1 /*

     2 * Copyright (c) 2007 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 the License "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: 

    15 *

    16 */

    17 

    18 

    19 #ifndef SYSTEMOBSERVER_H

    20 #define SYSTEMOBSERVER_H

    21 

    22 // INCLUDES

    23 #include <e32base.h>

    24 #include <npscript.h>

    25 

    26 // FORWARD DECLARATIONS

    27 

    28 // CONSTANTS

    29 

    30 // State enum and member variable

    31 

    32 // CLASS DECLARATIONS

    33 

    34 /**

    35  * MSystemInfoObserverClient is an interface to whatever data is being

    36  * observed (RProperty, int, string, etc).

    37  * @lib npSystemInfoPlugin.lib

    38  * @since S60 v3.2

    39  */

    40 class MSystemInfoObserverClient

    41     {

    42 public:

    43     virtual void SubscribeL( TInt aId, TRequestStatus& aStatus ) = 0;

    44     virtual void UpdateL( TInt aId ) = 0;

    45     virtual void Cancel( TInt aId ) = 0;

    46     virtual void Close( TInt aId ) = 0;

    47 /*

    48  * Outline of use for a publish and subscribe variable

    49  * #include <e32property.h>

    50  * #include <hwrmpowerstatesdkpskeys.h>

    51  * RProperty iProperty;

    52  * iProperty.Attach( KPSUidHWRMPowerState, KHWRMBatteryLevel );

    53  * SubscribeL => iProperty.Subscribe( status );

    54  * UpdateL => iProperty.Get( value );

    55  * Cancel => iProperty.Cancel();

    56  * Close => iProperty.Close();

    57  * The ID parameter is there so that a class can contain

    58  * multiple observers and differentiate them in these methods by ID.

    59  * You can also use it for state in a state machine.

    60  */

    61     };

    62 

    63 /**

    64 *  CSystemInfoObserver.

    65 *  Active class for monitoring variables.

    66 *  @lib npSystemInfoPlugin.lib

    67 *  @since S60 v3.2

    68 */

    69 NONSHARABLE_CLASS(CSystemInfoObserver) : public CActive

    70     {

    71 public:

    72     /**

    73      * Two-phased constructor.

    74      */

    75     static CSystemInfoObserver* NewL( MSystemInfoObserverClient* aClient, TInt aId );

    76 

    77     /**

    78      * Destructor.

    79      */

    80     virtual ~CSystemInfoObserver();

    81 

    82 private:

    83     /**

    84      * C++ default constructor.

    85      */

    86     CSystemInfoObserver( MSystemInfoObserverClient* aClient, TInt aId );

    87 

    88     /**

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

    90      * @param none

    91      * @return void

    92      */

    93     void ConstructL();

    94 

    95 public:

    96     /**

    97      * Request observed status change notification

    98      * @since 3.2

    99      * @param none

   100      * @return void

   101      */

   102     void RequestNotificationL();

   103 

   104 protected:    // CActive

   105     /**

   106      * Implements cancellation of an outstanding request.

   107      * @param none

   108      * @return void

   109      */

   110     void DoCancel();

   111 

   112     /**

   113      * Handles an active object’s request completion event.

   114      * @param none

   115      * @return void

   116      */

   117     void RunL();

   118 

   119     /**

   120      * Handles an active object’s error

   121      * @param error

   122      * @return void

   123      */

   124     TInt RunError(TInt aError);

   125 

   126 private:

   127     MSystemInfoObserverClient* iClient;

   128     TInt iId;

   129     };

   130 

   131 #endif      // SYSTEMOBSERVER_H

   132 

   133 // End of File