mrptEvent.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#ifndef mrptEvent_H
#define mrptEvent_H

#include <mrpt/system/datetime.h>

namespace mrpt
{
namespace utils
{
class CObservable;

/**  The basic event type for the observer-observable pattern in MRPT.
  *   You can sub-class this base class to create custom event types, then
  *    tell between them in runtime with isOfType<T>(), for example:
  * \code
  *   if (e.isOfType<mrptEventOnDestroy>())
  *   {
  *     const mrptEventOnDestroy* ev = e.getAs<mrptEventOnDestroy>();
  *     ev-> ...
  *   }
  * \endcode
  *
  * \sa CObserver, CObservable
 * \ingroup mrpt_base_grp
  */
class mrptEvent
{
   protected:
        /** Just to allow this class to be polymorphic */
        virtual void do_nothing() {}
   public:
        /** Default ctor */
        inline mrptEvent() : timestamp(mrpt::system::now()) {}
        template <class EVENTTYPE>
        inline bool isOfType() const
        {
                return dynamic_cast<const EVENTTYPE*>(this) != nullptr;
        }

        template <class EVENTTYPE>
        inline const EVENTTYPE* getAs() const
        {
                return dynamic_cast<const EVENTTYPE*>(this);
        }

        template <class EVENTTYPE>
        inline EVENTTYPE* getAsNonConst() const
        {
                return const_cast<EVENTTYPE*>(dynamic_cast<const EVENTTYPE*>(this));
        }

        mrpt::system::TTimeStamp timestamp;

};  // End of class def.

/**  An event sent by any CObservable object (automatically) just before being
 * destroyed and telling its observers to unsubscribe.
 * \ingroup mrpt_base_grp
  */
class mrptEventOnDestroy : public mrptEvent
{
   protected:
        /** Just to allow this class to be polymorphic */
        void do_nothing() override {}
   public:
        inline mrptEventOnDestroy(const CObservable* obj) : source_object(obj) {}
        const CObservable* source_object;

};  // End of class def.

}  // End of namespace
}  // end of namespace
#endif