I am currently working on a small private project using C++ i came up with the following structure:
#include <iostream>
class A
{
std::vector<int> vec;
protected:
virtual bool onAdd(int toAdd) {
// should the 'adding' be suppressed?
// do some A specific checks
std::cout << "A::onAdd()" << std::endl;
return false;
}
public:
void add(int i) {
if(!onAdd(i)) {
// actual logic
vec.push_back(i);
}
}
};
class B : public A
{
protected:
bool onAdd(int toAdd) override {
// do some B specific checks
std::cout << "B::onAdd()" << std::endl;
return false;
}
};
In this example onAdd
is basically meant to be a callback for add
, but in a more polymorphic way.
The actual problem arises when a class C
inherits from B
and wants to override onAdd
too. In this case the implementation in B will get discarded (i.e. not called) when calling C::add
. So basically what I would like to achieve is a constructor-like behaviour where I am able to override the same method in different positions in the class hierarchy and all of those getting called.
My question now is: Is there a possibility/design to achieve this? I am sure that it wouldn't be as easy as cascading constructors, though.
Note: Don't focus too much on the add
example. The question is about the callback like structure and not if it makes sense with an add
.
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