/**
  * Gets the instance of the StopButton
  *
  * @return The instance of the StopButton
  */
 public static JButton getStopButton() {
   if (stopButton == null) {
     stopButton = new JButton();
     stopButton.setText(Constants.STOP);
     stopButton.setHorizontalAlignment(SwingConstants.CENTER);
     stopButton.setFont(Constants.DEFAULT_BUTTON_FONT);
     stopButton.setAlignmentX(Component.CENTER_ALIGNMENT);
     stopButton.setActionCommand(Constants.STOP);
     stopButton.addActionListener(ButtonListener.getInstance());
     stopButton.setEnabled(false);
   }
   return stopButton;
 }
 /**
  * Gets the instance of the CenterButton
  *
  * @return The instance of the CenterButton
  */
 public static JButton getCenterButton() {
   if (centerButton == null) {
     centerButton = new JButton();
     centerButton.setText(Constants.CENTER);
     centerButton.setHorizontalAlignment(SwingConstants.CENTER);
     centerButton.setFont(new Font("Dialog", Font.BOLD, 14));
     centerButton.setAlignmentX(Component.CENTER_ALIGNMENT);
     centerButton.setActionCommand(Constants.CENTER);
     centerButton.addActionListener(ButtonListener.getInstance());
   }
   return centerButton;
 }
 /**
  * Gets the instance of the ConnectButton
  *
  * @return The instance of the ConnectButton
  */
 public static JButton getConnectButton() {
   if (connectButton == null) {
     connectButton = new JButton();
     connectButton.setText(Constants.CONNECT);
     connectButton.setHorizontalAlignment(SwingConstants.CENTER);
     connectButton.setFont(Constants.DEFAULT_BUTTON_FONT);
     connectButton.setAlignmentX(Component.CENTER_ALIGNMENT);
     connectButton.setActionCommand(Constants.CONNECT);
     connectButton.addActionListener(ButtonListener.getInstance());
   }
   return connectButton;
 }