Swing Notification Popup

//see: http://groovy.codehaus.org/GUI+Programming+with+Groovy

import groovy.swing.*
import java.awt.*
import javax.swing.*
import javax.swing.border.*
import groovy.util.slurpersupport.NodeChild as Node
 
public class Notify { 
 def sb = new SwingBuilder()

 public static void main(String[] args) {
  // creates and displays itself
  new Notify(args)
 }

 public Notify(String[] args){
  // arg is path to xml message file, 
  // will be deleted after popup displayed
  if (args.size() != 1) return 
  
  String appTitle = ".:. Notification .:."
  String filePath = args[0]
  Color backgroundColor = Color.yellow
  Border emptyBorder = BorderFactory.createMatteBorder(5, 5, 5, 5, backgroundColor)
    
  Toolkit tk = Toolkit.getDefaultToolkit()
  Dimension screenSize = tk.getScreenSize()
  final int WIDTH = screenSize.width
  final int HEIGHT = screenSize.height
  
  int w = WIDTH / 2
  int h = HEIGHT / 2
  
  int x = (WIDTH / 2) - (w / 2)
  int y = (HEIGHT / 2) - (h / 2) - 50
  
  Font fontSubject = new Font("Serif", Font.PLAIN, 24)
  Font fontMessage = new Font("Serif", Font.PLAIN, 16)
  
  //generate frame//
  sb.dialog(id:"popupBox", title:appTitle, visible:true, alwaysOnTop:true, defaultCloseOperation:JFrame.DISPOSE_ON_CLOSE, resizable:false, location:[x, y], size:[w, h]) 
  {
   borderLayout()
   label(id:"subject", constraints:BorderLayout.NORTH, horizontalAlignment:JTextField.CENTER, font:fontSubject, "SUBJ")
   
   panel(constraints:BorderLayout.CENTER){
    gridLayout(cols:1, rows:1, hgap:1, vgap:1)
    scrollPane(border:emptyBorder) {
     textArea(id:"message", editable:false, lineWrap:true, wrapStyleWord:true, font:fontMessage, "MESG")
    }
   }
  }
  def frame = sb.popupBox
  
  //decorate frame color//
  def cp = frame.contentPane
  cp.background = backgroundColor
  sb.message.background = cp.background
  
  //populate frame data//
  File xmlFile
  Node root
  try {
   xmlFile = new File(filePath)
   root = new XmlSlurper().parse(xmlFile)
   //println root.getClass().name
  } 
  catch (Exception) {
   xmlFile = new File("")
   root = new XmlSlurper().parseText('''
    Error
    Sorry, file path or XML syntax error.
    ''')
  }
  
  sb.subject.text = root.subject.text() // if not found, subject UI label is hidden
  sb.message.text = root.message.text() ? 
   root.message.text().replaceAll('\\\\n', System.getProperty( "line.separator" )) :
   'Sorry, empty notification.'
  
  //display form//
  frame.show()
  
  try {
   xmlFile.delete()
  } catch (Exception ignore) {}
 }
}