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

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class LookAndFeel implements ActionListener {

    private final JFrame frame;
    private JLabel label;
    private JButton lfButton;
    private JTextArea area;
    private JScrollPane pane;
    private JMenuItem exit;
    private int lAF = 1;

    public LookAndFeel() {
        frame = new JFrame();
        initComponents(frame);

        updateLAF(frame);
    }

    private void initComponents(JFrame frame) {
        if(frame == null) {
            System.err.println("Frame not initialized");
            System.exit(1);
        }
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("Datei");
        exit = new JMenuItem("exit");
        exit.addActionListener(this);
        menu.add(exit);
        menuBar.add(menu);
        lfButton = new JButton("L & F \u00e4ndern");
        lfButton.addActionListener(this);
        label = new JLabel();
        area = new JTextArea();
        pane = new JScrollPane(area, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

        JPanel buttPanel = new JPanel(new FlowLayout());
        buttPanel.add(lfButton);

        JPanel mainPanel = new JPanel(new BorderLayout());
        mainPanel.setBorder(BorderFactory.createEmptyBorder(30, 30, 10, 30));

        mainPanel.add(label, BorderLayout.NORTH);
        mainPanel.add(pane, BorderLayout.CENTER);
        mainPanel.add(buttPanel, BorderLayout.SOUTH);

        frame.add(menuBar, BorderLayout.NORTH);
        frame.add(mainPanel, BorderLayout.CENTER);
        frame.setLocationRelativeTo(null);

        frame.setTitle("Look and Feel-Demo");
        frame.setSize(240, 180);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    private void updateLAF(JFrame frame) {
        try {
            String plaf = "";
            if (lAF == 1) {
                plaf = "javax.swing.plaf.metal.MetalLookAndFeel";
            } else if (lAF == 2) {
                plaf = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
            } else if (lAF == 3) {
                plaf = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
            } else if (lAF == 4) {
                plaf = "com.sun.java.swing.plaf.gtk.GTKLookAndFeel";
            } else if (lAF == 5) {
                plaf = UIManager.getSystemLookAndFeelClassName();
            }
            setText(plaf);
            label.setText(" L & F Nr.: " + new Integer(lAF).toString());

            UIManager.setLookAndFeel(plaf);
            SwingUtilities.updateComponentTreeUI(frame);

        } catch (UnsupportedLookAndFeelException ue) {
            System.err.println(ue.toString());
        } catch (ClassNotFoundException ce) {
            System.err.println(ce.toString());
        } catch (InstantiationException ie) {
            System.err.println(ie.toString());
        } catch (IllegalAccessException iae) {
            System.err.println(iae.toString());
        }
    }

    private void setText(String text) {
        area.setText(text);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == lfButton) {
            lAF++;
            if (lAF > 5)
                lAF = 1;
            updateLAF(frame);
        }
        if (e.getSource() == exit) {
            System.exit(0);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new LookAndFeel());
    }
}