What-is-the-front-controller-design-pattern #

Created: June 17, 2020 4:45 PM URL: https://www.educative.io/edpresso/what-is-the-front-controller-design-pattern The front controller design pattern is used to refine the structure of an application which: 1. The front controller receives a request from the client, authenticates it, and forwards the request to the dispatcher.

UML diagram #

What%20is%20the%20front%20controller%20design%20pattern%20d9380051288b472a831d4d2b541efd19/6238711576526848

#include
using namespace std;
// Views:
class View1{
public:
void update() {
cout << "Bills payed."
<< endl;
}
};
class View2{
public:
void update() {
cout << "Username updated."
<< endl;
}
};
class View3{
public:
void update() {
cout << "Password changed."
<< endl;
}
};
// Handlers:
class Handler1{
private:
View1* view1;
public:
Handler1() {
view1 = new View1();
}
void updateView() {
view1->update();
}
};
class Handler2{
private:
View2* view2;
public:
Handler2() {
view2 = new View2();
}
void updateView() {
view2->update();
}
};
class Handler3{
private:
View3* view3;
public:
Handler3() {
view3 = new View3();
}
void updateView() {
view3->update();
}
};
// Dispatcher:
class Dispatcher{
private:
Handler1* handler1;
Handler2* handler2;
Handler3* handler3;
public:
Dispatcher(){
handler1 = new Handler1();
handler2 = new Handler2();
handler3 = new Handler3();
}
void dispatch(string req) {
if(req == "pay bills")
handler1->updateView();
else if(req == "update username")
handler2->updateView();
else if(req == "change password")
handler3->updateView();
else
cout << "Invalid request!"
<< endl;
}
};
// Controller:
class Controller{
private:
Dispatcher* myDispatcher;
bool authUser(string user) {
if(user == "authentic")
return true;
else
return false;
}
public:
Controller(){
myDispatcher = new Dispatcher();
}
void forwardRequest(string u, string req) {
if(authUser(u))
myDispatcher->dispatch(req);
}
};
int main(){
Controller ctrl;
ctrl.forwardRequest("authentic", "pay bills");
return 0;
}