/*

* Copyright (c) 2002-2006 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:  Provides way to notify events and register observers

*                for events

*

*/

#ifndef TSATEVENTMEDIATOR_H

#define TSATEVENTMEDIATOR_H

//  INCLUDES

#include <e32base.h>

// FORWARD DECLARATIONS

class MSatEventObserver;

class TSatEventsObserver;

// CLASS DECLARATION

/**

*  Provides way to notify events and register observers for events.

*  Observers are not owned by this class and therefore observers are

*  not deleted when TSatEventMediator instance is destroyed.

*

*  @lib SatEngine.dll

*  @since Series 60 3.0

*/

class TSatEventMediator

    {

    public:  // Constructors and destructor

        /**

        * C++ default constructor.

        */

        TSatEventMediator();

    public: // New functions

        /**

        * Notifies possible observers who are observing the event.

        * @param aEvent Integer identifying the event.

        * @return None

        */

        void Notify( TInt aEvent );

        /**

        * Registers observer for event. Same observer will not be added

        * more than once for one event.

        * @param aObserver Pointer of observer instance. Panic will occur if

        * aObserver is NULL.

        * @param aEvent Event, which will cause the notification of observer.

        * @return None

        */

        void RegisterL( MSatEventObserver* aObserver, TInt aEvent );

        /**

        * Unregisters the notification of single event.

        * @param aObserver Observer, whom event registeration will be

        * unregistered.

        * @param aEvent Event, which will be unregistered.

        * @return None

        */

        void Unregister( const MSatEventObserver* aObserver, TInt aEvent );

        /**

        * Unregisters the event observer.

        * @param aObserver Observer, whom event registeration will be

        * unregistered.

        */

        void Unregister( const MSatEventObserver* aObserver );

        /**

        * Resets the list of event observers. Used instead of destructor

        */

        void Reset();

    private:  // New functions

        /**

        * Checks if aObserver is already in the list of observers.

        * @param aObserver Observer that is checked from the list.

        * @return Pointer of the observer, where aObserver is registered.

        * Contains NULL pointer if aObserver is not already registered.

        */

        TSatEventsObserver* HasObserverInstance(

            const MSatEventObserver* aObserver ) const;

        /**

        * Deletes all observers marked as deleted during notify loop

        */

        void DeleteMarkedObservers();

    private:

        // Prohibit copy constructor if not deriving from CBase.

        TSatEventMediator( const TSatEventMediator& );

        // Prohibit assigment operator if not deriving from CBase.

        TSatEventMediator& operator=( const TSatEventMediator& );

    private:    // Data

        // event observers.

        RPointerArray<TSatEventsObserver> iEventsObservers;

        // Indicates are we notifying observers. If this flag is on,

        // observers cannot be removed from iEventsObservers. After

        // notify loop is done, observers can be replaced again

        TBool iIsNotifying;

        // Indicates are there any observers marked as deleted during

        // Notify loop

        TBool iDeletionsMarked;

    };

#endif      // TSATEVENTMEDIATOR_H

// End of File