/*

* Copyright (c) 2007-2008 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:    

*

*/

#ifndef C_HNQUERYCOLLECTOR_H

#define C_HNQUERYCOLLECTOR_H

#include <e32base.h>

class CLiwGenericParamList;

class CHnMdQueries;

class CHnServiceHandler;

class CHnMdQuery;

// CLASS DECLARATION

/**

 * Query Results Collector - Callback Interface 

 * 

 * @lib hnmetadatamodel

 * @since S60 5.0

 * @ingroup group_hnmetadatamodel

 */

class MHnQueryResultCollectorNotification

	{

public:

	/**

	 * Callback function called after results are collected

	 * 

	 * 	 

	 * @since S60 5.0

     * @param aResults Results collected for the query.

	 */

	virtual void ResultsCollectedL( CLiwGenericParamList* aResults ) = 0; 

	};

// CLASS DECLARATION

/**

 * Query Results Collector.

 * 

 * This class is responsible for collecting queries results.

 * 

 * @lib hnmetadatamodel

 * @since S60 5.0

 * @ingroup group_hnmetadatamodel

 */

NONSHARABLE_CLASS( CHnQueryResultCollector ): public CActive

	{

public:

    /**

     * Two-phase constructor.

     *

     * @since S60 5.0

     * @param aQueries Queries to operate on.

     * @param aParams Parameters.

     * @return Fully constructed object.

     */

	static CHnQueryResultCollector* NewL( const CHnMdQueries& aQueries ,

	                               const CLiwGenericParamList& aParams);

	/**

     * Two-phase constructor.

     *

     * @since S60 5.0

     * @param aQueries Queries to operate on.

     * @param aParams Parameters.

     * @return Fully constructed object.

     */

	static CHnQueryResultCollector* NewLC( const CHnMdQueries& aQueries,

                                  const CLiwGenericParamList& aParams );

    /**

     * Destructor.

     */

	~CHnQueryResultCollector();

    /**

     * Starts performing queries asynchronously.

     *

     * @since S60 5.0

     * @param aNotification callback interface - ResultCollectedL method calles

     *                      when queries results collected.

     */

	void StartAsynchL( MHnQueryResultCollectorNotification* aNotification );

protected:

    // from CActive

    /**

     * Resets the current query results.

     */

    void DoCancel();

    /**

     * Handles query result collection.

     */

    void RunL();    

private:

    /**

     * Standard C++ constructor.

     * 

     * @param aQueries Queries for which results are to be executed.

     * @param aParams Parameters for the queries.

     */

	CHnQueryResultCollector( const CHnMdQueries& aQueries,

	                         const CLiwGenericParamList& aParams );

    /**

     * Standard symbian 2nd phase constructor.

     *

     */

	void ConstructL();

    /**

     * Starts performing next query from a raw.

     * 

     */	

	void ExecQueryAsynchL();

	/**

     * Resets iterator and current results.

     */

	void ResetL();

	/**

     * Check if there is another query waiting.

     * 

     * @return ETrue if there is another query waiting.

     */

	TBool NextQuery();

    /**

     * Removes items.

     * 

     */

	void HandleQueryResultsL();

    /**

     * Executes query on Service Handler.

     * 

     * @param aQuery Query to be executed.

     */

    void ExecQueryL( CHnMdQuery& aQuery );

private:

	/**

     * Queries.

     * Not Own.

     */

	const CHnMdQueries& iQueries;

	/**

     * Own.

     */

	CLiwGenericParamList* iResults;

	/**

     * Not Own.

     */

	const CLiwGenericParamList& iParams;

	/**

     * Own.

     */

	TInt iQueryIterator;

	/**

     * Own.

     */

	CLiwGenericParamList* iCurrentQueryResults;

	/**

     * Not Own.

     */

	MHnQueryResultCollectorNotification* iNotification;

	/**

     * Service handler.

     * Own.

     */

    CHnServiceHandler* iSh;

	};

#endif // C_HNQUERYCOLLECTOR_H