.. _program_listing_file_MRML_vtkMRMLLayerDMObjectEventObserver.h:

Program Listing for File vtkMRMLLayerDMObjectEventObserver.h
============================================================

|exhale_lsh| :ref:`Return to documentation for file <file_MRML_vtkMRMLLayerDMObjectEventObserver.h>` (``MRML/vtkMRMLLayerDMObjectEventObserver.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   // LayerDM includes
   #include "vtkSlicerLayerDMModuleMRMLExport.h"
   
   // VTK includes
   #include <vtkCommand.h>
   #include <vtkObject.h>
   #include <vtkSmartPointer.h>
   #include <vtkWeakPointer.h>
   
   // STL includes
   #include <functional>
   #include <map>
   #include <set>
   #include <variant>
   #include <vector>
   
   class vtkCallbackCommand;
   
   class VTK_SLICER_LAYERDM_MODULE_MRML_EXPORT vtkMRMLLayerDMObjectEventObserver : public vtkObject
   {
   public:
     struct UpdateGuard;
     static vtkMRMLLayerDMObjectEventObserver* New();
     vtkTypeMacro(vtkMRMLLayerDMObjectEventObserver, vtkObject);
   
     bool UpdateObserver(vtkObject* prevObj, vtkObject* obj, unsigned long event = vtkCommand::ModifiedEvent);
     bool UpdateObserver(vtkObject* prevObj, vtkObject* obj, const std::vector<unsigned long>& events);
   
     void RemoveObserver(vtkObject* obj);
   
     void SetUpdateCallback(const std::function<void(vtkObject* node)>& callback);
     void SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId)>& callback);
     void SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId, void* callData)>& callback);
   
     bool SetBlocked(bool isBlocked);
   
     struct UpdateGuard
     {
       UpdateGuard(vtkMRMLLayerDMObjectEventObserver* obs);
       ~UpdateGuard();
   
     private:
       vtkMRMLLayerDMObjectEventObserver* m_obs;
       bool m_wasBlocked{};
     };
   
   protected:
     vtkMRMLLayerDMObjectEventObserver();
     ~vtkMRMLLayerDMObjectEventObserver() override;
   
   private:
     void AddObserver(vtkObject* obj, unsigned long event);
   
     vtkSmartPointer<vtkCallbackCommand> m_updateCommand{};
     std::map<vtkWeakPointer<vtkObject>, std::set<unsigned long>> m_obsMap{};
   
     std::variant<std::function<void(vtkObject* node)>,
                  std::function<void(vtkObject* node, unsigned long eventId)>,
                  std::function<void(vtkObject* node, unsigned long eventId, void* callData)>>
       m_callback;
     bool m_isBlocked;
   };