/*

* Copyright (c) 2006 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:   ?Description

*

*/

#ifndef M_NCD_LOAD_NODE_OPERATION_OBSERVER_H

#define M_NCD_LOAD_NODE_OPERATION_OBSERVER_H

#include <e32cmn.h>

#include "catalogsarray.h"

class MNcdLoadNodeOperation;

class MNcdQuery;

class MNcdNode;

/**

 *  Observer interface for node load operations

 *

 *  Node load operation users should implement this interface to be able to

 *  receive callbacks.

 *

 *  The observer can show progress via either the progress variable or by

 *  loaded nodes count / total count of nodes to load or both.

 *

 *  

 *  @see MNcdLoadNodeOperation

 */

class MNcdLoadNodeOperationObserver

    {

public:

    /**

     * Called when nodes have been updated. This may be called numerous 

     * times during one operation. The nodes can now be queried for name,

     * description etc. information.

     *

     * 

     * @param aOperation Reference to the operation reporting the updates.

     *  Uncounted; if the observer implementation wants to save

     *  the operation pointer for later use, it must call AddRef() for

     *  it first, and Release() after use.

     * @param aNodes Array of pointers to updated nodes. The references

     *  in the array are uncounted; if the observer implementation wants to

     *  save a node pointer for later use, it must call AddRef() for it first,

     *  and Relese() after is no longer needed.

     */

    virtual void NodesUpdated( MNcdLoadNodeOperation& aOperation,

                               RCatalogsArray< MNcdNode >& aNodes ) = 0;

    /**

     * Called when a query has been received for an operation. The query

     * object can be obtained from the operation object with

     * MNcdOperation::QueryL().

     *

     * @note Querys need to be completed with MNcdOperation::CompleteQueryL()

     *       to continue the operation! Alternatively, the operation must be

     *       cancelled.

     * 

     * 

     * @see MNcdOperation

     * @see MNcdQuery

     * @param aOperation Uncounted reference to the operation object that sent

     *  the event.

     * @param aQuery Pointer to the query that must be completed. Counted, Release()

     *        must be called after use.

     * @see MNcdOperation::CompleteQueryL()

     */

    virtual void QueryReceived( MNcdLoadNodeOperation& aOperation,

                                MNcdQuery* aQuery ) = 0;

    /**

     * Called when an operation has been completed.

     *

     * 

     * @param aOperation Reference to the operation that sent the event.

     *  Uncounted; if the observer implementation wants to save

     *  the operation pointer for later use, it must call AddRef() for

     *  it first, and Release() after use.

     * @param aError Error code for operation completion. 

     *               KErrNone for successful completion, 

     *               KErrNoMasterServerUri if the master server URI has not been set 

     *               (possible only when loading root node),

     *               otherwise a system wide error code.

     */

    virtual void OperationComplete( MNcdLoadNodeOperation& aOperation,

                                    TInt aError ) = 0;

    };

#endif //  M_NCD_LOAD_NODE_OPERATION_OBSERVER_H