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

/** DemoLargestGUI - find the largest number in a series -- GUI version.<p>
*
* This is a follow-on program to <code>DemoLargestConsole</code>.  
* It is an example of a <i>GUI application</i>
* -- a program that interacts with the user using a <i>graphical
* user interface</i> or GUI.   With a GUI application,
* a mouse and keyboard are used to interact
* with a graphical objects presented
* in a window on the system's display.
* <p>
*
* Screen snap upon launch...<br>
* <center><img src = "DemoLargestGUI-1.gif"></center><p>
*
* Screen snap after some user input...<br>
* <center><img src = "DemoLargestGUI-2.gif"></center><p>
*
* @see <a href="DemoLargestGUI.java">source code</a>
* @author Scott MacKenzie, 2003
*/
public class DemoLargestGUI
{
   public static void main(String[] args)
   {
      // use look and feel for my system (Win32)
      try {
         UIManager.setLookAndFeel(
            UIManager.getSystemLookAndFeelClassName());
      } catch (Exception e) {}

      DemoLargestGUIFrame frame = new DemoLargestGUIFrame();
      frame.setTitle("DemoLargestGUI");
      frame.pack();
      frame.show();
   }
}

class DemoLargestGUIFrame extends JFrame implements ActionListener
{
   private JTextArea inputArea;
   private JTextArea result;

   public DemoLargestGUIFrame()
   {
      // ----------------------------------
      // construct and configure components
      // ----------------------------------

		Color tmp = this.getBackground();

      inputArea = new JTextArea(5, 30);
      inputArea.setAlignmentX(Component.LEFT_ALIGNMENT);
      inputArea.setBackground(tmp);
      inputArea.setBorder(new TitledBorder(new EtchedBorder(),
         "Enter numbers below"));

      result = new JTextArea("(result appears here)", 1, 30);
      result.setEditable(false);
      result.setAlignmentX(Component.LEFT_ALIGNMENT);
      result.setBackground(tmp);
      result.setForeground(new Color(204, 0, 0));
      result.setBorder(new TitledBorder(new EtchedBorder(),
         "Largest number is"));

      JButton findButton = new JButton("Find largest");
     
      // -------------
      // add listeners
      // -------------

      findButton.addActionListener(this);
      this.addWindowListener(new WindowCloser());

      // ------------------
      // arrange components
      // ------------------

      JPanel p1 = new JPanel();
      p1.setLayout(new BoxLayout(p1, BoxLayout.Y_AXIS));
      p1.add(inputArea);
      p1.add(Box.createRigidArea(new Dimension(0, 10)));
      p1.add(result);
      p1.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

      JPanel p2 = new JPanel();  // flow layout
      p2.add(findButton);
         
      JPanel contentPane = new JPanel(new BorderLayout());
      contentPane.add(p1, "Center");
      contentPane.add(p2, "South");
      contentPane.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

      this.setContentPane(contentPane);
   }

   // -------------------------------
   // implement ActionListener method
   // -------------------------------

   public void actionPerformed(ActionEvent ae)
   {
      double largest = findLargest(inputArea.getText());
      result.setText("" + largest);
   }

   // -------------
   // other methods
   // -------------

   public static double findLargest(String sArg)
   {
      StringTokenizer st = new StringTokenizer(sArg);

      double result = Double.MIN_VALUE;
      while (st.hasMoreTokens())
      {
         double value = Double.parseDouble(st.nextToken());
         if (value > result)
            result = value;
      }
      return result;
   }

   // -----------
   // inner class
   // -----------

   // Note: WindowAdapter implements windowClosing

   private class WindowCloser extends WindowAdapter
   {
      public void windowClosing(WindowEvent event)
      {
         System.exit(0);
      }
   }
}