如何在程序中添加业务逻辑层？

Question

我创建了一个程序，该程序生成的数字多于我们在文本行中输入的数字。告诉我如何在该程序中添加业务逻辑层。

main.java

public class Main {
public static void main (String[]argc){
    GraphicalUserInterface gui = new GraphicalUserInterface();
    gui.setVisible(true);
    gui.setResizable(false);
 }
}

GraphicalUserInterface.java

import java.awt.*;
import javax.swing.*;
import java.util.concurrent.ThreadLocalRandom;
public class GraphicalUserInterface extends JFrame {

int anInt;
private JButton buttonMore = new JButton("Генерировать больше");
private JButton buttonLess = new JButton("Генерировать меньше");

private JTextField textField = new JTextField("", 5);
private JLabel labelOne = new JLabel("254");
private JLabel labelTwo = new JLabel("125");
private JLabel labelZero = new JLabel("");

public GraphicalUserInterface() {

    super("Lab1_GUI");
    this.setBounds(100, 100, 400, 150);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    Container container = this.getContentPane();
    container.setLayout(new GridLayout(3, 10, 10, 10));

    container.add(textField);
    container.add(labelZero);

    buttonMore.addActionListener(event -> {
        anInt = Integer.parseInt(textField.getText());

labelOne.setText(String.valueOf
 (ThreadLocalRandom.current().nextInt(anInt, 1000)));
    });

    container.add(buttonMore);
    container.add(labelOne);

    buttonLess.addActionListener(event -> {
        anInt = Integer.parseInt(textField.getText());
        labelTwo.setText(String.valueOf
          (ThreadLocalRandom.current().nextInt(anInt)));
    });
    container.add(buttonLess);
    container.add(labelTwo);
}
}

目前尚不清楚如何向其添加业务逻辑