import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JOptionPane;

/** 
 Simple harness for testing GUI code.
 
 <P>To use this class, edit the code to suit your needs.  
*/
public final class MinimalSwingApplication {
  
  /** 
   Build and display minimal GUI.
   
   <P>The GUI has a label and an OK button.
   The OK button launches a simple message dialog.
   No menu is included.
  */
  public static void main(String... aArgs){
    MinimalSwingApplication app = new MinimalSwingApplication();
    app.buildAndDisplayGui();
  }
  
  // PRIVATE

  private void buildAndDisplayGui(){
    JFrame frame = new JFrame("Test Frame"); 
    buildContent(frame);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
  }
  
  private void buildContent(JFrame aFrame){
    JPanel panel = new JPanel();
    panel.add(new JLabel("Hello"));
    JButton ok = new JButton("OK");
    ok.addActionListener(new ShowDialog(aFrame));
    panel.add(ok);
    aFrame.getContentPane().add(panel);      
  }
  
  private static final class ShowDialog implements ActionListener {
    /** Defining the dialog's owner JFrame is highly recommended. */
    ShowDialog(JFrame aFrame){
      fFrame = aFrame;
    }
    @Override public void actionPerformed(ActionEvent aEvent) {
      JOptionPane.showMessageDialog(fFrame, "This is a dialog");
    }
    private JFrame fFrame;
  }
}