S60 3rd Edition SDK for Symbian OS Example Applications Guide

LandmarksDbEventHandler.h

/*
* ==============================================================================
*  Name        : LandmarksDbEventHandler.h
*  Part of     : Landmark Reference Application
*  Interface   : -
*  Description : See class description below
*  Version     : 1.0
*
*  Copyright (c) 2004-2006 Nokia Corporation.
*  This material, including documentation and any related 
*  computer programs, is protected by copyright controlled by 
*  Nokia Corporation.
* ==============================================================================
*/

#ifndef __LANDMARKS_DB_EVENT_HANDLER_H__
#define __LANDMARKS_DB_EVENT_HANDLER_H__

// INCLUDES
#include "LandmarksDbObserver.h"
#include <e32base.h>
#include <epos_landmarks.h>

// FORWARD DECLARATIONS
class CPosLandmarkDatabase;
class MLandmarksDbEventObserver;

// CLASS DECLARATION

/**
*  In the Landmark reference application there is only one instance of 
*  CLandmarksDbEventHandler. It is the only object observing the 
*  default landmark database directly. Other objects that want to observe the 
*  database must register to this object. When an event occurs this object 
*  broadcasts it to all registered observers.
*/
class CLandmarksDbEventHandler : public CActive
    {
    public: // Constructors and destructor

        /**
        * C++ constructor.
        *
        * @param aDb the database to observer
        */
        CLandmarksDbEventHandler(
            CPosLandmarkDatabase& aDb);

        /**
        * Destructor.
        */
        ~CLandmarksDbEventHandler();

    public: // New functions

        /**
        * AddObserverL registers a db observer.
        *
        * @param aObserver the observer to register
        */
        void AddObserverL(MLandmarksDbObserver* aObserver);

    protected: // from CActive

        /**
        * Handles an active object’s request completion event.
        */
        void RunL();

        /**
        * Implements cancellation of an outstanding request.
        */
        void DoCancel();

        /**
        * Handles a leave occurring in the request completion event 
        * handler RunL().
        *
        * @return KErrNone
        */
        TInt RunError(TInt aError);

    private:

        /**
        * Starts observing of db enevs
        */
        void ObserveEvents();

    private:

        //! The database to observe
        CPosLandmarkDatabase& iDb;

        //! A db event to be reported
        TPosLmEvent iEvent;

        //! An array of registered observers
        RPointerArray<MLandmarksDbObserver> iDbObservers;

    };


#endif // __LANDMARKS_DB_EVENT_HANDLER_H__

// End of File

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© Nokia 2006