Example: maps_observer_pattern_example

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2024, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/maps/CSimplePointsMap.h>
#include <mrpt/obs/CObservation2DRangeScan.h>
#include <mrpt/obs/stock_observations.h>
#include <mrpt/system/CObserver.h>

#include <iostream>

using namespace mrpt::obs;
using namespace mrpt::maps;
using namespace mrpt::poses;
using namespace mrpt::system;
using namespace std;

// Load a example laser scan:
CObservation2DRangeScan getScan()
{
  CObservation2DRangeScan scan1;
  stock_observations::example2DRangeScan(scan1);
  return scan1;
}

class MyObserver : public mrpt::system::CObserver
{
 protected:
  void OnEvent(const mrptEvent& e) override
  {
    if (e.isOfType<mrptEventMetricMapClear>())
      cout << "[MyObserver] Event received: mrptEventMetricMapClear\n";
    else if (e.isOfType<mrptEventMetricMapInsert>())
      cout << "[MyObserver] Event received: mrptEventMetricMapInsert\n";
    else if (e.isOfType<mrptEventOnDestroy>())
      cout << "[MyObserver] Event received: mrptEventOnDestroy\n";
    else
      cout << "[MyObserver] Event received: Generic mrptEvent \n";
  }
};

// ------------------------------------------------------
//              TestObserverPattern
// ------------------------------------------------------
void TestObserverPattern()
{
  CSimplePointsMap::Ptr map1 = CSimplePointsMap::Create();

  CObservation2DRangeScan obs = getScan();

  // Start observer:
  MyObserver observer;
  observer.observeBegin(*map1);

  // Insert:
  for (int i = 0; i < 3; i++) map1->insertObservation(obs);

  // Clear:
  map1->clear();

  // Insert again:
  map1->insertObservation(obs);

  // Destroy
  map1.reset();
}

int main()
{
  try
  {
    TestObserverPattern();

    return 0;
  }
  catch (exception& e)
  {
    cout << "MRPT exception caught: " << e.what() << endl;
    return -1;
  }
  catch (...)
  {
    printf("Another exception!!");
    return -1;
  }
}