30) front controller design pattern

类别：

 

问题：

 

方案：

 

 

 

示例：

 

public class FrontControllerPatternDemo {
    public static void main(String[] args) {
        FrontController frontController = new FrontController();
        frontController.dispatchRequest("home");
        frontController.dispatchRequest("student");
    }

}

class HomeView {
    public void show() {
        System.out.println("Displaying Home Page");
    }
}

class StudentView {
    public void show() {
        System.out.println("Displaying Student Page");
    }
}

class Dispatcher {
    private StudentView studentView;
    private HomeView homeView;

    public Dispatcher() {
        studentView = new StudentView();
        homeView = new HomeView();
    }

    public void dispatch(String request) {
        if (request.equalsIgnoreCase("student")) {
            studentView.show();
        } else {
            homeView.show();
        }
    }
}

class FrontController {
    private Dispatcher dispatcher;

    public FrontController() {
        dispatcher = new Dispatcher();
    }

    private boolean isAuthenticUser() {
        System.out.println("User is authenticated successfully.");
        return true;
    }

    private void trackRequest(String request) {
        System.out.println("Page requested: " + request);
    }

    public void dispatchRequest(String request) {
        // log each request
        trackRequest(request);
        // authenticate the user
        if (isAuthenticUser()) {
            dispatcher.dispatch(request);
        }
    }
}

 

Page requested: home
User is authenticated successfully.
Displaying Home Page
Page requested: student
User is authenticated successfully.
Displaying Student Page

 

应用：

 

不足：(

 

优化：）