Fluent Style Swing

FluentSwing.java

package kis;

import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class FluentSwing {
    public static void main(String[] args) {
        new Frame("hello")
                .add("North", new Panel()
                        .add(new JTextField(10))
                        .add(new Button("hello")))
                .add(new JTextArea())
                .setSize(600, 400)
                .setVisible(true);
    }
    
    interface ComponentHolder<T extends JComponent> {
        T component();
    }
    

    static class Frame {
        JFrame f;

        public Frame(String title) {
            this.f = new JFrame(title);
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        }
        Frame setSize(int w, int h) {
            f.setSize(w, h);
            return this;
        }
        Frame setVisible(boolean v) {
            f.setVisible(v);
            return this;
        }
        Frame add(String place, ComponentHolder<?> comp) {
            f.add(place, comp.component());
            return this;
        }
        Frame add(JComponent comp) {
            f.add(comp);
            return this;
        }
    }
    
    static class Button implements ComponentHolder<JButton> {
        JButton b;

        public Button(String text) {
            this.b = new JButton(text);
        }
        
        @Override
        public JButton component() {
            return b;
        }
        
        Button addActionListener(ActionListener al) {
            b.addActionListener(al);
            return this;
        }
    }
    
    static class Panel implements ComponentHolder<JPanel> {
        JPanel p;

        public Panel() {
            this.p = new JPanel();
        }
        Panel add(JComponent compo) {
            p.add(compo);
            return this;
        }
        Panel add(ComponentHolder<?> como) {
            p.add(como.component());
            return this;
        }
        @Override
        public JPanel component() {
            return p;
        }
    }
}