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

public class ListTest extends JFrame implements ActionListener, ListDataListener,
                                                ListSelectionListener {
    JButton add = new JButton("Add");
    JButton remove = new JButton("Remove");
    JTextField text = new JTextField(10);
    JList theList;
    DefaultListModel model;
    
    public ListTest() {
	super("ListTest");
	addWindowListener(new WindowAdapter() {
		public void windowClosing(WindowEvent e) {
		    System.exit(0);
		}
	    });
	
	//Explicitly defining a model is the only way we can 
	//change the list contents on the fly. 
	model = new DefaultListModel();
	//Create a list using the model above.
	theList = new JList(model);
	//Add some elements to the list.
	model.addElement("one");
	model.addElement("two");
	model.addElement("three");
	model.addElement("four");
	model.addListDataListener(this);
	theList.addListSelectionListener(this);
	//Do not show more then three elements.
	theList.setVisibleRowCount(3);
	//Support scrolling by placing the list in a scroll pane.
	JScrollPane scroll = new JScrollPane(theList);
	
	//Build the UI.
	JPanel addRemove = new JPanel();    
	remove.addActionListener(this);
	addRemove.add(remove);
	add.addActionListener(this);
	addRemove.add(add);
	addRemove.add(text);
	
	Container c = getContentPane();
	c.setLayout(new BorderLayout());
	c.add(addRemove, "North");
	c.add(scroll, "Center");
	
	//Show the frame.
	pack();
	setVisible(true);
    }
    
    public void actionPerformed(ActionEvent e) {
	if (e.getSource() == add) {
	    //Add an element to the list.
	    model.addElement(text.getText());
	}
	else if (e.getSource() == remove) {
	    //Remove all elements from the list.
	    model.removeAllElements();
	}
    }
    
    public void intervalAdded(ListDataEvent e) {
	System.out.println("interval added");
	System.out.println(e.toString() + "\n");
    }
    
    public void intervalRemoved(ListDataEvent e) {
	System.out.println("interval removed");
	System.out.println(e.toString() + "\n");
    }
    
    public void contentsChanged(ListDataEvent e) {
	System.out.println("contents changed");
	System.out.println(e.toString() + "\n");
    }
    
    public void valueChanged(ListSelectionEvent e) {
	System.out.println("value changed");
	System.out.println(e.toString() + "\n");
    }
    
    public static void main(String[] args) {
	new ListTest();
    }
}