1 /*

     2 * Copyright (c) 2006 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:   Notifies observers of external changes to the calendar database

    15 *

    16 */

    17 

    18 

    19 #ifndef __CALENDBCHANGENOTIFIER_H

    20 #define __CALENDBCHANGENOTIFIER_H

    21 

    22 //  INCLUDES

    23 #include <e32base.h>

    24 

    25 #include <calchangecallback.h>      //MCalChangeCallBack

    26 

    27 // FORWARD DECLARATIONS

    28 class CCalSession;                  //Calendar session

    29 class CCalenGlobalData;             //Calendar global data

    30 

    31 // CLASS DECLARATION

    32 

    33 /**

    34 * Observer class for database changes.  Forwards callback from 

    35 * MCalChangeCallBack2

    36 */

    37 class MCalenDBChangeObserver

    38     {

    39     public:

    40         virtual void HandleDBChangeL() = 0;

    41     };

    42 

    43 /**

    44 *  CCalenDbChangeNotifier buffers notifications from MCalChangeCallBack2 and 

    45 *  only notifies its observers after a set period has elapsed.  This prevents

    46 *  Calendar views refreshing more often than necessary during a sync operation

    47 */

    48 NONSHARABLE_CLASS(CCalenDbChangeNotifier) : public CActive,

    49                                                                   public MCalChangeCallBack2

    50     {

    51     public:  // Constructors and destructor

    52         /**

    53         * Constructor.

    54         * @param aGlobalData global data reference

    55         * @return a pointer to the new CCalenDbChangeNotifier instance

    56         */

    57         static CCalenDbChangeNotifier* NewL( CCalenGlobalData& aGlobalData );

    58 

    59        /**

    60         * Destructor.

    61         */

    62         ~CCalenDbChangeNotifier();

    63         

    64     public:

    65         /**

    66         * Allow CCalenViews to register for database change notifications

    67         * @param aDBObserver Observer to register

    68         */

    69         void RegisterObserverL( MCalenDBChangeObserver& aDBObserver );

    70         

    71         /**

    72         * Allow CCalenViews to deregister for database change notifications

    73         * @param aDBObserver Observer to deregister

    74         */

    75         void DeRegisterObserverL( MCalenDBChangeObserver& aDBObserver );

    76         

    77         /**

    78         * Returns the time of the last call to MCalChangeCallBack2::CalChangeNotification

    79         * This is not necessarily the same time as the last notification issued by 

    80         * this class

    81         * @return Time of the last database modification as TTime

    82         */

    83         TTime LastDBModificationTime() const;

    84         

    85     public: 

    86         /**

    87         * From MCalChangeCallBack2

    88         * Called when the calendar database is changed through another

    89         * CCalSession

    90         * @param aChangeItems array of database items changed 

    91         */

    92         void CalChangeNotification( RArray<TCalChangeEntry>& aChangeItems );

    93 

    94     private:

    95         /**

    96         * C++ default constructor.

    97         * @param aGlobalData global data reference

    98         */

    99         CCalenDbChangeNotifier( CCalenGlobalData& aGlobalData );

   100 

   101         /**

   102         * By default Symbian 2nd phase constructor is private.

   103         * Performs any construction which may leave

   104         */

   105         void ConstructL();

   106 

   107         /**

   108         * From CActive

   109         * Called when outstanding asynchronous request completes

   110         * This will be called when iNotificationTimer either completes

   111         * or is cancelled

   112         */

   113         void RunL();

   114         

   115         /**

   116         * From CActive

   117         * Called by the active scheduler if RunL leaves

   118         * Ensures we are ready to receive the next database event

   119         * @param aError System wide error code

   120         */

   121         TInt RunError( TInt aError );

   122 

   123         /**

   124         * From CActive

   125         * Implements cancellation of outstanding asynchronous requests

   126         * Cancels iNotificationTimer if started

   127         */

   128         void DoCancel();

   129 

   130     private:    // Data

   131         CCalenGlobalData& iGlobalData;

   132         

   133         //Database change observer filter

   134         CCalChangeNotificationFilter* iCalChangeFilter;      

   135         

   136         //Observer array

   137         RPointerArray<MCalenDBChangeObserver> iDBObservers;

   138         

   139         //Timer to limit the amount of notifications issued by this class

   140         RTimer iNotificationTimer;

   141         

   142         //The time of the last received notification

   143         TTime iLastDbChangeNotification;

   144         

   145         //Flag to restart the timer after cancelling last tiemr request

   146         TBool iRestartTimer;

   147     };

   148 

   149 #endif      // __CALENDBCHANGENOTIFIER_H

   150 

   151 // End of File