MVC pattern

[leo donahue]

I've seen a few variations of the MVC pattern when it comes to swing applications. However, my question is a little bit more general than just swing and it relates to what exactly belongs in the model.

I've adapted a sample I found online regarding the MVC pattern.

Should only the controller have access to update the View?

Is the code in Model.java considered "model" code, or does what I have in Model.java actually belong in Controller.java?

MVCDemo.java

public class MVCDemo {
	
	public static void main(String[] args) {
		MVC mvc = new MVC();
	}
}

class MVC {
	private Controller controller;
	private Model model;
	private View view;
	
	MVC(){
		view = View.getInstance();
		view.addWindowListener(view);
		
		model = new Model();
		controller = new Controller(view, model);
		
		view.setVisible(true);
	}
}

Model.java

import javax.swing.JOptionPane;

public class Model {

	Model(){
		
	}
	
	void showMessage(){
		JOptionPane.showMessageDialog(null, "Hello!");
	}
	
	String setTextFields(String str){
		String returnString = str + ": " + (Math.random() * 100);
		return returnString;
	}
}

View.java

import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JButton;
import javax.swing.JTextField;


@SuppressWarnings("serial")
public class View extends JFrame implements WindowListener {

	private JPanel contentPane;
	private static View instance = null;
	private JTextField textField;
	private JTextField textField_1;
	private JTextField textField_2;
	private JButton btnNewButton;

	public View() {
		setTitle("Title");
		setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
		setBounds(100, 100, 253, 199);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		setContentPane(contentPane);
		contentPane.setLayout(null);
		
		textField = new JTextField();
		textField.setBounds(10, 11, 209, 20);
		contentPane.add(textField);
		textField.setColumns(10);
		
		textField_1 = new JTextField();
		textField_1.setBounds(10, 42, 209, 20);
		contentPane.add(textField_1);
		textField_1.setColumns(10);
		
		textField_2 = new JTextField();
		textField_2.setBounds(10, 73, 209, 20);
		contentPane.add(textField_2);
		textField_2.setColumns(10);
		
		btnNewButton = new JButton("Submit");
		btnNewButton.setBounds(130, 104, 89, 23);
		contentPane.add(btnNewButton);
	}
	
	public static View getInstance(){
		if(instance == null){
			instance = new View();
		}
		return instance;
	}
	
	void MyButtonListner(ActionListener al){
		btnNewButton.addActionListener(al);
	}

	public JTextField getTextField() {
		return textField;
	}

	public JTextField getTextField_1() {
		return textField_1;
	}

	public JTextField getTextField_2() {
		return textField_2;
	}

	@Override
	public void windowOpened(WindowEvent e) {
		
	}

	@Override
	public void windowClosing(WindowEvent e) {
		instance.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
	}

	@Override
	public void windowClosed(WindowEvent e) {

	}

	@Override
	public void windowIconified(WindowEvent e) {

	}

	@Override
	public void windowDeiconified(WindowEvent e) {

	}

	@Override
	public void windowActivated(WindowEvent e) {

	}

	@Override
	public void windowDeactivated(WindowEvent e) {

	}
}

Controller.java

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Controller {
	private View m_view;
	private Model m_model;
	
	Controller(View view, Model model){
		m_view = view;
		m_model = model;
		m_view.MyButtonListner(new AddButtonListener());
	}
	
	class AddButtonListener implements ActionListener{

		@Override
		public void actionPerformed(ActionEvent e) {
			// TODO Auto-generated method stub
			m_model.showMessage();
			m_view.getTextField().setText(m_model.setTextFields("Message 1"));
		}
		
	}
}