Gui.java

package view;

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

public class Gui extends JFrame implements ActionListener {
	private static final long serialVersionUID = 211431534849779406L;
	private static String ADMIN_USERNAME = "Admin";
	private static String ADMIN_PASSWORD = "Admin";
	private static String CUSTOMER_USERNAME = "Customer1";
	private static String CUSTOMER_PASSWORD = "Customer1";
	private JTextArea username;
	private JPasswordField password;
	private JPanel mainView, userSection, passSection, loginSection;
	private JTextField user, pass;
	private JButton login;

	public Gui() {
		this.setTitle("Program");
		this.setSize(300, 300);
		this.setLocationRelativeTo(null);
		initializeView();

		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setVisible(true);
	}

	private void initializeView() {
		mainView = new JPanel();
		mainView.setLayout(new BoxLayout(mainView, BoxLayout.Y_AXIS));
		user = new JTextField("Username:");
		user.setEditable(false);
		pass = new JTextField("Password:");
		pass.setEditable(false);
		username = new JTextArea(1, 10);
		password = new JPasswordField(10);
		userSection = new JPanel();
		userSection.setLayout(new FlowLayout());
		passSection = new JPanel();
		passSection.setLayout(new FlowLayout());
		loginSection = new JPanel();
		login = new JButton("Log in");
		login.addActionListener(this);
		userSection.add(user);
		userSection.add(username);
		passSection.add(pass);
		passSection.add(password);
		loginSection.add(login);
		mainView.add(userSection);
		mainView.add(passSection);
		mainView.add(loginSection);
		this.add(mainView);
	}

	@Override
	public void actionPerformed(ActionEvent event) {
		if (event.getSource() == login) {
			String loginUsername = username.getText();
			String loginPassword = String.copyValueOf(password.getPassword());
			if (loginUsername.equals(ADMIN_USERNAME) && loginPassword.equals(ADMIN_PASSWORD)) {
				this.dispose();
				new UserView();
			} else if (loginUsername.equals(CUSTOMER_USERNAME) && loginPassword.equals(CUSTOMER_PASSWORD)) {
				this.dispose();
				new CustomerView();
			} else {
				JOptionPane.showMessageDialog(this,
						"Not correct username or password.Please write again more carefully.", "Error",
						JOptionPane.ERROR_MESSAGE);
			}
		}
	}
}