/*
  * Opens a mail.
  */
 private void openMail(int id) {
   Mail m = mailbox.getMail(id);
   Terminal.println();
   if (m != null) {
     m.open();
     Terminal.println();
   }
 }
    /*
     * Shows the contents of the inbox.
     */
    private void showInbox() {
      Terminal.println("id\t\t\t from\t\t\t\t\t  " + "date\t\t\t\t\t   subject");

      List<Mail> mail = mailbox.getAllMail();
      Mail m;
      int tabCount;

      for (int i = 0; i < mail.size(); i++) {
        m = mail.get(i);

        // Print number
        if (i < 10) {
          Terminal.print(' ');
        }
        Terminal.print(i + " ");

        // Print sender
        Terminal.print(m.getSender());
        tabCount = 7 - (int) Math.round((double) m.getSender().length() / ScreenBuffer.TAB_LENGTH);
        printTabs(tabCount);

        // Print date
        Terminal.print(m.getDate());
        tabCount = 6 - (int) Math.floor((double) m.getDate().length() / ScreenBuffer.TAB_LENGTH);
        printTabs(tabCount);

        // Print subject
        Terminal.print(m.getSubject());
        Terminal.println();
      }
    }