//PROGRAM 13-10
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class DemoList implements ActionListener {		
  public JFrame frame;
	
  public JList list;	
  public JButton btnTambah, btnHapus;
  public JTextField tfItem;
  public JScrollPane scroller;
		
  public DemoList() {			
    tfItem = new JTextField(12);
    tfItem.setLocation(10,20);
    tfItem.setSize(tfItem.getPreferredSize());		
		
    DefaultListModel lm;		
    lm = new DefaultListModel();
    lm.addElement("Java");
    lm.addElement("C");
    lm.addElement("C++");
		
    list = new JList(lm);		
    list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
		
    scroller = new JScrollPane(list);
    scroller.setLocation(10, 43);
    scroller.setSize(new Dimension(135, 170));
				
    btnTambah = new JButton("Tambah");
    btnTambah.setLocation(150, 20);
    btnTambah.setSize(btnTambah.getPreferredSize());  
    btnTambah.addActionListener(this);
    btnTambah.setMnemonic('T');
		
    btnHapus = new JButton("Hapus");
    btnHapus.setLocation(150, 50);
    btnHapus.setSize(btnTambah.getPreferredSize());  
    btnHapus.addActionListener(this);
    btnHapus.setMnemonic('H');						
  }
		
  public void createAndShowGUI() {
    JFrame.setDefaultLookAndFeelDecorated(true);
    frame = new JFrame("Demo JList");
    frame.setLayout(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
    frame.getContentPane().add(tfItem);
    frame.getContentPane().add(scroller);
    frame.getContentPane().add(btnTambah);
    frame.getContentPane().add(btnHapus);
		
    frame.setBounds(0, 0, 430, 350);
    frame.setLocationRelativeTo(null);

    frame.setVisible(true);
  }
	
  public void actionPerformed(ActionEvent event) {
    if (event.getSource() == btnTambah) {
      String s = tfItem.getText().trim();
      if (!s.equals("")) {
        ((DefaultListModel) list.getModel()).addElement(s);
      }
      if (list.getModel().getSize() == 1) {
        btnHapus.setEnabled(true);
      }
    }	else {
      int index = list.getSelectedIndex();
      if (index == -1) {
        JOptionPane.showMessageDialog(frame, 
	    "Anda harus memilih salah satu item " + 
          "terlebih dahulu");
        return;
      }
			
      ((DefaultListModel)list.getModel()).remove(index);
	
      int size = list.getModel().getSize();
	
      if (size == 0) {
        btnHapus.setEnabled(false);	
      } else {
        if (index == list.getModel().getSize()) {
          index--;
        }	
        list.setSelectedIndex(index);
        list.ensureIndexIsVisible(index);
      }			
    }
  }
	
  public static void main(String[] args) {		
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        DemoList app = new DemoList();
        app.createAndShowGUI();
      }
    });		
  }	
}