import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

import javax.swing.AbstractListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class Liste implements ActionListener {

    JList<Object> liste;
    JTextField eingabe;
    JLabel einLabel;
    JPanel einPanel, buttPanel;
    JButton changeButt, addButt, deleteButt;
    JListModel model = new JListModel();

    public Liste() {
        initGUI();
    }
    
    private void initGUI() {
        JFrame frame = new JFrame("Liste");
        einLabel = new JLabel("eingabe:");
        eingabe = new JTextField();
        einPanel = new JPanel(new GridLayout(1, 2));
        einPanel.add(einLabel);
        einPanel.add(eingabe);

        changeButt = new JButton("\u00E4ndern");
        changeButt.addActionListener(this);

        addButt = new JButton("hinzuf\u00FCgen");
        addButt.addActionListener(this);
        
        deleteButt = new JButton("l\u00F6schen");
        deleteButt.addActionListener(this);
        
        buttPanel = new JPanel(new GridLayout(1, 3));
        buttPanel.add(changeButt);
        buttPanel.add(addButt);
        buttPanel.add(deleteButt);

        liste = new JList<Object>(model);
        JScrollPane sp = new JScrollPane(liste);

        frame.getContentPane().add(einPanel, BorderLayout.NORTH);
        frame.getContentPane().add(sp, BorderLayout.CENTER);
        frame.getContentPane().add(buttPanel, BorderLayout.SOUTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);
        frame.setLocation(100, 100);
        frame.setVisible(true);
    }

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

    public void actionPerformed(ActionEvent e) {
        String txt = eingabe.getText();
        if (!txt.equals("") && !txt.startsWith(" ")) {
            if (e.getSource() == addButt)
                model.addElement(txt);
            if (e.getSource() == changeButt)
                model.setElement(txt, liste.getSelectedIndex());
        }
        if (e.getSource() == deleteButt)
            model.removeElement(liste.getSelectedIndex());
    }
}

class JListModel extends AbstractListModel<Object> {

    private static final long serialVersionUID = 1L;
    private ArrayList<String> data;

    public JListModel() {
        data = new ArrayList<String>();
        data.add("eins");
        data.add("zwei");
        data.add("drei");
        data.add("vier");
    }

    public int getSize() {
        return data.size();
    }

    public Object getElementAt(int index) {
        return data.get(index);
    }

    public Object getIndex(Object o) {
        return data.indexOf(o);
    }

    public void setElement(String s, int index) {
        data.set(index, s);
        update(0, this.getSize());
    }

    public void addElement(String s) {
        data.add(s);
        update(this.getSize() - 1, this.getSize());
    }
    
    public void removeElement(int index){
        data.remove(index);
        update(0, this.getSize());
    }

    public void update(int von, int bis) {
        fireIntervalAdded(this, von, bis);
    }
}