/*

* Copyright (c) 2006-2009 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:  Image Composer's listener for changes in db location relations

 *

*/

#ifndef LOCATIONRELATIONOBSERVER_H

#define LOCATIONRELATIONOBSERVER_H

#include "mdeharvestersession.h"

#include "mdequery.h"

// forward declarations

class CMdENamespaceDef;

class CComposerImagePlugin;

/**

 *  CLocationRelationObserver

 * 

 */

class CLocationRelationObserver : public CBase, public MMdERelationObserver, public MMdEQueryObserver

	{

public:

	// Constructors and destructor

	/**

	 * Destructor.

	 */

	~CLocationRelationObserver();

	/**

	 * Two-phased constructor.

	 */

	static CLocationRelationObserver* NewL( CMdESession* aSession, CComposerImagePlugin* aComposer );

protected:

	/**

	 * Called to notify the observer that new relations has been

	 * added/modified/removed in the metadata engine database.

	 *

	 * @param aSession session

	 * @param aType defines if relation was added/modified/remove

	 * @param aRelationIdArray IDs of relations

	 */

	void HandleRelationNotification(CMdESession& aSession,

			TObserverNotificationType aType,

			const RArray<TItemId>& aRelationIdArray);

    /**

     * Called to notify the observer that new results have been received 

     * in the query.

     * From MMdEQueryObserver.

     *

     * @param aQuery              Query instance that received new results.

     * @param aFirstNewItemIndex  Index of the first new item that was added

     *                            to the result item array.

     * @param aNewItemCount       Number of items added to the result item 

     *                            array.

     *

     * No implementation needed!

     */

    void HandleQueryNewResults( CMdEQuery& /*aQuery*/,

        TInt /*aFirstNewItemIndex*/, TInt /*aNewItemCount*/ );

    /**

     * Handle query results.

     * From MMdEQueryObserver.

     *

     * @param aQuery   Query instance that received new results.

     * @param aError   Error code.

     */

    void HandleQueryCompleted( CMdEQuery& aQuery, TInt aError );

private:

	/**

	 * Constructor for performing 1st stage construction

	 */

	CLocationRelationObserver();

	/**

	 * EPOC default constructor for performing 2nd stage construction

	 */

	void ConstructL( CMdESession* aSession, CComposerImagePlugin* aComposer );

    /**

     * Query the related image object ids from MdE database.

     * @param aObjectIdArray  Array of Location object database ids.

     */

    void QueryRelationItemsL( );

private:

	/**

	 * Pointer to default Mde namespace.

	 */

	CMdENamespaceDef* iDefaultNamespace;

	/**

	 * Pointer to Mde session.

	 */

	CMdESession* iSession;

	/**

	 * Pointer to a composer.

	 */

	CComposerImagePlugin* iComposer;	

    /**

     * MdE query object to use for querying relations

     */

    CMdERelationQuery* iQuery;	

    TBool iQueryStarted;

    RArray<TItemId> iRelationIdArray;

	};

#endif // LOCATIONRELATIONOBSERVER_H