Layout.java

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

public class Layout extends JFrame {

	private JButton lb, cb, rb;
	private FlowLayout layout;
	private Container container;

	public Layout() {
		super("The title");
		layout = new FlowLayout();
		container = getContentPane();
		setLayout(layout);

		lb = setAllLayouts(lb, "Left");
		cb = setAllLayouts(cb, "Center");
		rb = setAllLayouts(rb, "Right");
	}

	public JButton setAllLayouts(JButton bb, String s) {
		bb = new JButton(s);
		this.add(bb);
		bb.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent event) {
				if (event.getSource() == lb)
					layout.setAlignment(FlowLayout.LEFT);

				else if (event.getSource() == cb)
					layout.setAlignment(FlowLayout.CENTER);

				else if (event.getSource() == rb)
					layout.setAlignment(FlowLayout.RIGHT);

				layout.layoutContainer(container);
			}
		});
		return bb;
	}
}