What is the main role of a controller in software system architecture?

The controller in software architecture (for example, in MVC) acts as an intermediary between the model and the view.

The main roles of the controller:

• Receive and process user input.
• Update the model based on user actions.
• Update the view in response to changes in the model.

Thus, the controller manages the interaction logic between data and interface, ensuring separation of responsibilities.

An example in Java (simplified):

public class UserController {
    private UserModel model;
    private UserView view;

    public UserController(UserModel model, UserView view) {
        this.model = model;
        this.view = view;
    }

    public void updateUserName(String name) {
        model.setName(name);
        view.refresh(model);
    }
}

Here, the controller receives data from the user, updates the model, and then updates the view.