/*

* Copyright (c) 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:  The base class for interfaces provided by widget classes.

*

*/

#ifndef I_ALFINTERFACEBASE_H

#define I_ALFINTERFACEBASE_H

namespace Alf

    {

struct IfId;

/**

 *  The base class for interfaces provided by

 *  widget classes, including CAlfWidget, CAlfModel,

 *  CAlfWidgetControl, MAlfWidgetEventHandler,

 *  MAlfElement and derived classes.

 *

 *  @lib alfwidgetmodel.lib

 *  @since S60 ?S60_version

 *  @status Draft

 */

class IAlfInterfaceBase

    {

public:

    /**

     * Default virtual destructor.

     */

    virtual ~IAlfInterfaceBase() {}

    /**

     * Interface getter with casting.

     *

     * @since S60 ?S60_version

     * @param aType The type id of the queried interface.

     * @return The queried interface, or NULL if the interface is not

     *         supported or available.

     */

    template <class T>

    static T* makeInterface(IAlfInterfaceBase* aBase)

        {

        return (aBase? static_cast<T*>(aBase->makeInterface(T::type())): 0);

        }

    /**

     * Interface getter.

     * Derived classes should always call the base class method

     * from the overridden MakeInterface.

     *

     * @since S60 ?S60_version

     * @param aType The type id of the queried interface.

     * @return The queried interface, or NULL if the interface is not

     *         supported or available.

     */

    virtual IAlfInterfaceBase* makeInterface( const IfId& aType ) = 0;

    };

    }

#endif // I_ALFINTERFACEBASE_H

// End of File