observer_subject_adapter.hpp

#pragma once
#include <functional>
 
#include "software/multithreading/observer.hpp"
#include "software/multithreading/subject.hpp"
 
template <typename ObserverType, typename SubjectType>
class ObserverSubjectAdapter : public Observer<ObserverType>, public Subject<SubjectType>
{
   public:
    // the type of the conversion function
    using ConversionFunctionType = SubjectType(const ObserverType&);
 
    explicit ObserverSubjectAdapter(
        std::function<ConversionFunctionType> conversion_function_)
        : conversion_function(std::move(conversion_function_))
    {
    }
 
    virtual void receiveValue(ObserverType val) final;
 
   private:
    std::function<ConversionFunctionType> conversion_function;
};
 
template <typename ObserverType, typename SubjectType>
void ObserverSubjectAdapter<ObserverType, SubjectType>::receiveValue(ObserverType val)
{
    Subject<SubjectType>::sendValueToObservers(conversion_function(val));
}