1 /*

     2 * Copyright (c) 2004-2005 Nokia Corporation and/or its subsidiary(-ies). 

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:  Publish & Subscribe property change observer

    15 *

    16 */

    17 

    18 

    19 #ifndef CCAPROPERTYOBSERVER_H

    20 #define CCAPROPERTYOBSERVER_H

    21 

    22 //  INCLUDES

    23 #include <e32base.h>        // CActive

    24 #include <e32property.h>    // RProperty

    25 

    26 #include "MCAPropertyNotificationObserver.h"

    27 

    28 

    29 // CLASS DECLARATION

    30 

    31 /**

    32 *  Implementation of the Publish & Subscribe property change observer

    33 *

    34 *  @lib MGXMediaFileAPI.lib

    35 *  @since 2.6

    36 */

    37 NONSHARABLE_CLASS( CCAPropertyObserver ) : public CActive

    38     {

    39 public:  // Constructors and destructor

    40 

    41     /**

    42     * Two-phased constructor.

    43     * @param aObserver Observer to be informed when observed

    44     *                  property changes

    45     */

    46     static CCAPropertyObserver* NewL(

    47         MCAPropertyNotificationObserver& aObserver );

    48 

    49     /**

    50     * Destructor.

    51     */

    52     virtual ~CCAPropertyObserver();

    53 

    54 public:     // New functions

    55 

    56     /**

    57     * Starts observing the given key for any changes

    58     * Notifies the observer when the property changes

    59     * @since 2.6

    60     * @param aCategory, Category of the observed property

    61     * @param aKey, Observed property

    62     */

    63     void ObservePropertyChangeL( TUid aCategory, TUint aKey );

    64 

    65     /**

    66     * Stops observing the key given with call ObserverPropertyChangeL

    67     */

    68     void CancelObserve( );

    69 

    70     /**

    71     * Gets the uid this observer is observing

    72     * @return the category

    73     */

    74     TUid Category();

    75 

    76     /**

    77     * Gets the uid this observer is observing

    78     * @return the key

    79     */

    80     TUint Key();

    81 

    82 

    83 protected:  // Functions from base classes

    84 

    85     /**

    86     * From CActive

    87     */

    88     void RunL();

    89 

    90     /**

    91     * From CActive

    92     */

    93     void DoCancel();

    94 

    95 private:

    96 

    97     /**

    98     * C++ default constructor.

    99     */

   100     CCAPropertyObserver( MCAPropertyNotificationObserver& aObserver );

   101 

   102 

   103 private:    // Data

   104 

   105     // Owns: Observed property

   106     RProperty iProperty;

   107 

   108     // Observer to be informed when property changes

   109     MCAPropertyNotificationObserver& iObserver;

   110 

   111     // the category this observer is attached to

   112     TUid iCategory;

   113     // the key this observer is attached to

   114     TUint iKey;

   115 

   116     };

   117 

   118 #endif      // CCAPROPERTYOBSERVER_H

   119 

   120 // End of File