/*

* 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:  Condition listener call-back interface

*

*/

#ifndef SENSRVCHANNELCONDITIONLISTENER_H

#define SENSRVCHANNELCONDITIONLISTENER_H

#include <e32base.h>

#include <sensrvchannelconditionset.h>

#include <sensrvtypes.h>

/**

* Condition listener callback interface to indicate when a ConditionSet has been met.

* 

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

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

* it in CSensrvChannel::StartConditionListeningL().

* 

* @see CSensrvChannel::StartConditionListeningL()

* @see CSensrvChannel::StopConditionListening()

* @see CSensrvChannel::AddConditionL()

* @see CSensrvChannel::RemoveConditionL()

* @lib sensrvclient.lib

* @since S60 5.0

*/

class MSensrvChannelConditionListener

    {

    public:

    /**

    * Callback implemented by a client so that they can be notified when a channel ConditionSet

    * is met. If a client wants to use same ConditionSet after receiving this notification, the

    * client must add ConditionSet again to the channel object. If the ConditionSet is no longer

    * required the client can destroy it. 

    * 

    * If the ConditionSet contains more than one condition, it is not known which of the individual

    * conditions in the set were met.

    * 

    * 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  aChannelConditionSet Channel ConditionSet that is met

    * @param  aValue Channel data value that met the condition

    * @see CSensrvChannel::GetData() for example on how to retrive data from aValue

    */  

    virtual void ConditionMet( CSensrvChannel& aChannel, 

                               CSensrvChannelConditionSet& aChannelConditionSet, 

                               TDesC8& aValue ) = 0;

    /**

    * Callback implemented by a client so that they can be notified when condition 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 condition matches 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 ConditionError ( CSensrvChannel& aChannel, 

                                  TSensrvErrorSeverity aError ) = 0;

	  /** 

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

    * without breaking binary compatibility.

    * 

    * @since S60 5.0

    * @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.

    * @leave  One of the system-wide error codes

    */

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

    };

#endif //SENSRVCHANNELCONDITIONLISTENER_H

// End of File