/*

* 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:  Base class for hierarchical list orderings.

*

*/

#ifndef C_AKNTREEORDERING_H

#define C_AKNTREEORDERING_H

#include <e32base.h>

class CAknTreeItem;

/**

 *  Tree ordering.

 *

 *  An instance of @c CAknTreeOrdering class specifies the order of children

 *  of a tree node. The tree can be sorted by applying the ordering to every

 *  node in the tree.

 *

 *  @lib aknhlist.lib

 *  @since S60 v3.2

 */

NONSHARABLE_CLASS( CAknTreeOrdering ) : public CBase

    {

public:

    /**

     * Destructor.

     */

    ~CAknTreeOrdering();

    /**

     * Compares to tree items.

     *

     * @param aFirst First item.

     *

     * @param aSecond Second item.

     *

     * @return Positive, if the first item is greater than the second item;

     *      negative, if the first item is less than the second item;

     *      and zero, if the items are equal.

     */

    virtual TInt Compare( const CAknTreeItem& aFirst,

        const CAknTreeItem& aSecond ) = 0;

protected:

    /**

     * Default C++ constructor.

     */

    CAknTreeOrdering();

    };

#endif // C_AKNTREEORDERING_H