/*

 * Copyright (c) 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: Telephony Multimedia Service

 *

 */

#ifndef TMS_STREAM_OBSRVR_H

#define TMS_STREAM_OBSRVR_H

// Include files

#include <tms.h>

namespace TMS {

// Forward declarations

class TMSStream;

/**

 * TMSStreamObserver class

 *

 * This class provides callback mechanism for TMSStream listeners.

 *

 * Client class that is interested in observing stream notifications has to

 * inherit from TMSStreamObserver class and register itself with the TMSStream.

 * Functions declared in this class are called when events occur in TMSStream.

 *

 * The client must not do any blocking, or perform any CPU-intensive operations

 * in the callback methods. It is recommended that the client saves event data,

 * returns from this function immediately, and if necessary, responds to

 * the event in asynchronous way.

 *

 * Usage:

 * <code>

 * // Register as an observer to the uplink stream

 * iUplinkStream->AddObserver(*this, NULL);

 * ...

 * // Unregister (optional)

 * iUplinkStream->RemoveObserver(*this);

 * ...

 * </code>

 *

 * @lib tmsapi.lib

 *

 */

class TMSStreamObserver

    {

public:

    /**

     * Signal stream event.

     *

     * This function is called when a stream event occurs.

     *      (1) TMS_EVENT_TYPE_STATE_CHANGED.

     *

     *

     * @param  stream

     *      Pointer to the object that is being signaled.

     *

     * @param  event

     *      Event descriptor.

     *

     */

    virtual void TMSStreamEvent(TMSStream* stream, TMSSignalEvent event) = 0;

    };

} //namespace TMS

#endif // TMS_STREAM_OBSRVR_H

// End of file