/*

* Copyright (c) 2007-2009 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:      An abstract proxy for a rendering session observer

*

*/

#ifndef UPNPABSTRACTRENDERINGSESSIONOBSERVER_H

#define UPNPABSTRACTRENDERINGSESSIONOBSERVER_H

//  INCLUDES

#include <e32base.h>

#include "upnpavrenderingsessionobserver.h" // base class

// FORWARD DECLARATIONS

class MUPnPAVRenderingSession;

// CLASS DECLARATION

/**

* An abstract class for implementing a rendering session observer.

* This class is purposed as a base class for imnplementing a

* rendering session observer. There are 2 main use cases:

* 1. reducing implementation code so that the actual observer will

*    only need to write the observer methods that are really used.

* 2. implementing an observer proxy that will attach itself to a session

*    and just handle some of the callbacks and forward a majority of the

*    callbacks the original session observer.

*

* @lib upnpavcontrollerhelper.lib

* @since S60 3.2

*/

class CUPnPAbstractRenderingSessionObserver

    : public CBase

    , public MUPnPAVRenderingSessionObserver

    {

public: // construction/destruction

    /**

     * default constructor.

     */

    IMPORT_C CUPnPAbstractRenderingSessionObserver();

    /**

     * destructor

     */

    IMPORT_C virtual ~CUPnPAbstractRenderingSessionObserver();

public: // the abstract observer interface

    /**

     * Sets the host session for the observer. This is the session where

     * the observer will register for callbacks. If the session already

     * has an observer, it will become the proxy observer. The default

     * implementatin for all observer methods is to forward the method to

     * the observer, if it exists.

     *

     * @since S60 3.2

     * @param aHostSession, rendering session

     */

    IMPORT_C void SetSession( MUPnPAVRenderingSession& aHostSession );

    /**

     * Enables receiving callbacks. When enabled, the abstract observer

     * registers to the given session and thus starts receiving callbacks.

     * Note that only those callbacks that are overwritten in the derived

     * class will actually provide some value. Other will be either processed

     * in an empty method, or forwarded to the observer that previously was

     * registered as an observer (proxy mode)

     *

     * @since S60 3.2

     */

    IMPORT_C void EnableSessionObserver();

    /**

     * Disables receiving session callbacks. The observer interface is

     * deregistered, and if before observer registration there was an 

     * original observer interface (proxy mode) the original observer

     * is restored.

     *

     * @since S60 3.2

     */

    IMPORT_C void DisableSessionObserver();

    /**

     * Returns true if the observer is active (registered for events)

     *

     * @since S60 3.2

     */

    IMPORT_C TBool IsSessionObserverEnabled();

public: // MUPnPAVRenderingSessionObserver

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void VolumeResult( TInt aError, TInt aVolumeLevel,

        TBool aActionResponse );

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void MuteResult( TInt aError, TBool aMute,

        TBool aActionResponse );

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void InteractOperationComplete( TInt aError,

        TUPnPAVInteractOperation aOperation );

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void PositionInfoResult( TInt aError,

        const TDesC8& aTrackPosition, const TDesC8& aTrackLength );

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void SetURIResult( TInt aError );

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void SetNextURIResult( TInt aError );

    /**

     * see MUPnPAVRenderingSessionObserver

     */

    void MediaRendererDisappeared(

        TUPnPDeviceDisconnectedReason aReason );

private: // members

    // the host rendering session. Note: NOT OWNED!

    MUPnPAVRenderingSession* iObservedSession;

    // The proxy observer. Note: NOT OWNED!

    MUPnPAVRenderingSessionObserver* iProxyObserver;

    // if observer is enabled

    TBool iObserverEnabled;

    };

#endif  // UPNPABSTRACTRENDERINGSESSIONOBSERVER_H

// End of File