/*

* Copyright (c) 2004 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:  Thin templated RGenericObserverArray.

*

*/

#ifndef __RGENERICOBSERVERARRAY_H__

#define __RGENERICOBSERVERARRAY_H__

//  INCLUDES

#include <E32Base.h>

#include "RGenericObserverArrayBase.h"

// CLASS DECLARATION

/**

 * Strictly typed observer notify mediator.

 *

 * Template typed interface to manage observer notifications

 * and notify errors. Typical mediator implementation

 * should notify given observer with type specific way.

 *

 * Notify mediator encapsulates the observer array management

 * (done by RGenericObserverArray) from observer type specific

 * notify details (implemented by concrete notify mediator).

 *

 * @since 3.0

 */

template < class T >

class MGenObserverNotifyMediator

    {

    public:

        /**

         * Observer notification.

         *

         * Template method to implement observer notification.

         * If notification handling leaves, the leave error

         * is reported back for the to same observer using the

         * MediateNotifyError() method.

         *

         * @since 3.0

         * @param aObserverToNotify The observer to notify.

         * @param aNotifyData Data to use in notification.

         */

        virtual void MediateNotifyL( T& aObserverToNotify ) = 0;

        /**

         * Observer notification from error.

         *

         * Reports the leave error propagated from

         * previous MediateNotifyL() call, back to mediator.

         *

         * @since 3.0

         * @param aObserverToNotify The notified observer which leaved.

         * @param aLeaveError The propagated leave code.

         */

        virtual void MediateNotifyError( T& aObserverToNotify, TInt aLeaveError ) = 0;

    protected:

        /**

         * Protected destructor.

         */

        virtual ~MGenObserverNotifyMediator() {}

    };

// CLASS DECLARATION

/**

 * Type templated generic observer array to manage

 * and notify observers.

 *

 * Generic observer array to manage observers and notify them

 * Adds type safety with thin template to generic

 * RGenericObserverArrayBase. Observer notification is done

 * trough generic MGenObserverNotifyMediatorBase notify

 * mediator. Array functionality supports observer remove and

 * add during the notify loop. Array doesn't own registered

 * observers.

 *

 * @since 3.0

 */

template < class T >

class RGenericObserverArray :

            private RGenericObserverArrayBase       // CSI: 70 #

    {

    public: //Constructor / destructor.

        /**

         * C++ constructor.

         */

        inline RGenericObserverArray();

        /**

         * Closes the array.

         *

         * Closes the array and frees all memory allocated to it.

         * The function must be called before this array object

         * goes out of scope.

         *

         * NOTE!

         * The function does not delete the observers whose pointers

         * are contained in the array.

         */

        void Close();

    public:  //Methods to maintain observers

        /**

         * Adds observer, handles errors by returning

         * error code.

         *

         * Adds observer, observer must point to valid

         * object. If aObserver is NULL, returns KErrArgument.

         *

         * @since 3.0

         * @see AddObserverL

         * @param aObserver The observer to add.

         * @return KErrNone is successful.

         * KErrNoMemory if out of memory.

         * KErrArgument if aObserver is NULL.

         */

        inline TInt AddObserver( const T* aObserver );

        /**

         * Adds observer, handles errors by leaving.

         *

         * Adds observer, observer must point to valid

         * object. If aObserver is NULL, leaves with

         * KErrArgument.

         *

         * @since 3.0

         * @see AddObserver

         * @param aObserver The observer to add.

         */

        inline void AddObserverL( const T* aObserver );

        /**

         * Removes observer.

         *

         * @since 3.0

         * @param aObserver The observer to remove.

         * @return KErrNone if observer was found, else KErrNotFound.

         */

        inline TInt RemoveObserver( T* aObserver );

        /**

         * Observer count.

         *

         * Gets observer count.

         *

         * @since 3.0

         * @return Current observer count.

         */

        inline TInt Count();

    public:  //Methods to notify observers

        /**

         * Observer notify implementation.

         *

         * Notifies registered observers using given

         * observer notify mediator. Prior notify

         * loop protects the internal observer array

         * state against loop time observer removing.

         *

         * @since 3.0

         * @param aNotifyMediator The notify mediator to

         * use to notify the observers. Usage of mediator

         * separates the real notify details from observer

         * array managing details.

         */

        inline void NotifyObservers( MGenObserverNotifyMediator< T >& aNotifyMediator );

        /**

         * Observer notify implementation.

         *

         * Notifies registered observers using given

         * observer notify mediator from given error.

         * Prior notify loop protects the internal

         * observer array state against loop time

         * observer removing.

         *

         * @since 3.0

         * @param aNotifyMediator The notify mediator to

         * use to notify the observers. Usage of mediator

         * separates the real notify details from observer

         * array managing details.

         * @param aError The error to mediate to error observers.

         */

        inline void NotifyErrorObservers( MGenObserverNotifyMediator< T >& aNotifyMediator,

                                          TInt aError );

        /**

         * Checks is the notify loop running.

         *

         * @return ETrue if notify loop is running. Else EFalse.

         */

        inline TBool NotifyLoopRunning() const;

    };

// Inline methods

#include "RGenericObserverArray.inl"

#endif      //__RGENERICOBSERVERARRAY_H__

//  End of File