/*

* Copyright (c) 2002-2007 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:  MNssContextManager interface provides context processing methods for 

*				 the client. The client  gets an instance of the context manager 

*				 from the vas db manager. The vas db manager owns the context manager 

*				 and is responsible for deleting the context manager. Clients should not 

*				 directly delete the context manager. The context manager is simply a 

*				 colllection of utility methods  that are pure virtuals. These methods are implemented

*				 internal to VAS, and thus transparent to the client.

*

*/

#ifndef MNSSCONTEXTMGR_H

#define MNSSCONTEXTMGR_H

#include <e32std.h>

#include "nssvascoreconstant.h"

//FORWARD DECLARATIONS

class MNssGetContextClient;

class MNssDeleteContextClient;

class MNssSaveContextClient;

class MNssContext;

// CLASS DECLARATIONS

/**

*  MNssContextMgr is the public interface class for context management.

*  It provides methods for context creation, saving context into the

*  VAS database, retriving contexts from VAS database, and deletion of 

*  context from the VAS database. A context manager cannot be instantiated

*  directly but needs to be got from the VAS DB manager.

*  @lib NssVASApi.lib

*  @since 2.8

*  

*/

class MNssContextMgr

   {

public:

    /**

    * Create a new empty context

    * @since 2.0

    * @param 

    * @return a reference to a new context object.

    */

    virtual MNssContext* CreateContextL()=0;

    /**

    * GetContext is called to retrieve a context from the VAS DB. 

    * This method is asynchronous. A call back will be made to 

    * either GetContextCompleted() or GetContextFailed() as

    * defined in the MNssGetContextClient interface. It also returns an

    * error code validating success of call to VAS DB.

    * @since 2.0

    * @param aContextClient - call back address

    * @param aName          - name of context to retreive

    * @return - syncronous error code from function return

    */    

    virtual TInt GetContext( MNssGetContextClient* aContextClient, const TDesC& aName ) = 0;

    /**

    * GetContextList is called to retrieve a context list from the VAS DB. 

    * This method is asynchronous. A call back will be made to 

    * either GetContextListCompleted() or GetContextFailed() as

    * defined in the MNssGetContextClient interface. It also returns an

    * error code validating success of call to VAS DB.

    * @since 2.0

    * @param aContextClient - call back address 

    * @param  

    * @return - syncronous error code from function return

    */    

    virtual TInt GetContextList( MNssGetContextClient* aContextClient ) = 0;

    /**

    * DeleteContext is called to remove a context from the VAS DB. 

    * This method is asynchronous. A call back will be made to 

    * either DeleteContextCompleted() or DeleteContextFailed() as

    * defined in the MNssDeleteContextClient interface. It also returns an

    * error code validating success of call to VAS DB.

    * @since 2.0

    * @param aContextClient - call back address

    * @param aContext       - context object to delete

    * @return syncronous error code from function return

    */     

    virtual TInt DeleteContext( MNssDeleteContextClient* aContextClient,

                                MNssContext* aContext ) = 0;

    /**

    * SaveContext is called to store a context to the VAS DB. 

    * This method is asynchronous. A call back will be made to 

    * either SaveContextCompleted() or SaveContextFailed() as

    * defined in the MNssSaveContextClient interface. It also returns an

    * error code validating success of call to VAS DB.

    * @since 2.0

    * @param aContextClient - call back address

    * @param aContext       - context object to save

    * @return - syncronous error code from function return

    */

    virtual TInt SaveContext( MNssSaveContextClient* aContextClient, MNssContext* aContext ) = 0;

    /**

    * SaveClientData is called to save client-specific data about the context.

    * This method is asynchronous. A call back will be made to either

    * SaveContextCompleted or SaveContextFailed() as defined in the

    * MNssSaveContextClient interface. It also returns an error code validating

    * success of call to VAS DB.

    * @since 2.8

    * @param aContextClient - call back address.

    * @param aContext       - the client data of this context will be updated.

    * @param aClientData    - buffer of serialized client data, at most 100 bytes.

    */

    virtual TInt SaveClientData( MNssContext* aContext ) = 0;

    /**

    * Cancel get context / get context list / get global contexts 

    * @since 3.2

    * @param none

    * @return none

    */     

    virtual void CancelGetContext() = 0;

    };

#endif // MNSSCONTEXTMGR_H