    /**

     * Factory method NewLC

     * @param aPropertyCategory The property's category.   

     * @param aKey       		The P&S key to be watched. 

     * @return           		The new watcher object on the cleanupstack. 

      */

     static CListener* NewLC( const TUid aPropertyCategory,

     			const TUint aKey );

    /**

     * Destructor. Make public to clean it via CPropertyWatcher. 

     */

    virtual ~CListener();

public: // New functions

    /**

     * Returns observed key.

     * @return The key value.          		

     */

    TUint ObservedKey () const;

    /**

     * Returns observed category.

     * @return The category's uid.          		

     */

    TUid ObservedCategory () const;

    /**

     * Removes watcher client. 

     * @param aKeyObserver    Pointer to caller's adress.   

     */

    void RegisterNewClientForKeyValueL ( const MKeyObserver* aKeyObserver );

    /**

     * Adds new watcher client. Listens key and status changes.

     * @param aKeyAndStatusObserver    Pointer to caller's adress.   

     */

    void RegisterNewClientForKeyAndStatusL ( const MKeyAndStatusObserver* aKeyAndStatusObserver );

     /**

      * Removes watcher client. 

      * @param aKeyObserver    Pointer to caller's adress.   

      */

    void UnregisterKeyClient( const MKeyObserver* aKeyObserver );

     /**

      * Removes watcher client. 

      * @param aKeyAndStatusObserver    Pointer to caller's adress.   

      */

   	void UnregisterKeyAndStatusClient( 

    			const MKeyAndStatusObserver* aKeyAndStatusObserver );

private: // Construction and destruction.	

    /**

     * Constructor.

     * @param aPropertyCategory The property's category.   

     * @param aKey       		The P&S key to be watched. 

	 */

    			const TUint aKey ); 

   	/**

	 * Symbian 2nd phase constructor.

	 */

    void ConstructL();

private: // Functions from CActive

    /**

     *	Implements CActive

     */

    void RunL();

    /**

     *	Implements CActive

     *	@param aError the error returned

     *	@return error

     */

    TInt RunError( TInt aError );

    /**

     *	Implements CActive

     */

    void DoCancel();

private:

    /**

     *	Starts active object - listen key changes.

     */

	void StartListening();

	/**

     *	Send notifications to registered clients.

     *	@param aKeyValue - observed key's value.

     *	@return aStatus - reference to iStatus.

     */

	void SendNotificationsL( const TUint aKeyValue,

			TRequestStatus& aStatus ) const; 

private: // Data

    /*iArrayForKeyValue - all registered clients for value

     * owned by this class.*/

    RPointerArray<MKeyObserver> iArrayForKeyValue;    

	/*iArrayForKeyAndStatus - all registered clients for status

     * owned by this class*/

    RPointerArray<MKeyAndStatusObserver> iArrayForKeyAndStatus;  

    /*iPropertyCategory; - property's gategory.

     * owned by this class*/

    TUid iPropertyCategory;

	/*iKey - observed key, owned by this class*/

    TUint iKey;

	/*iProperty - owned by this class*/

    RProperty iProperty;

    };

#endif // LISTENER_H

// End of File.