@Override public void keyPressed ( KeyEvent arg0 ) {
    if ( arg0.getKeyCode ( ) == KeyEvent.VK_DOWN ) {
      GUI.commandHistoryLocation-- ;
      if ( GUI.commandHistoryLocation >= 0
          && GUI.commandHistoryLocation < GUI.commandHistory.size ( ) ) {
        this.console.setText ( GUI.commandHistory
            .get ( GUI.commandHistoryLocation ) ) ;
      } else {
        GUI.commandHistoryLocation = 0 ;
      }
    } else if ( arg0.getKeyCode ( ) == KeyEvent.VK_UP ) {
      GUI.commandHistoryLocation++ ;
      if ( GUI.commandHistoryLocation >= 0
          && GUI.commandHistoryLocation < GUI.commandHistory.size ( ) ) {
        this.console.setText ( GUI.commandHistory
            .get ( GUI.commandHistoryLocation ) ) ;
      } else {
        GUI.commandHistoryLocation = GUI.commandHistory.size ( ) - 1 ;
      }
    }
  }