// Example of setting up pull-down Menus and JFileChooser using Swing Classes

import java.io.*;  // need this to do files
import java.awt.event.*;  // event processing requirements
import javax.swing.*; // we will use Swing...

class StudentDB extends JFrame implements ActionListener
{
  JMenuBar mb;
  JMenuItem openItem, closeItem, exitItem;
  JMenuItem addFresh, addSoph, addJunior, addSenior,
    showAll, showSingle, deleteStudent;

  StudentDB()
  {
    mb = new JMenuBar();
    JMenu m1 = new JMenu("File");
    openItem = new JMenuItem("Open File");
    closeItem = new JMenuItem("Close File");
    exitItem = new JMenuItem("Exit");
    m1.add(openItem);
    m1.add(closeItem);
    m1.add(exitItem);


    JMenu m2 = new JMenu("Commands");
    JMenu m3 = new JMenu("Add");
    addFresh = new JMenuItem("Add Freshman");
    addSoph = new JMenuItem("Add Sophomore");
    addJunior = new JMenuItem("Add Junior");
    addSenior = new JMenuItem("Add Senior");
    deleteStudent = new JMenuItem("Delete Student");
    showSingle = new JMenuItem("Show Student");
    showAll = new JMenuItem("Show All");
    m3.add(addFresh);
    m3.add(addSoph);
    m3.add(addJunior);
    m3.add(addSenior);
    m2.add(m3);
    m2.add(deleteStudent);
    m2.add(showSingle);
    m2.add(showAll);
    mb.add(m1);
    mb.add(m2);

    setJMenuBar(mb);
    openItem.addActionListener(this);
    closeItem.addActionListener(this);
    exitItem.addActionListener(this);
    addFresh.addActionListener(this);
    addSoph.addActionListener(this);
    addJunior.addActionListener(this);
    addSenior.addActionListener(this);
    deleteStudent.addActionListener(this);
    showSingle.addActionListener(this);
    showAll.addActionListener(this);
    
  }

  public void actionPerformed (ActionEvent e)
  {
    if (e.getSource() == addFresh)
      {
	// Freshman selected...
	JOptionPane.showMessageDialog(null, "Freshman selected!!", "Add Student", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == addSoph)
      {
	JOptionPane.showMessageDialog(null, "Sophomore selected!!", "Add Student", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == addSenior)
      {
	JOptionPane.showMessageDialog(null, "Senior selected!!", "Add Student", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == addJunior)
      {
	JOptionPane.showMessageDialog(null, "Junior selected!!", "Add Student", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == deleteStudent)
      {
	JOptionPane.showMessageDialog(null, "Delete Student selected!!", "Delete Student", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == showSingle)
      {
	JOptionPane.showMessageDialog(null, "Display (individual) selected!!", 
		    "Display Student", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == showAll)
      {
	JOptionPane.showMessageDialog(null, "Display ALL Selected!!", "Show all", JOptionPane.PLAIN_MESSAGE);
      }
    else if (e.getSource() == exitItem)
      {
	setVisible(false);
      }
    else if (e.getSource() == openItem)
      {
	JFileChooser fc = new JFileChooser();
	fc.setFileSelectionMode(JFileChooser.FILES_ONLY);
	int result = fc.showOpenDialog(this);
	if (result == JFileChooser.CANCEL_OPTION)
	  JOptionPane.showMessageDialog(null, 
					"You cancelled file selection", 
					"Open File: ERROR",
					JOptionPane.ERROR_MESSAGE);
	else
	  {
	    File f = fc.getSelectedFile();
	    if ( f == null ||
		 f.getName().equals(""))
	      JOptionPane.showMessageDialog(null, 
					"Invalid File Name!!", 
					"Open File: ERROR",
					JOptionPane.ERROR_MESSAGE);
	    else
	      JOptionPane.showMessageDialog(null, 
				    "File: " + f.getName(), 
				    "Open File Result",
				    JOptionPane.PLAIN_MESSAGE);
	  }
      }
    else if (e.getSource() == closeItem)
      JOptionPane.showMessageDialog(null, 
				    "Close is not implemented", 
				    "Attention",
				    JOptionPane.PLAIN_MESSAGE);
  }
  public static void main (String args[])
  {
    StudentDB application = new StudentDB();
    application.setSize(200,200);
    application.setVisible(true);
  }

}