/*

* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

* which accompanies this distribution, and is available

* at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Property listener callback interface

*

*/

#ifndef SENSRVPROPERTYLISTENER_H

#define SENSRVPROPERTYLISTENER_H

#include <e32base.h>

#include <sensrvtypes.h>

#include <sensrvproperty.h>

#include <sensrvchannel.h>

// CLASS DECLARATIONS

/**

* Property listener callback interface to indicate when a property has changed or when

* clients access to setting properties has changed.

* 

* This class is for use with the CSensrvChannel::SetPropertyListenerL() method. Clients wishing

* to use property listening must inherit from this class and provide a reference to an instance

* of it in CSensrvChannel::SetPropertyListenerL().

* 

* @see CSensrvChannel::SetPropertyListenerL()

* @lib sensrvclient.lib

* @since S60 5.0

*/

class MSensrvPropertyListener

    {

    public:

    /**

    * Callback implemented by a client so that they can be notified when the value of a

    * property has changed. The client that set the property will not be notified.

    * 

    * Clients providing an implementation for this callback must ensure that the operation does

    * not leave. If a leave does occur then the behaviour is undefined.

    * 

    * @since S60 5.0

    * @param  aChannel Channel associated with the listener

    * @param  aChangedProperty The property that has changed

    */  

    virtual void PropertyChanged( CSensrvChannel& aChannel, 

                                  const TSensrvProperty& aChangedProperty ) = 0;

    /**

    * Callback implemented by a client so that they can be notified when property listening

    * has failed. If the error is fatal the channel will be closed, the sensor server session

    * has been terminated and the channel object is no longer useable. If the error is minor,

    * some property changes have potentially been missed, however listening is still active.

    * 

    * Clients providing an implementation for this callback must ensure that the operation does

    * not leave. If a leave does occur then the behaviour is undefined.

    * 

    * @since S60 5.0

    * @param  aChannel Channel associated with the listener

    * @param  aError The error severity

    */

    virtual void PropertyError( CSensrvChannel& aChannel, 

                                TSensrvErrorSeverity aError ) = 0;

    /**

    * Callback implemented by a client so that they can be notified when the clients access for 

    * setting properties has changed.

    * 

    * Clients providing an implementation for this callback must ensure that the operation does

    * not leave. If a leave does occur then the behaviour is undefined.

    * 

    * @since S60 5.0

    * @param  aIndication Indication of the clients access for setting of properties  

    */

    virtual void SetPropertySuccessIndicationChanged( 

                 TSetPropertySuccessIndicator aIndication ) = 0;

    /** 

    * Callback to future proof this API so that additional callbacks can be added in the future 

    * without breaking binary compatibility.

    * 

    * @param  aInterfaceUid Identifier for the interface to be retrieved

    * @param  aInterface A reference to a pointer for the specified interface. Implementation sets

    * aInterface to a valid pointer if the M-class identified by aInterfaceUid is supported, otherwise

    * it is set to NULL on exit.

    * 

    * @since S60 5.0

    * @leave  One of the system-wide error codes

    */

	virtual void GetPropertyListenerInterfaceL( TUid aInterfaceUid, TAny*& aInterface ) = 0;

    };

#endif //SENSRVPROPERTYLISTENER_H

// End of File