☀️ WeatherApp MVC — When Clprolf Meets Spring MVC Philosophy

Everyone knows the MVC pattern.
But what if you could make it even clearer, more structurally explicit, and compatible with both desktop and web architectures?

That’s what Clprolf does —
it turns the philosophy of clarity-oriented programming into real, verifiable structure.

Let’s look at a simple example:
a WeatherApp written in Java + Clprolf annotations —
which behaves like a Spring MVC application,
but runs locally in Swing.

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🧠 1. The Idea Behind It

In Spring MVC, a Controller receives a request,
calls a Repository or Service,
and returns a View.

In Clprolf, we do exactly the same —
but we explicitly declare the roles of each component.

Component	Clprolf Role	Description
WeatherApp	@Worker_agent(Gender.STATIC)	The system launcher (like Spring Boot main)
WeatherController	@Agent	The “brain” that coordinates the logic
WeatherRepository	@Worker_agent	Technical layer fetching data
WeatherRenderer	@Worker_agent	The View layer (UI and user input)

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🏗️ 2. The Complete Code

package org.clprolf.examples.design_patterns.mvc;

import org.clprolf.framework.java.Gender;
import org.clprolf.framework.java.Worker_agent;

@Worker_agent(Gender.STATIC)
public class WeatherApp {
    public static void main(String[] args) {
        WeatherController controller = new WeatherController();
    }
}

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🧩 Controller (Agent Layer)

package org.clprolf.examples.design_patterns.mvc;

import org.clprolf.framework.java.Agent;
import org.clprolf.framework.java.Gender;

@Agent(Gender.EXPERT_COMPONENT)
public class WeatherController {
    private WeatherRepository model;
    private WeatherRenderer view;

    public WeatherController() {
        model = new WeatherRepository();
        view = new WeatherRenderer(this);
    }

    public void giveTheWeather(String location){
        model.setLocation(location);
        model.fetchWeather();
        String forecast = model.getForecast();
        view.displayForecast(forecast);
    }
}

This class acts like a Spring @Controller:
it receives a request (giveTheWeather),
calls the repository,
and updates the view.

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🎨 View (Worker Layer)

package org.clprolf.examples.design_patterns.mvc;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

import org.clprolf.framework.java.Agent;
import org.clprolf.framework.java.Contracts;
import org.clprolf.framework.java.Nature;
import org.clprolf.framework.java.Worker_agent;
import org.clprolf.framework.java.Capacity_inh;
import org.clprolf.framework.java.Advice;

@Worker_agent
public class WeatherRenderer {

    private JFrame frame;
    private JTextField locationField;
    private JTextArea forecastArea;
    private WeatherController expert;

    @Agent
    @Capacity_inh(Advice.FOR_AGENT_LIKE)
    private static interface TextFieldObserver extends @Nature ActionListener { }

    @Agent
    private class TextFieldObserverImpl implements @Contracts TextFieldObserver {
        WeatherRenderer renderer;

        public TextFieldObserverImpl(WeatherRenderer renderer){
            this.renderer = renderer;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            String location = getLocationInput();
            this.renderer.expert.giveTheWeather(location);
        }
    }

    public WeatherRenderer(WeatherController expert) {
        this.expert = expert;
        prepareViewObjects();
    }

    protected void prepareViewObjects() {
        frame = new JFrame("Weather Forecast");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 200);

        JPanel panel = new JPanel(new BorderLayout());
        JLabel locationLabel = new JLabel("Enter Location:");
        locationField = new JTextField(20);
        locationField.addActionListener(new TextFieldObserverImpl(this));

        forecastArea = new JTextArea(5, 30);
        forecastArea.setEditable(false);

        panel.add(locationLabel, BorderLayout.NORTH);
        panel.add(locationField, BorderLayout.CENTER);
        panel.add(new JScrollPane(forecastArea), BorderLayout.SOUTH);

        frame.getContentPane().add(panel);
        frame.setVisible(true);
    }

    public String getLocationInput() {
        return locationField.getText();
    }

    public void displayForecast(String forecast) {
        forecastArea.setText(forecast);
    }
}

Here, the view acts like a web frontend.
It observes user input (capacity-inherited ActionListener)
and sends the event to the controller agent.

You could almost replace Swing with HTML/JavaScript
and it would behave the same way!

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☁️ Repository (Technical Worker)

package org.clprolf.examples.design_patterns.mvc;

import org.clprolf.framework.java.Worker_agent;

@Worker_agent
class WeatherRepository {
    private String location;
    private String forecast;

    public void setLocation(String location) {
        this.location = location;
    }

    public void fetchWeather() {
        this.forecast = "Sunny with a chance of clouds";
    }

    public String getForecast() {
        return forecast;
    }
}

A pure worker: no intelligence, no UI — just technical work.
That’s exactly what a Repository or Service does in Spring MVC.

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🔄 3. The MVC Flow

User (View) → WeatherRenderer (worker_agent)
             → WeatherController (agent)
             → WeatherRepository (worker_agent)
             → back to WeatherRenderer

The same logical flow as Spring MVC —
but here, everything runs locally and instantly.

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🧠 4. Why It Matters

This example shows that Clprolf integrates seamlessly with existing patterns.
It doesn’t replace MVC, Spring, or OOP —
it simply clarifies and strengthens them.

In a Spring app, you’d just change the way communication happens
(HTTP + @GetMapping instead of direct calls) —
but your roles, responsibilities, and architecture remain identical.

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💬 5. Final Thoughts

Clprolf makes architecture visible.
You no longer guess what a class is supposed to be:
you declare it — explicitly.

A Controller is an Agent.
A Repository is a Worker_agent.
A Launcher is a Static Worker_agent.
A View is also a Worker_agent — the interface between human and machine.

In short:
Clprolf doesn’t reinvent MVC — it makes it self-explanatory.

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🧡 Summary

Traditional Role	Clprolf Equivalent	Layer
Controller	@Agent	Logic / Domain
Repository	@Worker_agent	Data / Technical
View	@Worker_agent	Presentation
Launcher	@Worker_agent(Gender.STATIC)	System entry

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🌤️ “It acts as a living interface between human and machine —
the very essence of the worker_agent.”

That’s the clarity and beauty of Clprolf.

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