/*

* Copyright (c) 2005-2009 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:

*

*/

/**

 @file

 @internalTechnology 

*/

#ifndef HWRMGENERICASYNCOBSERVER_H

#define HWRMGENERICASYNCOBSERVER_H

#include <e32base.h>

#include "HWRMClient.h"

/**

* Callback interface for async notification

*/

class MHWRMGenericAsyncObserver

    {

    public:

        /**

        * Notifies async response.

        *

        * @param aCommand Command for which the status value was obtained

        * @param aStatus Status value

        */

        virtual void AsyncRequestCompleted(TInt aCommand, TInt aStatusValue)=0;

    };

/**

* Active object wrapper for async HWRM client-server calls.

* Listens for status completion and notifies the callback.

* Also resubscribes the notification automatically.

*

*/

class CHWRMGenericAsyncObserver : public CActive

    {

    public:

        /**

        * This is a two-phase constructor method that is used to

        * create a new instance of CHWRMGenericAsyncObserver.

        * A newly created instance immediately starts listening to vibra status changes.

        *

        * @param aClient Reference to RHWRMClient instance that is used to (re)subscribe notification.

        * @param aCommand Command ID to be used in subscribing.

        * @param aInitialCommand Command ID to get initial value. 

        *         Initial value is not get if this parameter is negative.

        *         This initial command can only take one TInt parameter on slot 0,

        *         which is used to return the initial value.

        * @param aCallback Pointer to a callback instance. Can be NULL.

        * @return          A pointer to a new instance of the CHWRMGenericAsyncObserver class.

        */

        IMPORT_C static CHWRMGenericAsyncObserver* NewL(RHWRMClient& aClient, 

                                               TInt aCommand,

                                               TInt aInitialCommand,

                                               MHWRMGenericAsyncObserver* aCallback);

        /**

        * Destructor.

        */

        virtual ~CHWRMGenericAsyncObserver();

        /**

        * This method retrieves the most recently received status value.

        *

        * @return Integer indicating the latest status

        */

        TInt LatestStatus() const;

    protected:

        // From CActive

        void RunL();

        void DoCancel();

        // No need for RunError, as RunL will never leave

    private:

        /**

        * Constructor

        *

        * @param aClient Reference to RHWRMClient instance that is used to (re)subscribe notification.

        * @param aCommand Command ID to be used in subscribing.

        * @param aCallback Pointer to a callback instance. Must be non-NULL.

        */

        CHWRMGenericAsyncObserver(RHWRMClient& aClient, 

                                  TInt aCommand,

                                  MHWRMGenericAsyncObserver* aCallback);

        /**

        * By default Symbian 2nd phase constructor is private.

        *

        * @param aInitialCommand Command ID to get initial value. 

        *         Initial value is not get if this parameter is negative.

        *         This initial command can only take one TInt parameter on slot 0,

        *         which is used to return the initial value.

        */

        void ConstructL(TInt aInitialCommand);

        /*

        * Order notification

        */

        void OrderNotification();

    private:

        MHWRMGenericAsyncObserver* iCallback;   // Not owned by this class. Can be NULL.

        RHWRMClient& iClient;                   // HWRM Client, not owned

        TInt iCommand;                          // Stores command

        TInt iLatestStatus;                     // Stores status

    };

#endif      // HWRMGENERICASYNCOBSERVER_H

// End of File